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1.  Serum antibodies to pneumolysin in patients with pneumonia. 
Journal of Clinical Microbiology  1988;26(1):96-100.
Serum antibodies to purified pneumolysin were determined by enzyme-linked immunosorbent assay (ELISA) in paired samples from 406 adult patients with community-acquired pneumonia and in samples from 184 healthy controls. A high sensitivity (83%) was obtained in patients with blood culture-confirmed pneumococcal pneumonia. In patients with a tentative pneumococcal diagnosis based on culture of samples from the sputum or the nasopharynx, 45% were positive by ELISA. The difference likely reflected the different relevance of cultural findings for the diagnosis of pneumococcal pneumonia. A significant rise in ELISA titer was found in 17% of the patients. When the diagnosis was also based on high titers, 25% were positive. Pneumococcal pneumonia diagnosed by the pneumolysin ELISA was significantly more common in the patients with a more severe disease and who required hospitalization (21 versus 5% for outpatients). Younger patients were more often positive for pneumococci as determined by high titers, while older patients showed titer rises. Mixed infections with other infectious agents were not uncommon. The finding of low titers in acute-phase samples from positive patients and in the youngest and oldest age groups of healthy controls were unexpected, indicating that further studies on the role of pneumolysin in pneumococcal disease are warranted.
PMCID: PMC266201  PMID: 3343319
2.  Pneumolysin PCR-Based Diagnosis of Invasive Pneumococcal Infection in Children 
Journal of Clinical Microbiology  1999;37(3):633-637.
Blood-based pneumolysin PCR was compared to blood culture and detection of pneumolysin immune complexes, as well as to detection of antibodies to pneumolysin and to C polysaccharide, in the diagnosis of pneumococcal infection in 75 febrile children. Invasive pneumococcal infection was suspected on clinical grounds in 67 of the febrile children, and viral infection was suspected on clinical grounds in 8 of the febrile children. In addition, 15 healthy persons were examined to test the specificity of the PCR assay. Plasma, serum, and leukocyte fractions were analyzed by PCR. The combination of all test results led to the diagnosis of pneumococcal infection in 25 patients. Pneumolysin PCR was positive in 44% of these children, an increase occurred in the pneumolysin antibodies in 39% and in the C polysaccharide antibodies in 30% of the patients; pneumolysin immune complexes were found in convalescent serum in 30%, pneumolysin immune complexes occurred in acute-phase serum samples in 16%, and a positive blood culture was found in 20% of the patients. None of the healthy controls had positive results by PCR. The results suggest that the diagnosis of Streptococcus pneumoniae infection from blood samples necessitates the use of several different assays. Pneumolysin PCR was the most sensitive assay, but its clinical value is reduced by the fact that three blood fractions are needed.
PMCID: PMC84500  PMID: 9986825
3.  Diagnosis of Streptococcus pneumoniae Infections in Adults with Bacteremia and Community-Acquired Pneumonia: Clinical Comparison of Pneumococcal PCR and Urinary Antigen Detection▿  
Journal of Clinical Microbiology  2009;47(4):1046-1049.
The diagnosis of severe Streptococcus pneumoniae infection relies heavily on insensitive culture techniques. To improve the usefulness of PCR assays, we developed a dual-PCR protocol (targeted at pneumolysin and autolysin) for EDTA blood samples. This was compared to the Binax NOW S. pneumoniae urine antigen test in patients with bacteremic pneumococcal infections. Patients with nonbacteremic community-acquired pneumonia also were tested by these methods to determine what proportion could be confirmed as pneumococcal infections. A direct comparison was made in a group of patients who each had both tests performed. The Binax NOW S. pneumoniae urine antigen test was positive in 51 of 58 bacteremic pneumococcal cases (sensitivity, 88%; 95% confidence interval [CI], 77 to 95%), whereas the dual PCR was positive in 31 cases (sensitivity, 53.5%; 95% CI, 40 to 67%; P < 0.0001), and all of these had detectable urinary antigens. Both tests gave positive results in 2 of 51 control patients (referred to as other-organism septicemia), giving a specificity of 96% (95% CI, 86.5 to 99.5%). In 77 patients with nonbacteremic community-acquired pneumonia, urinary antigen was detected significantly more often (in 21 patients [27%]) than a positive result by the dual-PCR protocol (6 [8%]) (P = 0.002). The development of a dual-PCR protocol enhanced the sensitivity compared to that of the individual assays, but it is still significantly less sensitive than the Binax NOW urine antigen test, as well as being more time-consuming and expensive. Urinary antigen detection is the nonculture diagnostic method of choice for patients with possible severe pneumococcal infection.
PMCID: PMC2668348  PMID: 19225103
4.  Determination of antibodies to pneumococcal C polysaccharide in patients with community-acquired pneumonia. 
Journal of Clinical Microbiology  1985;22(5):808-814.
The pneumococcal C polysaccharide (PnC) is species specific and believed to be a cell wall component of all capsular types. Antibodies against PnC in human sera have been demonstrated previously, but the question of whether a rise in these antibodies occurs during pneumococcal infections has not been investigated. We used an indirect enzyme-linked immunosorbent assay (ELISA) for the estimation of PnC antibodies in 124 hospital-treated patients with pneumonia. In 3 of 6 patients with pneumococcal bacteremia and in 17 of 44 patients with S. pneumoniae isolated in the blood, sputum, or nasopharynx, a significant rise in antibody levels was recorded, accounting for a sensitivity of 38.6%. Of 35 patients with pneumonia of other known or suspected etiology, 1 gave a positive result, corresponding to a specificity of 97.1%. In addition, 3 of 8 patients with PnC antigen in the sputum as the only etiological finding and 5 of 37 patients with unknown etiology gave positive results. The PnC antibodies did not seem to have any protective capacity against pneumonia caused by pneumococci. The ELISA, in which only one antigen preparation was used, was more simple than other tests in which traditional capsular antigen preparations are used. It might therefore be used as a supplemental method in the diagnosis of pneumococcal pneumonia. The problems involved in expressing serum titers obtained with the ELISA are discussed.
PMCID: PMC268532  PMID: 4056007
5.  Performance of a Pneumolysin Enzyme-Linked Immunosorbent Assay for Diagnosis of Pneumococcal Infections▿  
Journal of Clinical Microbiology  2007;45(11):3549-3554.
A pneumolysin-specific enzyme-linked immunosorbent assay (PLY-ELISA) for the detection of pneumolysin in urine was developed and evaluated in comparison with the commercially available Binax Now Streptococcus pneumoniae test (Binax, Portland, ME) for the diagnosis of pneumococcal infections. Assay sensitivity was evaluated using urine from 108 patients with culture-confirmed pneumococcal infections. In adults, the sensitivity and specificity of the PLY-ELISA were 56.6% and 92.2%, respectively. In children with nasopharyngeal pneumococcal carriage, PLY-ELISA and Binax Now S. pneumoniae test sensitivities were 62.5% and 87.5%, respectively, while specificities were 94.4% and 27.8%, respectively. In children with nonnasopharyngeal pneumococcal carriage, PLY-ELISA and Binax Now S. pneumoniae test sensitivities were 68.7% and 93.7%, respectively, and test specificities were 94.1% and 41.2%, respectively. The persistence of pneumolysin in urine of pneumococcal pneumonia patients decreased significantly after 4 to 6 days of treatment. Our data suggest that combining the high specificity of the PLY-ELISA with the high sensitivity of the Binax Now S. pneumoniae test would enable pneumococcal infections to be accurately diagnosed in children.
PMCID: PMC2168496  PMID: 17728474
6.  Dual function of pneumolysin in the early pathogenesis of murine pneumococcal pneumonia. 
Journal of Clinical Investigation  1995;95(1):142-150.
Streptococcus pneumoniae is one of the most common etiologic agents of community-acquired pneumonia, particularly bacteremic pneumonia. Pneumolysin, a multifunctional cytotoxin, is a putative virulence factor for S. pneumoniae; however, a direct role for pneumolysin in the early pathogenesis of pneumococcal pneumonia has not been confirmed in vivo. We compared the growth of a pneumolysin-deficient (PLY[-]) type 2 S. pneumoniae strain with its isogenic wild-type strain (PLY[+]) after direct endotracheal instillation of bacteria into murine lungs. Compared with PLY(-) bacteria, infection with PLY(+) bacteria produced greater injury to the alveolar-capillary barrier, as assayed by albumin concentrations in alveolar lavage, and substantially greater numbers of PLY(+) bacteria were recovered in alveolar lavages and lung homogenates at 3 and 6 h after infection. The presence of pneumolysin also contributed to the development of bacteremia, which was detected at 3 h after intratracheal instillation of PLY(+) bacteria. The direct effects of pneumolysin on lung injury and on the ability of pneumococci to evade local lung defenses was confirmed by addition of purified recombinant pneumolysin to inocula of PLY(-) pneumococci, which promoted growth of PLY(-) bacteria in the lung to levels comparable to those seen with the PLY(+) strain. We further demonstrated the contributions of both the cytolytic and the complement-activating properties of pneumolysin on enhanced bacterial growth in murine lungs using genetically modified pneumolysin congeners and genetically complement-deficient mice. Thus, pneumolysin facilitates intraalveolar replication of pneumococci, penetration of bacteria from alveoli into the interstitium of the lung, and dissemination of pneumococci into the bloodstream during experimental pneumonia. Moreover, both the cytotoxic and the complement-activating activities of pneumolysin may contribute independently to the acute pulmonary injury and the high rates of bacteremia which characterize pneumococcal pneumonia.
PMCID: PMC295392  PMID: 7814608
7.  Validation of an Immunodiagnostic Assay for Detection of 13 Streptococcus pneumoniae Serotype-Specific Polysaccharides in Human Urine 
To improve the clinical diagnosis of pneumococcal infection in bacteremic and nonbacteremic community-acquired pneumonia (CAP), a Luminex technology-based multiplex urinary antigen detection (UAD) diagnostic assay was developed and validated. The UAD assay can simultaneously detect 13 different serotypes of Streptococcus pneumoniae by capturing serotype-specific S. pneumoniae polysaccharides (PnPSs) secreted in human urine. Assay specificity is achieved by capturing the polysaccharides with serotype-specific monoclonal antibodies (MAbs) on spectrally unique microspheres. Positivity for each serotype was based on positivity cutoff values calculated from a standard curve run on each assay plate together with positive- and negative-control urine samples. The assay is highly specific, since significant signals are detected only when each PnPS was paired with its homologous MAb-coated microspheres. Validation experiments demonstrated excellent accuracy and precision. The UAD assay and corresponding positivity cutoff values were clinically validated by assessing 776 urine specimens obtained from patients with X-ray-confirmed CAP. The UAD assay demonstrated 97% sensitivity and 100% specificity using samples obtained from patients with bacteremic, blood culture-positive CAP. Importantly, the UAD assay identified Streptococcus pneumoniae (13 serotypes) in a proportion of individuals with nonbacteremic CAP, a patient population for which the pneumococcal etiology of CAP was previously difficult to assess. Therefore, the UAD assay provides a specific, noninvasive, sensitive, and reproducible tool to support vaccine efficacy as well as epidemiological evaluation of pneumococcal disease, including CAP, in adults.
PMCID: PMC3416073  PMID: 22675155
8.  Association between Respiratory Syncytial Virus Activity and Pneumococcal Disease in Infants: A Time Series Analysis of US Hospitalization Data 
PLoS Medicine  2015;12(1):e1001776.
Daniel Weinberger and colleagues examine a possible interaction between two serious respiratory infections in children under 2 years of age.
Please see later in the article for the Editors' Summary
The importance of bacterial infections following respiratory syncytial virus (RSV) remains unclear. We evaluated whether variations in RSV epidemic timing and magnitude are associated with variations in pneumococcal disease epidemics and whether changes in pneumococcal disease following the introduction of seven-valent pneumococcal conjugate vaccine (PCV7) were associated with changes in the rate of hospitalizations coded as RSV.
Methods and Findings
We used data from the State Inpatient Databases (Agency for Healthcare Research and Quality), including >700,000 RSV hospitalizations and >16,000 pneumococcal pneumonia hospitalizations in 36 states (1992/1993–2008/2009). Harmonic regression was used to estimate the timing of the average seasonal peak of RSV, pneumococcal pneumonia, and pneumococcal septicemia. We then estimated the association between the incidence of pneumococcal disease in children and the activity of RSV and influenza (where there is a well-established association) using Poisson regression models that controlled for shared seasonal variations. Finally, we estimated changes in the rate of hospitalizations coded as RSV following the introduction of PCV7. RSV and pneumococcal pneumonia shared a distinctive spatiotemporal pattern (correlation of peak timing: ρ = 0.70, 95% CI: 0.45, 0.84). RSV was associated with a significant increase in the incidence of pneumococcal pneumonia in children aged <1 y (attributable percent [AP]: 20.3%, 95% CI: 17.4%, 25.1%) and among children aged 1–2 y (AP: 10.1%, 95% CI: 7.6%, 13.9%). Influenza was also associated with an increase in pneumococcal pneumonia among children aged 1–2 y (AP: 3.2%, 95% CI: 1.7%, 4.7%). Finally, we observed a significant decline in RSV-coded hospitalizations in children aged <1 y following PCV7 introduction (−18.0%, 95% CI: −22.6%, −13.1%, for 2004/2005–2008/2009 versus 1997/1998–1999/2000). This study used aggregated hospitalization data, and studies with individual-level, laboratory-confirmed data could help to confirm these findings.
These analyses provide evidence for an interaction between RSV and pneumococcal pneumonia. Future work should evaluate whether treatment for secondary bacterial infections could be considered for pneumonia cases even if a child tests positive for RSV.
Please see later in the article for the Editors' Summary
Editors' Summary
Respiratory infections—bacterial and viral infections of the lungs and the airways (the tubes that take oxygen-rich air to the lungs)—are major causes of illness and death in children worldwide. Pneumonia (infection of the lungs) alone is responsible for about 15% of all child deaths. The leading cause of bacterial pneumonia in children is Streptococcus pneumoniae, which is transmitted through contact with infected respiratory secretions. S. pneumoniae usually causes noninvasive diseases such as bronchitis, but sometimes the bacteria invade the lungs, the bloodstream, or the covering of the brain, where they cause pneumonia, septicemia, or meningitis, respectively. These potentially fatal invasive pneumococcal diseases can be treated with antibiotics but can also be prevented by vaccination with pneumococcal conjugate vaccines such as PCV7. The leading cause of viral pneumonia is respiratory syncytial virus (RSV), which is also readily transmitted through contact with infected respiratory secretions. Almost all children have an RSV infection before their second birthday—RSV usually causes a mild cold-like illness. However, some children infected with RSV develop pneumonia and have to be admitted to hospital for supportive care such as the provision of supplemental oxygen; there is no specific treatment for RSV infection.
Why Was This Study Done?
Co-infections with bacteria and viruses can sometimes have a synergistic effect and lead to more severe disease than an infection with either type of pathogen (disease-causing organism) alone. For example, influenza infections increase the risk of invasive pneumococcal disease. But does pneumococcal disease also interact with RSV infection? It is important to understand the interaction between pneumococcal disease and RSV to improve the treatment of respiratory infections in young children, but the importance of bacterial infections following RSV infection is currently unclear. Here, the researchers undertake a time series analysis of US hospitalization data to investigate the association between RSV activity and pneumococcal disease in infants. Time series analysis uses statistical methods to analyze data collected at successive, evenly spaced time points.
What Did the Researchers Do and Find?
For their analysis, the researchers used data collected between 1992/1993 and 2008/2009 by the State Inpatient Databases on more than 700,000 hospitalizations for RSV and more than 16,000 hospitalizations for pneumococcal pneumonia or septicemia among children under two years old in 36 US states. Using a statistical technique called harmonic regression to measure seasonal variations in disease incidence (the rate of occurrence of new cases of a disease), the researchers show that RSV and pneumococcal pneumonia shared a distinctive spatiotemporal pattern over the study period. Next, using Poisson regression models (another type of statistical analysis), they show that RSV was associated with significant increases (increases unlikely to have happened by chance) in the incidence of pneumococcal disease. Among children under one year old, 20.3% of pneumococcal pneumonia cases were associated with RSV activity; among children 1–2 years old, 10.1% of pneumococcal pneumonia cases were associated with RSV activity. Finally, the researchers report that following the introduction of routine vaccination in the US against S. pneumoniae with PCV7 in 2000, there was a significant decline in hospitalizations for RSV among children under one year old.
What Do These Findings Mean?
These findings provide evidence for an interaction between RSV and pneumococcal pneumonia and indicate that RSV is associated with increases in the incidence of pneumococcal pneumonia, particularly in young infants. Notably, the finding that RSV hospitalizations declined after the introduction of routine pneumococcal vaccination suggests that some RSV hospitalizations may have a joint viral–bacterial etiology (cause), although it is possible that PCV7 vaccination reduced the diagnosis of RSV because fewer children were hospitalized with pneumococcal disease and subsequently tested for RSV. Because this is an ecological study (an observational investigation that looks at risk factors and outcomes in temporally and geographically defined populations), these findings do not provide evidence for a causal link between hospitalizations for RSV and pneumococcal pneumonia. The similar spatiotemporal patterns for the two infections might reflect another unknown factor shared by the children who were hospitalized for RSV or pneumococcal pneumonia. Moreover, because pooled hospitalization discharge data were used in this study, these results need to be confirmed through analysis of individual-level, laboratory-confirmed data. Importantly, however, these findings support the initiation of studies to determine whether treatment for bacterial infections should be considered for children with pneumonia even if they have tested positive for RSV.
Additional Information
Please access these websites via the online version of this summary at
The US National Heart, Lung, and Blood Institute provides information about the respiratory system and about pneumonia
The US Centers for Disease Control and Prevention provides information on all aspects of pneumococcal disease and pneumococcal vaccination, including personal stories and information about RSV infection
The UK National Health Service Choices website provides information about pneumonia (including a personal story) and about pneumococcal diseases
KidsHealth, a website provided by the US-based non-profit Nemours Foundation, includes information on pneumonia and on RSV (in English and Spanish)
MedlinePlus provides links to other resources about pneumonia, RSV infections, and pneumococcal infections (in English and Spanish)
HCUPnet provides aggregated hospitalization data from the State Inpatient Databases used in this study
PMCID: PMC4285401  PMID: 25562317
9.  Bacterial Cytolysin during Meningitis Disrupts the Regulation of Glutamate in the Brain, Leading to Synaptic Damage 
PLoS Pathogens  2013;9(6):e1003380.
Streptococcus pneumoniae (pneumococcal) meningitis is a common bacterial infection of the brain. The cholesterol-dependent cytolysin pneumolysin represents a key factor, determining the neuropathogenic potential of the pneumococci. Here, we demonstrate selective synaptic loss within the superficial layers of the frontal neocortex of post-mortem brain samples from individuals with pneumococcal meningitis. A similar effect was observed in mice with pneumococcal meningitis only when the bacteria expressed the pore-forming cholesterol-dependent cytolysin pneumolysin. Exposure of acute mouse brain slices to only pore-competent pneumolysin at disease-relevant, non-lytic concentrations caused permanent dendritic swelling, dendritic spine elimination and synaptic loss. The NMDA glutamate receptor antagonists MK801 and D-AP5 reduced this pathology. Pneumolysin increased glutamate levels within the mouse brain slices. In mouse astrocytes, pneumolysin initiated the release of glutamate in a calcium-dependent manner. We propose that pneumolysin plays a significant synapto- and dendritotoxic role in pneumococcal meningitis by initiating glutamate release from astrocytes, leading to subsequent glutamate-dependent synaptic damage. We outline for the first time the occurrence of synaptic pathology in pneumococcal meningitis and demonstrate that a bacterial cytolysin can dysregulate the control of glutamate in the brain, inducing excitotoxic damage.
Author Summary
Bacterial meningitis is one of the most devastating brain diseases. Among the bacteria that cause meningitis, Streptococcus pneumoniae is the most common. Meningitis predominantly affects children, especially in the Third World, and most of them do not survive. Those that do survive often suffer permanent brain damage and hearing problems. The exact morphological substrates of brain damage in Streptococcus pneumoniae meningitis remain largely unknown. In our experiments, we found that the brain cortex of patients with meningitis demonstrated a loss of synapses (the contact points among neurons, responsible for the processes of learning and memory), and we identified the major pneumococcal neurotoxin pneumolysin as a sufficient cause of this loss. The effect was not direct but was mediated by the brain neurotransmitter glutamate, which was released upon toxin binding by one of the non-neuronal cell types of the brain – the astrocytes. Pneumolysin initiated calcium influx in astrocytes and subsequent glutamate release. Glutamate damaged the synapses via NMDA-receptors – a mechanism similar to the damage occurring in brain ischemia. Thus, we show that synaptic loss is present in pneumococcal meningitis, and we identify the toxic bacterial protein pneumolysin as the major factor in this process. These findings alter our understanding of bacterial meningitis and establish new therapeutic strategies for this fatal disease.
PMCID: PMC3681734  PMID: 23785278
10.  Quantitative relationship between anticapsular antibody measured by enzyme-linked immunosorbent assay or radioimmunoassay and protection of mice against challenge with Streptococcus pneumoniae serotype 4. 
Infection and Immunity  1990;58(12):3871-3876.
We have recently shown that a substantial proportion of antibody to pneumococcal polysaccharide as measured by enzyme-linked immunosorbent assay (ELISA) or radioimmunoassay is removed by adsorption with pneumococcal cell wall polysaccharide (CWPS). The present study was undertaken to validate the hypothesis that only serotype-specific antibody that remains after adsorption with CWPS provides protection against pneumococcal infection. Serum samples were obtained from human subjects before and after they had been vaccinated with pneumococcal polysaccharide vaccine. Antibody to Streptococcus pneumoniae serotype 4 was measured by ELISA without adsorption or after adsorption of serum with CWPS. Groups of mice were injected with graded doses of serum and then challenged intraperitoneally with 10, 100, or 1,000 50% lethal doses (LD50) of S. pneumoniae serotype 4. Without adsorption, prevaccination sera from five healthy adults appeared to contain up to 33 micrograms of antibody to S. pneumoniae serotype 4 antigen per ml; adsorption with CWPS removed all detectable antibody, and pretreating mice with up to 0.1 ml of these sera (less than or equal to 3.3 micrograms of antibody) failed to protect them against challenge with 100 LD50. In contrast, postvaccination sera contained 2.9 to 30 micrograms of antibody per ml that was not removed by adsorption. Diluting sera to administer desired amounts of serotype-specific immunoglobulin G showed a significant relationship between protection and antibody remaining after adsorption (P less than 0.05 by linear regression analysis); 150 ng was uniformly protective against 1,000 LD50, and 50 ng was protective against 100 LD50. These studies have, for the first time, quantitated the amount of serotype-specific antibody that protects mice against challenge with S. pneumoniae type 4. In light of these observations, it is necessary to reassess current concepts regarding the presence of antipneumococcal antibody in the unvaccinated population, responses to pneumococcal vaccination, and protective levels of immunoglobulin G.
PMCID: PMC313748  PMID: 2254015
11.  Nasopharyngeal antibodies to pneumococcal pneumolysin in children with acute otitis media. 
Pneumolysin, an intracellular protein toxin of all clinically relevant pneumococcal serotypes, is released in vivo during the autolysis of pneumococci and is believed to pave the way for intact pneumococci to invade and cause disease. Therefore, antibodies to pneumolysin should prevent its destructive function. We measured antibodies to pneumococcal pneumolysin in acute- and convalescent-phase nasopharyngeal aspirate samples of 120 children (median age, 2.5 years) with acute otitis media by enzyme immunoassay. Nasopharyngeal immunoglobulin M (IgM) and IgG class antibodies to pneumolysin were rarely detectable, whereas IgA class antibody was detected often, occurred independently of serum IgA antibody in serum, and correlated with the presence of the secretory component in pneumococcal antibody, indicating local production of IgA antibodies. Nasopharyngeal IgA antibody to pneumolysin was detected in 93% of the children already in the acute phase of otitis. Twenty percent of the children developed at least a threefold rise in the pneumolysin-specific IgA antibody concentration by the convalescent phase of otitis, with the youngest at 6 months of age, regardless of the pneumococcal findings in the nasopharynx or middle ear fluid. We suggest that nasopharyngeal IgA antibody to pneumolysin can be produced early in life by pneumococcal colonization.
PMCID: PMC170225  PMID: 8574834
12.  Diagnosis of Invasive Pneumococcal Infection by Serotype-Specific Urinary Antigen Detection 
Journal of Clinical Microbiology  2005;43(10):4972-4976.
Widespread use of conjugate pneumococcal polysaccharide-protein vaccines may alter the spectrum of pneumococci producing invasive disease. Novel sensitive diagnostic methods would be valuable for monitoring the epidemiology of pneumococcal disease within populations and vaccine recipients. Ideally, these methods should allow determination of the serotype of the infecting clone. Serotype-specific enzyme-linked immunosorbent assays (ELISA) for 13 capsular polysaccharides (types 1, 3, 4, 5, 6A, 6B, 7A, 9V, 14, 18C, 19A, 19F, and 23F) were developed. Experiments with pure capsular polysaccharide demonstrated that the assays were sensitive (0.01 to 1.0 ng/ml) and specific. These assays were used to detect capsular polysaccharide in urine from 263 adult patients with proven (blood culture-positive) invasive pneumococcal disease and pneumonia of unknown etiology and from patients with positive blood cultures yielding bacteria other than pneumococci (control group). Among 76 patients with invasive pneumococcal disease from whom blood culture isolates had been serotyped, 62 (82%) had infections with pneumococci of serotypes represented in the ELISA panel. Capsular antigen matching the serotype of the blood culture isolate was detected in the urine of 52 of these patients, giving a sensitivity of 83.9% for the target serotypes. The tests were significantly more sensitive for urine from patients with pneumococcal pneumonia (89.8%) than for urine from patients with nonpneumonic invasive infection (61.5%; P < 0.05). Data from the control group indicated a specificity of 98.8%. These assays should prove valuable in epidemiological investigation of invasive pneumococcal infection in adults, particularly if combined with a sensitive C-polysaccharide detection assay to screen for positive samples.
PMCID: PMC1248490  PMID: 16207950
13.  Avidity, Potency, and Cross-Reactivity of Monoclonal Antibodies to Pneumococcal Capsular Polysaccharide Serotype 6B 
Infection and Immunity  2001;69(1):336-344.
Many pneumococcal capsular polysaccharides (PSs) are similar in structure, and a pneumococcal antibody often binds to all of the PSs with a similar structure. Yet, these cross-reactive antibodies may bind to the structurally related pneumococcal capsular PSs with an avidity too low to be effective. If memory B cells producing such weakly cross-reactive antibodies are elicited with pneumococcal conjugate vaccines, the memory cells for low-avidity antibodies could compromise the subsequent immune responses to the cross-reactive PS (original antigenic sin). To investigate these issues, we produced 14 hybridomas secreting monoclonal antibodies (MAbs) to the capsular PS of Streptococcus pneumoniae serotype 6B by immunizing BALB/c mice with antigens containing 6B PS and studied their epitope, avidity, in vitro opsonizing capacity, in vivo protective capacity, and “antigen binding titer” by enzyme-linked immunosorbent assay (ELISA) of 6A and 6B capsular PSs. Six MAbs bound to the non-cross-reactive 6B-specific epitope, and seven MAbs bound to the cross-reactive epitope present in both 6A and 6B PSs One MAb (Hyp6BM6) revealed a novel epitope. This epitope was found on 6A PS in solution, but not on 6A PS adsorbed onto the plastic surface of the ELISA plates. The avidity of the MAb for 6A or 6B PS ranged from 7.8 × 106 M−1 to 4.1 × 1011 M−1. No MAbs were weakly cross-reactive, since none of the cross-reactive MAbs showed any tendency toward having less avidity to 6A PS (the cross-reactive PS) than to 6B PS. Avidity influenced the results of several antibody assays. When all of the hybridomas were examined, avidity strongly correlated with the titer of a unit amount of MAb to bind antigen-coated ELISA plates (r = 0.91) or to opsonize pneumococci in vitro (r = −0.85). Because both assay results are avidity dependent, the ELISA and the opsonization assay results were strongly correlated (r = 0.91), regardless of avidity. Avidity also correlated with the potency of a MAb to passively protect mice against pneumococcal infections. When only the immunoglobulin G hybridomas were examined, little increase in opsonizing capacity and in vivo protective potency was observed above 109 M−1. Taken together, an ELISA measuring antigen binding titer may be an adequate measure of the protective immunity induced with pneumococcal vaccines, and the absence of a partially cross-reactive MAb suggests that antigenic sin may not be significant in responses to vaccines against the S. pneumoniae 6B serotype.
PMCID: PMC97888  PMID: 11119522
14.  Evaluation of a PCR Assay for Detection of Streptococcus pneumoniae in Respiratory and Nonrespiratory Samples from Adults with Community-Acquired Pneumonia 
Streptococcus pneumoniae is the most common cause of community-acquired pneumonia, but it is undoubtedly underdiagnosed. We used a nested PCR assay (targeting the pneumolysin gene) to detect S. pneumoniae DNA in multiple sample types from 474 adults with community-acquired pneumonia and 183 control patients who did not have pneumonia. Plasma or buffy coat samples were PCR positive in only 6 of the 21 patients with positive blood cultures for S. pneumoniae and in 12 other patients (4 of whom had no other laboratory evidence of S. pneumoniae infection). Buffy coat samples from two control patients (neither having evidence of S. pneumoniae infection), but no control plasma samples, were PCR positive. Although pneumococcal antigen was detected in the urine from 120 of 420 (29%) patients, only 4 of 227 (2%) urine samples tested were PCR positive. Overall, 256 of 318 (81%) patients had PCR-positive sputum samples, including 58 of 59 samples from which S. pneumoniae was cultured. Throat swab samples from 229 of 417 (55%) patients were PCR positive and, in those who produced sputum, 96% also had positive PCR results from sputum. Throat swabs from 73 of 126 (58%) control patients were also PCR positive. We conclude that the pneumolysin PCR assay adds little to existing diagnostic tests for S. pneumoniae and is unable to distinguish colonization from infection when respiratory samples are tested.
PMCID: PMC149569  PMID: 12517826
15.  Age-Specific Immunoglobulin G (IgG) and IgA to Pneumococcal Protein Antigens in a Population in Coastal Kenya  
Infection and Immunity  2004;72(6):3331-3335.
Streptococcus pneumoniae is the primary etiological agent of community-acquired pneumonia and a major cause of meningitis and bacteremia. Three conserved pneumococcal proteins—pneumolysin, pneumococcal surface adhesin A (PsaA), and pneumococcal surface protein A (PspA)—are currently being investigated as vaccine candidates. Such protein-based vaccines, if proven effective, could provide a cheaper alternative to conjugate vaccine formulae. Few data from sub-Saharan Africa exist concerning the development of natural antibody to these antigens, however. To investigate the age-specific development of antiprotein immunoglobulin G (IgG) and IgA antibody responses, the sera of 220 persons 2 weeks to 84 years of age from coastal Kenya were assayed using enzyme-linked immunosorbent assays. IgG and IgA antibody responses to each antigen were observed in all age groups. Serum concentrations of IgG and IgA antibody responses to PspA and PdB (a recombinant toxoid derivative of pneumolysin), but not to PsaA, increased significantly with age (P < 0.001). No decline was observed in the sera of the elderly. Anti-protein IgG concentrations were only weakly correlated (0.30 < r < 0.56; P < 0.0001), as were IgA concentrations (0.24 < r < 0.54; P < 0.0001).
PMCID: PMC415695  PMID: 15155637
16.  Comparison of latex agglutination and counterimmunoelectrophoresis for the detection of pneumococcal antigen in elderly pneumonia patients. 
Journal of Clinical Microbiology  1985;22(4):553-557.
A Streptococcus pneumoniae latex agglutination (LA) test (Bactigen; Wampole Laboratories, Div. Carter-Wallace, Inc., Cranbury, N.J.) and counterimmunoelectrophoresis (CIE) were compared for the detection of pneumococcal antigen in serum and urine specimens from 68 elderly patients with pneumococcal pneumonia. The cases were categorized according to the presumptive role of S. pneumoniae: definite, putative, questionable (poor score), or questionable (mixed flora). Serum and urine samples were collected on days 1 to 3, 4 to 6, and 7 to 9 of illness and screened in parallel by LA and CIE. LA detected pneumococcal antigen in the serum or urine or both from 31 (46%) of the 68 pneumococcal pneumonia cases compared with 10 (15%) of cases detected by CIE. The highest rates of detection were noted in the 17 definite (bacteremic) cases: 88% by LA and 38% by CIE. The detection rates for both tests were lower in the other nonbacteremic pneumonia categories. Pneumococcal antigen was detected more often in urine specimens than in serum specimens by LA and CIE and was detected in the urine of 92 and 46% of definite cases, respectively, after 7 to 9 days of illness despite antibiotic therapy. Both tests were specific when tested with nonpneumococcal pneumonia cases, but LA detected pneumococcal antigen in two of seven chronic bronchitis cases. This study suggests that LA is as specific and more sensitive than CIE and is useful for detecting antigen in the elderly with proven bacteremic pneumococcal pneumonia. LA is less sensitive for detecting nonbacteremic pneumococcal pneumonia and, therefore, would be of limited value in the care and study of the institutionalized elderly.
PMCID: PMC268466  PMID: 4077966
17.  Influenza and Pneumococcal Vaccinations for Patients With Chronic Obstructive Pulmonary Disease (COPD) 
Executive Summary
In July 2010, the Medical Advisory Secretariat (MAS) began work on a Chronic Obstructive Pulmonary Disease (COPD) evidentiary framework, an evidence-based review of the literature surrounding treatment strategies for patients with COPD. This project emerged from a request by the Health System Strategy Division of the Ministry of Health and Long-Term Care that MAS provide them with an evidentiary platform on the effectiveness and cost-effectiveness of COPD interventions.
After an initial review of health technology assessments and systematic reviews of COPD literature, and consultation with experts, MAS identified the following topics for analysis: vaccinations (influenza and pneumococcal), smoking cessation, multidisciplinary care, pulmonary rehabilitation, long-term oxygen therapy, noninvasive positive pressure ventilation for acute and chronic respiratory failure, hospital-at-home for acute exacerbations of COPD, and telehealth (including telemonitoring and telephone support). Evidence-based analyses were prepared for each of these topics. For each technology, an economic analysis was also completed where appropriate. In addition, a review of the qualitative literature on patient, caregiver, and provider perspectives on living and dying with COPD was conducted, as were reviews of the qualitative literature on each of the technologies included in these analyses.
The Chronic Obstructive Pulmonary Disease Mega-Analysis series is made up of the following reports, which can be publicly accessed at the MAS website at:
Chronic Obstructive Pulmonary Disease (COPD) Evidentiary Framework
Influenza and Pneumococcal Vaccinations for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Smoking Cessation for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Community-Based Multidisciplinary Care for Patients With Stable Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Pulmonary Rehabilitation for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Long-term Oxygen Therapy for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Noninvasive Positive Pressure Ventilation for Acute Respiratory Failure Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Noninvasive Positive Pressure Ventilation for Chronic Respiratory Failure Patients With Stable Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Hospital-at-Home Programs for Patients with Acute Exacerbations of Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Home Telehealth for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Cost-Effectiveness of Interventions for Chronic Obstructive Pulmonary Disease Using an Ontario Policy Model
Experiences of Living and Dying With COPD: A Systematic Review and Synthesis of the Qualitative Empirical Literature
For more information on the qualitative review, please contact Mita Giacomini at:
For more information on the economic analysis, please visit the PATH website:
The Toronto Health Economics and Technology Assessment (THETA) collaborative has produced an associated report on patient preference for mechanical ventilation. For more information, please visit the THETA website:
The objective of this analysis was to determine the effectiveness of the influenza vaccination and the pneumococcal vaccination in patients with chronic obstructive pulmonary disease (COPD) in reducing the incidence of influenza-related illness or pneumococcal pneumonia.
Clinical Need: Condition and Target Population
Influenza Disease
Influenza is a global threat. It is believed that the risk of a pandemic of influenza still exists. Three pandemics occurred in the 20th century which resulted in millions of deaths worldwide. The fourth pandemic of H1N1 influenza occurred in 2009 and affected countries in all continents.
Rates of serious illness due to influenza viruses are high among older people and patients with chronic conditions such as COPD. The influenza viruses spread from person to person through sneezing and coughing. Infected persons can transfer the virus even a day before their symptoms start. The incubation period is 1 to 4 days with a mean of 2 days. Symptoms of influenza infection include fever, shivering, dry cough, headache, runny or stuffy nose, muscle ache, and sore throat. Other symptoms such as nausea, vomiting, and diarrhea can occur.
Complications of influenza infection include viral pneumonia, secondary bacterial pneumonia, and other secondary bacterial infections such as bronchitis, sinusitis, and otitis media. In viral pneumonia, patients develop acute fever and dyspnea, and may further show signs and symptoms of hypoxia. The organisms involved in bacterial pneumonia are commonly identified as Staphylococcus aureus and Hemophilus influenza. The incidence of secondary bacterial pneumonia is most common in the elderly and those with underlying conditions such as congestive heart disease and chronic bronchitis.
Healthy people usually recover within one week but in very young or very old people and those with underlying medical conditions such as COPD, heart disease, diabetes, and cancer, influenza is associated with higher risks and may lead to hospitalization and in some cases death. The cause of hospitalization or death in many cases is viral pneumonia or secondary bacterial pneumonia. Influenza infection can lead to the exacerbation of COPD or an underlying heart disease.
Streptococcal Pneumonia
Streptococcus pneumoniae, also known as pneumococcus, is an encapsulated Gram-positive bacterium that often colonizes in the nasopharynx of healthy children and adults. Pneumococcus can be transmitted from person to person during close contact. The bacteria can cause illnesses such as otitis media and sinusitis, and may become more aggressive and affect other areas of the body such as the lungs, brain, joints, and blood stream. More severe infections caused by pneumococcus are pneumonia, bacterial sepsis, meningitis, peritonitis, arthritis, osteomyelitis, and in rare cases, endocarditis and pericarditis.
People with impaired immune systems are susceptible to pneumococcal infection. Young children, elderly people, patients with underlying medical conditions including chronic lung or heart disease, human immunodeficiency virus (HIV) infection, sickle cell disease, and people who have undergone a splenectomy are at a higher risk for acquiring pneumococcal pneumonia.
Influenza and Pneumococcal Vaccines
Trivalent Influenza Vaccines in Canada
In Canada, 5 trivalent influenza vaccines are currently authorized for use by injection. Four of these are formulated for intramuscular use and the fifth product (Intanza®) is formulated for intradermal use.
The 4 vaccines for intramuscular use are:
Fluviral (GlaxoSmithKline), split virus, inactivated vaccine, for use in adults and children ≥ 6 months;
Vaxigrip (Sanofi Pasteur), split virus inactivated vaccine, for use in adults and children ≥ 6 months;
Agriflu (Novartis), surface antigen inactivated vaccine, for use in adults and children ≥ 6 months; and
Influvac (Abbott), surface antigen inactivated vaccine, for use in persons ≥ 18 years of age.
FluMist is a live attenuated virus in the form of an intranasal spray for persons aged 2 to 59 years. Immunization with current available influenza vaccines is not recommended for infants less than 6 months of age.
Pneumococcal Vaccine
Pneumococcal polysaccharide vaccines were developed more than 50 years ago and have progressed from 2-valent vaccines to the current 23-valent vaccines to prevent diseases caused by 23 of the most common serotypes of S pneumoniae. Canada-wide estimates suggest that approximately 90% of cases of pneumococcal bacteremia and meningitis are caused by these 23 serotypes. Health Canada has issued licenses for 2 types of 23-valent vaccines to be injected intramuscularly or subcutaneously:
Pneumovax 23® (Merck & Co Inc. Whitehouse Station, NJ, USA), and
Pneumo 23® (Sanofi Pasteur SA, Lion, France) for persons 2 years of age and older.
Other types of pneumococcal vaccines licensed in Canada are for pediatric use. Pneumococcal polysaccharide vaccine is injected only once. A second dose is applied only in some conditions.
Research Questions
What is the effectiveness of the influenza vaccination and the pneumococcal vaccination compared with no vaccination in COPD patients?
What is the safety of these 2 vaccines in COPD patients?
What is the budget impact and cost-effectiveness of these 2 vaccines in COPD patients?
Research Methods
Literature search
Search Strategy
A literature search was performed on July 5, 2010 using OVID MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), the Cochrane Library, and the International Agency for Health Technology Assessment (INAHTA) for studies published from January 1, 2000 to July 5, 2010. The search was updated monthly through the AutoAlert function of the search up to January 31, 2011. Abstracts were reviewed by a single reviewer and, for those studies meeting the eligibility criteria, full-text articles were obtained. Articles with an unknown eligibility were reviewed with a second clinical epidemiologist and then a group of epidemiologists until consensus was established. Data extraction was carried out by the author.
Inclusion Criteria
studies comparing clinical efficacy of the influenza vaccine or the pneumococcal vaccine with no vaccine or placebo;
randomized controlled trials published between January 1, 2000 and January 31, 2011;
studies including patients with COPD only;
studies investigating the efficacy of types of vaccines approved by Health Canada;
English language studies.
Exclusion Criteria
non-randomized controlled trials;
studies investigating vaccines for other diseases;
studies comparing different variations of vaccines;
studies in which patients received 2 or more types of vaccines;
studies comparing different routes of administering vaccines;
studies not reporting clinical efficacy of the vaccine or reporting immune response only;
studies investigating the efficacy of vaccines not approved by Health Canada.
Outcomes of Interest
Primary Outcomes
Influenza vaccination: Episodes of acute respiratory illness due to the influenza virus.
Pneumococcal vaccination: Time to the first episode of community-acquired pneumonia either due to pneumococcus or of unknown etiology.
Secondary Outcomes
rate of hospitalization and mechanical ventilation
mortality rate
adverse events
Quality of Evidence
The quality of each included study was assessed taking into consideration allocation concealment, randomization, blinding, power/sample size, withdrawals/dropouts, and intention-to-treat analyses. The quality of the body of evidence was assessed as high, moderate, low, or very low according to the GRADE Working Group criteria. The following definitions of quality were used in grading the quality of the evidence:
Summary of Efficacy of the Influenza Vaccination in Immunocompetent Patients With COPD
Clinical Effectiveness
The influenza vaccination was associated with significantly fewer episodes of influenza-related acute respiratory illness (ARI). The incidence density of influenza-related ARI was:
All patients: vaccine group: (total of 4 cases) = 6.8 episodes per 100 person-years; placebo group: (total of 17 cases) = 28.1 episodes per 100 person-years, (relative risk [RR], 0.2; 95% confidence interval [CI], 0.06−0.70; P = 0.005).
Patients with severe airflow obstruction (forced expiratory volume in 1 second [FEV1] < 50% predicted): vaccine group: (total of 1 case) = 4.6 episodes per 100 person-years; placebo group: (total of 7 cases) = 31.2 episodes per 100 person-years, (RR, 0.1; 95% CI, 0.003−1.1; P = 0.04).
Patients with moderate airflow obstruction (FEV1 50%−69% predicted): vaccine group: (total of 2 cases) = 13.2 episodes per 100 person-years; placebo group: (total of 4 cases) = 23.8 episodes per 100 person-years, (RR, 0.5; 95% CI, 0.05−3.8; P = 0.5).
Patients with mild airflow obstruction (FEV1 ≥ 70% predicted): vaccine group: (total of 1 case) = 4.5 episodes per 100 person-years; placebo group: (total of 6 cases) = 28.2 episodes per 100 person-years, (RR, 0.2; 95% CI, 0.003−1.3; P = 0.06).
The Kaplan-Meier survival analysis showed a significant difference between the vaccinated group and the placebo group regarding the probability of not acquiring influenza-related ARI (log-rank test P value = 0.003). Overall, the vaccine effectiveness was 76%. For categories of mild, moderate, or severe COPD the vaccine effectiveness was 84%, 45%, and 85% respectively.
With respect to hospitalization, fewer patients in the vaccine group compared with the placebo group were hospitalized due to influenza-related ARIs, although these differences were not statistically significant. The incidence density of influenza-related ARIs that required hospitalization was 3.4 episodes per 100 person-years in the vaccine group and 8.3 episodes per 100 person-years in the placebo group (RR, 0.4; 95% CI, 0.04−2.5; P = 0.3; log-rank test P value = 0.2). Also, no statistically significant differences between the 2 groups were observed for the 3 categories of severity of COPD.
Fewer patients in the vaccine group compared with the placebo group required mechanical ventilation due to influenza-related ARIs. However, these differences were not statistically significant. The incidence density of influenza-related ARIs that required mechanical ventilation was 0 episodes per 100 person-years in the vaccine group and 5 episodes per 100 person-years in the placebo group (RR, 0.0; 95% CI, 0−2.5; P = 0.1; log-rank test P value = 0.4). In addition, no statistically significant differences between the 2 groups were observed for the 3 categories of severity of COPD. The effectiveness of the influenza vaccine in preventing influenza-related ARIs and influenza-related hospitalization was not related to age, sex, severity of COPD, smoking status, or comorbid diseases.
Overall, significantly more patients in the vaccine group than the placebo group experienced local adverse reactions (vaccine: 17 [27%], placebo: 4 [6%]; P = 0.002). Significantly more patients in the vaccine group than the placebo group experienced swelling (vaccine 4, placebo 0; P = 0.04) and itching (vaccine 4, placebo 0; P = 0.04). Systemic reactions included headache, myalgia, fever, and skin rash and there were no significant differences between the 2 groups for these reactions (vaccine: 47 [76%], placebo: 51 [81%], P = 0.5).
With respect to lung function, dyspneic symptoms, and exercise capacity, there were no significant differences between the 2 groups at 1 week and at 4 weeks in: FEV1, maximum inspiratory pressure at residual volume, oxygen saturation level of arterial blood, visual analogue scale for dyspneic symptoms, and the 6 Minute Walking Test for exercise capacity.
There was no significant difference between the 2 groups with regard to the probability of not acquiring total ARIs (influenza-related and/or non-influenza-related); (log-rank test P value = 0.6).
Summary of Efficacy of the Pneumococcal Vaccination in Immunocompetent Patients With COPD
Clinical Effectiveness
The Kaplan-Meier survival analysis showed no significant differences between the group receiving the penumoccocal vaccination and the control group for time to the first episode of community-acquired pneumonia due to pneumococcus or of unknown etiology (log-rank test 1.15; P = 0.28). Overall, vaccine efficacy was 24% (95% CI, −24 to 54; P = 0.33).
With respect to the incidence of pneumococcal pneumonia, the Kaplan-Meier survival analysis showed a significant difference between the 2 groups (vaccine: 0/298; control: 5/298; log-rank test 5.03; P = 0.03).
Hospital admission rates and median length of hospital stays were lower in the vaccine group, but the difference was not statistically significant. The mortality rate was not different between the 2 groups.
Subgroup Analysis
The Kaplan-Meier survival analysis showed significant differences between the vaccine and control groups for pneumonia due to pneumococcus and pneumonia of unknown etiology, and when data were analyzed according to subgroups of patients (age < 65 years, and severe airflow obstruction FEV1 < 40% predicted). The accumulated percentage of patients without pneumonia (due to pneumococcus and of unknown etiology) across time was significantly lower in the vaccine group than in the control group in patients younger than 65 years of age (log-rank test 6.68; P = 0.0097) and patients with a FEV1 less than 40% predicted (log-rank test 3.85; P = 0.0498).
Vaccine effectiveness was 76% (95% CI, 20−93; P = 0.01) for patients who were less than 65 years of age and −14% (95% CI, −107 to 38; P = 0.8) for those who were 65 years of age or older. Vaccine effectiveness for patients with a FEV1 less than 40% predicted and FEV1 greater than or equal to 40% predicted was 48% (95% CI, −7 to 80; P = 0.08) and −11% (95% CI, −132 to 47; P = 0.95), respectively. For patients who were less than 65 years of age (FEV1 < 40% predicted), vaccine effectiveness was 91% (95% CI, 35−99; P = 0.002).
Cox modelling showed that the effectiveness of the vaccine was dependent on the age of the patient. The vaccine was not effective in patients 65 years of age or older (hazard ratio, 1.53; 95% CI, 0.61−a2.17; P = 0.66) but it reduced the risk of acquiring pneumonia by 80% in patients less than 65 years of age (hazard ratio, 0.19; 95% CI, 0.06−0.66; P = 0.01).
No patients reported any local or systemic adverse reactions to the vaccine.
PMCID: PMC3384373  PMID: 23074431
18.  Streptococcus pneumoniae Translocates into the Myocardium and Forms Unique Microlesions That Disrupt Cardiac Function 
PLoS Pathogens  2014;10(9):e1004383.
Hospitalization of the elderly for invasive pneumococcal disease is frequently accompanied by the occurrence of an adverse cardiac event; these are primarily new or worsened heart failure and cardiac arrhythmia. Herein, we describe previously unrecognized microscopic lesions (microlesions) formed within the myocardium of mice, rhesus macaques, and humans during bacteremic Streptococcus pneumoniae infection. In mice, invasive pneumococcal disease (IPD) severity correlated with levels of serum troponin, a marker for cardiac damage, the development of aberrant cardiac electrophysiology, and the number and size of cardiac microlesions. Microlesions were prominent in the ventricles, vacuolar in appearance with extracellular pneumococci, and remarkable due to the absence of infiltrating immune cells. The pore-forming toxin pneumolysin was required for microlesion formation but Interleukin-1β was not detected at the microlesion site ruling out pneumolysin-mediated pyroptosis as a cause of cell death. Antibiotic treatment resulted in maturing of the lesions over one week with robust immune cell infiltration and collagen deposition suggestive of long-term cardiac scarring. Bacterial translocation into the heart tissue required the pneumococcal adhesin CbpA and the host ligands Laminin receptor (LR) and Platelet-activating factor receptor. Immunization of mice with a fusion construct of CbpA or the LR binding domain of CbpA with the pneumolysin toxoid L460D protected against microlesion formation. We conclude that microlesion formation may contribute to the acute and long-term adverse cardiac events seen in humans with IPD.
Author Summary
Hospitalization for community-acquired pneumonia carries a documented risk for adverse cardiac events. These occur during infection and contribute to elevated mortality rates in convalescent individuals up to 1 year thereafter. We describe a previously unrecognized pathogenic mechanism by which Streptococcus pneumoniae, the leading cause of community-acquired pneumonia, causes direct cardiotoxicity and forms microscopic bacteria-filled lesions within the heart. Microlesions were detected in experimentally infected mice and rhesus macaques, as well as in heart sections from humans who succumbed to invasive pneumococcal disease (IPD). Cardiac microlesion formation required interaction of the bacterial adhesin CbpA with host Laminin receptor and bacterial cell wall with Platelet-activating factor receptor. Microlesion formation also required the pore-forming toxin pneumolysin. When infected mice were rescued with antibiotics, we observed robust signs of collagen deposition at former lesion sites. Thus, microlesions and the scarring that occurs thereafter may explain why adverse cardiac events occur during and following IPD.
PMCID: PMC4169480  PMID: 25232870
19.  Screening of Pneumococcal Pneumonia by Amplification of Pneumolysin Gene in Children Visiting Hospitals in Lahore, Pakistan 
Iranian Journal of Pediatrics  2012;22(4):524-530.
Streptococcus pneumoniae is a common worldwide potential pathogen causing pneumonia among children and the detection of pneumococcal infections by conventional culturing techniques is cumbersome. The present study describes a comparative analysis of sensitive nested-PCR and bacterial culture in pediatric patients with clinical and radiological indication of S. pneumoniae infection.
PCR was performed using outer primers to amplify a 348-bp region and inner primers a 208-bp region of the pneumolysin gene. For pneumolysin PCR assay, DNA from peripheral blood and middle ear fluid (MEF) samples was extracted by salting out method. The sensitivity of the assay was evaluated with about 0.06 pg of purified S. pneumoniae genomic DNA.
Among 90 MEF culture negative samples from acute otitis media pediatric patients, 8.8% pneumolysin-PCR positivity was detected, demonstrating the sensitivity and reliability of PCR for rapid pneumonia evaluation. Binomial test of proportionality performed on (SPSS 17) gives P< 0.05 indicating that PCR technique is statistically significant and sensitive in the diagnosis of S. pneumoniae infection.
The research work evaluated the effectiveness and efficacy of nested-PCR for detecting S. pneumoniae in pediatric patients with clinical and radiological confirmation of bacterial infection. This simplified method permitted quick selection of the patients and played a significant role in preliminary management of pneumococcal infections.
PMCID: PMC3533155  PMID: 23430764
Streptococcus pneumoniae; PCR; Screening; Pneumolysin; Gene; Pneumococcal Infections
20.  Clinical Presentation, Processes and Outcomes of Care for Patients with Pneumococcal Pneumonia 
To describe the presentation, resolution of symptoms, processes of care, and outcomes of pneumococcal pneumonia, and to compare features of the bacteremic and nonbacteremic forms of this illness.
A prospective cohort study.
Five medical institutions in 3 geographic locations.
Inpatients and outpatients with community-acquired pneumonia (CAP).
Sociodemographic characteristics, respiratory and nonrespiratory symptoms, and physical examination findings were obtained from interviews or chart review. Severity of illness was assessed using a validated prediction rule for short-term mortality in CAP. Pneumococcal pneumonia was categorized as bacteremic; nonbacteremic, pure etiology; or nonbacteremic, mixed etiology.
One hundred fifty-eight (6.9%) of 2,287 patients (944 outpatients, 1,343 inpatients) with CAP had pneumococcal pneumonia. Sixty-five (41%) of the 158 with pneumococcal pneumonia were bacteremic; 74 (47%) were nonbacteremic with S. pneumoniae as sole pathogen; and 19 (12%) were nonbacteremic with S. pneumoniae as one of multiple pathogens. The pneumococcal bacteremia rate for outpatients was 2.6% and for inpatients it was 6.6%. Cough, dyspnea, and pleuritic pain were common respiratory symptoms. Hemopytsis occurred in 16% to 22% of the patients. A large number of nonrespiratory symptoms were noted. Bacteremic patients were less likely than nonbacteremic patients to have sputum production and myalgias (60% vs 82% and 33% vs 57%, respectively; P <.01 for both), more likely to have elevated blood urea nitrogen and serum creatinine levels, and more likely to receive pencillin therapy. Half of bacteremic patients were in the low risk category for short-term mortality (groups I to III), similar to the nonbacteremic patients. None of the 32 bacteremic patients in risk groups I to III died, while 7 of 23 (30%) in risk group V died. Intensive care unit admissions and pneumonia-related mortality were similar between bacteremic and nonbacteremic groups, although 46% of the bacteremic group had respiratory failure compared with 32% and 37% for the other groups. The nonbacteremic pure etiology patients returned to household activities faster than bacteremic patients. Symptoms frequently persisted at 30 days: cough (50%); dyspnea (53%); sputum production (48%); pleuritic pain (13%); and fatigue (63%).
There were few differences in the presentation of bacteremic and nonbacteremic pneumococcal pneumonia. About half of bacteremic pneumococcal pneumonia patients were at low risk for mortality. Symptom resolution frequently was slow.
PMCID: PMC1495594  PMID: 11029678
pneumonia; pneumococcal; outcomes
21.  Quantitative PCR Assay Using Sputum Samples for Rapid Diagnosis of Pneumococcal Pneumonia in Adult Emergency Department Patients 
Journal of Clinical Microbiology  2005;43(7):3221-3226.
Accurate diagnosis of pneumococcal pneumonia in the acute-care setting remains a challenge due to the inadequate sensitivity of conventional diagnostic tests. Sputum cultures, which are likely to have the highest diagnostic yields of all specimen types, have been considered unreliable, due to their inability to differentiate colonization from infection. Our objective was to evaluate the potential clinical utility of a rapid quantitative real-time PCR assay using sputum samples for Streptococcus pneumoniae in adult patients with community-acquired pneumonia (CAP). A prospective clinical observational study of consecutively enrolled emergency department patients with CAP was performed; only those patients with excess good-quality sputum samples were included for evaluation. Sputum samples were tested for the presence of S. pneumoniae by using a quantitative PCR that targets the pneumolysin gene. PCR findings were compared with those of a composite reference standard comprising Gram staining of sputum samples and sputum/blood cultures. The area under the curve (AUC) and a log-transformed threshold, which provides the maximal sensitivity and specificity, were calculated. Of 487 subjects enrolled, 129 were evaluable. Receiver operating characteristic curve analysis demonstrated an AUC of 0.87. Sensitivity and specificity were 90.0 percent and 80.0 percent, respectively; positive and negative predictive values were 58.7 percent and 96.2 percent, respectively. We have demonstrated that a quantitative rapid pneumolysin PCR assay has favorable accuracy for diagnosis of pneumococcal pneumonia in adult patients with CAP; this assay may be a useful diagnostic adjunct for clinicians, particularly those practicing in the acute-care setting, where rapid pathogen identification may assist in selection of the most appropriate antibiotics.
PMCID: PMC1169177  PMID: 16000439
22.  Pneumococcal capsular antigen detection and pneumococcal serology in patients with community acquired pneumonia. 
Thorax  1991;46(12):902-906.
BACKGROUND: Methods to determine the microbial cause of community acquired pneumonia include detection of pneumococcal antigen and measurement of pneumococcal capsular antibody response. Their usefulness compared with conventional microbiological techniques was investigated in patients with pneumonia, some of whom had been treated with antibiotics. METHODS: Pneumococcal capsular antigen was detected by latex agglutination in sputum and the results compared prospectively with results of conventional microbiological techniques in 90 patients with community acquired pneumonia. Serum, urine, and pleural fluid samples were also tested for antigen. Serum pneumococcal capsular antibody titres were measured. RESULTS: A diagnosis was established by conventional microbiological techniques in 53 patients, 30 of whom had pneumococcal pneumonia. The sensitivity of antigen detection in first day sputum specimens (n = 18) in those with pneumococcal pneumonia was 94%; antigen was present in 23 of the 27 patients who produced representative sputum on admission and during follow up. The specificity of antigen detection in sputum in patients with non-pneumococcal pneumonia and lung infarction was 87%. Antigen was present in 12 of 25 patients with pneumonia of unknown aetiology who produced representative sputum. Antigen was rarely detected in serum and urine, but was present in pleural fluid in three of four patients with pneumococcal pneumonia and in all four patients with pneumonia of unknown aetiology. Pneumococcal antigen remained detectable in patients treated with antibiotics. Pneumococcal capsular antibody detection was as specific (85%) as antigen detection, but had a lower sensitivity (50%). CONCLUSION: Pneumococcal antigen detection in sputum or pleural fluid is of value in making a rapid diagnosis and provides an additional diagnostic result in patients with pneumococcal pneumonia, especially those receiving antibiotic treatment.
PMCID: PMC463496  PMID: 1792638
23.  Use of a Rapid Test of Pneumococcal Colonization Density to Diagnose Pneumococcal Pneumonia 
In a prospective study, human immunodeficiency virus (HIV)–infected patients with pneumococcal pneumonia had nasopharyngeal colonization densities 5 log10 higher than those in concurrently identified HIV-infected asymptomatic controls, as measured by real-time polymerase chain reaction (rtPCR). A nasopharyngeal lytA density of ≥8000 copies/mL at rtPCR may be a useful diagnostic marker for pneumococcal pneumonia.
Background. There is major need for a more sensitive assay for the diagnosis of pneumococcal community-acquired pneumonia (CAP). We hypothesized that pneumococcal nasopharyngeal (NP) proliferation may lead to microaspiration followed by pneumonia. We therefore tested a quantitative lytA real-time polymerase chain reaction (rtPCR) on NP swab samples from patients with pneumonia and controls.
Methods. In the absence of a sensitive reference standard, a composite diagnostic standard for pneumococcal pneumonia was considered positive in South African human immunodeficiency virus (HIV)–infected adults hospitalized with radiographically confirmed CAP, if blood culture, induced good-quality sputum culture, Gram stain, or urinary Binax demonstrated pneumococci. Results of quantitative lytA rtPCR in NP swab samples were compared with quantitative colony counts in patients with CAP and 300 HIV-infected asymptomatic controls.
Results. Pneumococci were the leading pathogen identified in 76 of 280 patients with CAP (27.1%) using the composite diagnostic standard. NP colonization density measured by lytA rtPCR correlated with quantitative cultures (r = 0.67; P < .001). The mean lytA rtPCR copy number in patients with pneumococcal pneumonia was 6.0 log10 copies/mL, compared with patients with CAP outside the composite standard (2.7 log10 copies/mL; P < .001) and asymptomatic controls (0.8 log10 copies/mL; P < .001). A lytA rtPCR density ≥8000 copies/mL had a sensitivity of 82.2% and a specificity of 92.0% for distinguishing pneumococcal CAP from asymptomatic colonization. The proportion of CAP cases attributable to pneumococcus increased from 27.1% to 52.5% using that cutoff.
Conclusions. A rapid molecular assay of NP pneumococcal density performed on an easily available specimen may significantly increase pneumococcal pneumonia diagnoses in adults.
PMCID: PMC3275757  PMID: 22156852
24.  Prospective Study To Determine Clinical Relevance of Detection of Pneumococcal DNA in Sera of Children by PCR 
Journal of Clinical Microbiology  1998;36(3):669-673.
We undertook a prospective study to evaluate the accuracy of PCR of serum (aimed at the pneumococcal pneumolysin gene) at detecting pneumococcal infections in infants and children. The assay was positive for all blood and cerebrospinal fluid culture-positive samples and for 38 and 44% of patients with lobar pneumonia and acute otitis media, respectively. It was positive for 17% of healthy controls. There was a marked effect of age on the rate of positivity among healthy controls, with the highest rate (33%) being in 2-year-old children, the age group with the highest rate of nasopharyngeal (NP) carriage; the lowest rate was found among infants <2 months of age (13%) and adults ages 18 to 50 years (0%), age groups with the lowest NP pneumococcal carriage rates. Carriers of pneumococci in the nasopharynges had a higher rate of positivity than noncarriers of pneumococci in the nasopharynges for all groups. Our results suggest that although PCR of serum is a sensitive test for the detection of Streptococcus pneumoniae in sterile fluids, its high rate of positivity for healthy controls, related to NP pneumococcal carriage, might exclude it from being useful in detecting deep-seated pneumococcal infections.
PMCID: PMC104606  PMID: 9508293
25.  Estimating the Burden of Pneumococcal Pneumonia among Adults: A Systematic Review and Meta-Analysis of Diagnostic Techniques 
PLoS ONE  2013;8(4):e60273.
Pneumococcal pneumonia causes significant morbidity and mortality among adults. Given limitations of diagnostic tests for non-bacteremic pneumococcal pneumonia, most studies report the incidence of bacteremic or invasive pneumococcal disease (IPD), and thus, grossly underestimate the pneumococcal pneumonia burden. We aimed to develop a conceptual and quantitative strategy to estimate the non-bacteremic disease burden among adults with community-acquired pneumonia (CAP) using systematic study methods and the availability of a urine antigen assay.
Methods and Findings
We performed a systematic literature review of studies providing information on the relative yield of various diagnostic assays (BinaxNOW® S. pneumoniae urine antigen test (UAT) with blood and/or sputum culture) in diagnosing pneumococcal pneumonia. We estimated the proportion of pneumococcal pneumonia that is bacteremic, the proportion of CAP attributable to pneumococcus, and the additional contribution of the Binax UAT beyond conventional diagnostic techniques, using random effects meta-analytic methods and bootstrapping. We included 35 studies in the analysis, predominantly from developed countries. The estimated proportion of pneumococcal pneumonia that is bacteremic was 24.8% (95% CI: 21.3%, 28.9%). The estimated proportion of CAP attributable to pneumococcus was 27.3% (95% CI: 23.9%, 31.1%). The Binax UAT diagnosed an additional 11.4% (95% CI: 9.6, 13.6%) of CAP beyond conventional techniques. We were limited by the fact that not all patients underwent all diagnostic tests and by the sensitivity and specificity of the diagnostic tests themselves. We address these resulting biases and provide a range of plausible values in order to estimate the burden of pneumococcal pneumonia among adults.
Estimating the adult burden of pneumococcal disease from bacteremic pneumococcal pneumonia data alone significantly underestimates the true burden of disease in adults. For every case of bacteremic pneumococcal pneumonia, we estimate that there are at least 3 additional cases of non-bacteremic pneumococcal pneumonia.
PMCID: PMC3615022  PMID: 23565216

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