Amoebiasis is a major public health problem in tropical and subtropical countries. Although a number of antiamoebic agents are used for its treatment, yet the susceptibility data on clinical isolates of Entamoeba histolytica and Entamoeba dispar are not available. Therefore, the present study was aimed to assess the in vitro susceptibility of clinical isolates of E. histolytica and E. dispar to metronidazole, chloroquine, emetine and tinidazole.
A total of 45 clinical isolates (15 E. histolytica and 30 E. dispar) were maintained in polyxenic cultures followed by monoxenic cultures. In vitro drug sensitivity (IC50) of clinical isolates and standard reference strain of E. histolytica (HM1: IMSS) was assessed by nitro blue tetrazolium (NBT) reduction assay after exposure to various concentrations of each drug.
The results showed that all clinical isolates had a higher IC50 compared to reference strain to all the four drugs. E. histolytica isolates appeared to be more susceptible [IC50 (μm) 13.2,26.3,31.2 and 12.4] compared to E. dispar isolates [IC50(μm) 15.6,28.9,32.8 and 13.2] and the reference strain of E. histolytica [IC50 (μm) 9.5, 15.5, 29.9 and 10.2] to the metronidazole, chloroquine, emetine and tinidazole respectively.
The results indicate that till date, Entamoeba isolates in India do not seem to be resistant to the commonly used antiamoebic drugs.
Patients with cystic fibrosis [CF] have frequent pulmonary exacerbations associated with the isolation of bacterial organisms from sputum samples. It is not clear however, if there are differences in the types of additional organisms isolated from patients who are infected with Burkholderia cepacia complex [BCC] or Pseudomonas aerugionsa [PA] in comparison to those who are not infected with either of these organisms [NI].
Adult patients attending the regional CF unit were followed over a two year period and patients were assigned to three groups depending on whether they were known to be chronically infected with BCC, PA or NI. We compared the numbers and types of organisms which were isolated in each of these groups.
Information was available on a total of 79 patients; BCC 23, PA 30 and NI 26. Total numbers of organisms isolated, expressed as median and IQR for each group, [P = 0.045] and numbers of co-infecting organisms [P = 0.003] were significantly higher in the BCC group compared to PA, and in the PA group [P < 0.001, p = 0.007 respectively] compared to NI patients. The pattern of co-infecting organisms was similar in all three groups.
Total numbers of organisms isolated and numbers of co-infecting organisms were significantly higher in the BCC group compared to PA, and in the PA group compared to NI patients. Types of co-infecting organisms are similar in all groups of patients.
Cystic Fibrosis; Bacterial Infection; Antibiotics; Burkholderia cepacia complex; Pseudomonas aeruginosa
Helicobacter pylori diagnosis and susceptibility profile directs the applicability of recommended treatment regimens in our setting. To our knowledge, there is no published data on the culture and local susceptibility pattern of Helicobacter pylori in the Philippines.
52 dyspeptic adult patients undergoing endoscopy from the Outpatient Gastroenterology clinic of the University of the Philippines-Philippine General Hospital underwent multiple gastric biopsy and specimens were submitted for gram stain, culture, antimicrobial sensitivity testing, rapid urease test and histology. Antimicrobial susceptibility testing was done by Epsilometer testing (Etest) method against metronidazole, clarithromycin, amoxicillin, and tetracycline.
Sixty percent (60%) of the study population was positive for H. pylori infection (mean age of 44 years ± 13), 70% were males. H. pylori culture showed a sensitivity of 45% (95% CI [29.5–62.1]), specificity of 98% (95%CI [81.5–100%]), positive likelihood ratio of 19.93 (95% CI [1.254–317.04]) and a negative likelihood ratio of 0.56 (95% CI [0.406–0.772]). All H. pylori strains isolated were sensitive to metronidazole, clarithromycin, amoxicillin and tetracycline.
Knowledge of the antibiotic susceptibility patterns in our setting allows us to be more cautious in the choice of first-line agents. Information on antibiotic susceptibility profile plays an important role in empiric antibiotic treatment and management of refractive cases.
Nocardia brasiliensis is a rare human pathogen usually associated with localized cutaneous infections.
We report a case of primary lymphocutaneous Nocardia brasiliensis infection developed after a bone fracture of the left hand of an otherwise healthy 32-year-old man. Treatment with trimethoprim-sulfamethoxazole given for a total of three months combined with surgical debridement resulted in complete resolution of the infection.
Nocardiosis should be part of the differential diagnosis in patients with sporotrichoid infection, particularly those with a history of outdoor injury. Culture of the affected tissue and antimicrobial susceptibility testing of the isolate should be performed for diagnosis and treatment.
Ampicillin was selected to further study the effect of this antibiotic on the colonization capability of S. pneumoniae and L. fermentum intranasally inoculated in a mice experimental model. The sensitivity of S. pneumoniae and L. fermentum to antibiotics was evaluated by different "in vitro" techniques. The results showed that both microorganisms have a typical pattern of sensitivity to antibiotics in these assays. The "in vivo" experiments showed that the treatment with Ampicillin increased the number of lactobacilli and neumococci in the groups of mice treated only with one of the microorganisms. In those mice treated with Lactobacillus, challenged later with neumococci and treated with Ampicillin, the pathogen in lung decreased on the 4th day, disappearing completely after on. The histological studies showed that the antibiotic treatment decreased the inflammatory response produced by the pathogen at the lung and trachea levels.
S. pneumoniae; L. fermentum; probiotics; Ampicillin; antimicrobials; colonization
Personal Digital Assistants (PDAS) are rapidly becoming popular tools in the assistance of managing hospitalized patients, but little is known about how often expert recommendations are available for the treatment of infectious diseases in hospitalized patients.
To determine how often PDAs could provide expert recommendations for the management of infectious diseases in patients admitted to a general medicine teaching service.
Prospective observational cohort study
Internal medicine resident teaching service at an urban hospital in Dayton, Ohio
212 patients (out of 883 patients screened) were identified with possible infectious etiologies as the cause for admission to the hospital.
Patients were screened prospectively from July 2002 until October 2002 for infectious conditions as the cause of their admissions. 5 PDA programs were assessed in October 2002 to see if treatment recommendations were available for managing these patients. The programs were then reassessed in January 2004 to evaluate how the latest editions of the software would perform under the same context as the previous year.
PDAs provided treatment recommendations in at least one of the programs for 100% of the patients admitted over the 4 month period in the 2004 evaluation. Each of the programs reviewed improved from 2002 to 2004, with five of the six programs offering treatment recommendations for over 90% of patients in the study.
Current PDA software provides expert recommendations for a great majority of general internal medicine patients presenting to the hospital with infectious conditions.
Pseudomonas aeruginosa (PA) is the most important bacterial pathogen in patients with cystic fibrosis (CF) patients. Currently, routine bacteriological culture on selective/non- selective culture media is the cornerstone of microbiological detection. The aim of this study was to compare isolation rates of PA by conventional culture and molecular (PCR) detection directly from sputum.
Adult patients (n = 57) attending the regional adult CF centre in Northern Ireland, provided fresh sputum following airways clearance exercise. Following processing of the specimen with sputasol (1:1 vol), the specimen was examined for the presence of PA by plating onto a combination of culture media (Pseudomonas isolation agar, Blood agar & McConkey agar). In addition, from the same specimen, genomic bacterial DNA was extracted (1 ml) and was amplified employing two sequence-specific targets, namely (i) the outer membrane protein (oprL) gene locus and (ii) the exotoxin A (ETA) gene locus.
By sputum culture, there were 30 patients positive for PA, whereas by molecular techniques, there were 35 positive patients. In 39 patients (22 PA +ve & 17 PA -ve), there was complete agreement between molecular and conventional detection and with both PCR gene loci. The oprL locus was more sensitive than the ETA locus, as the former was positive in 10 more patients and there were no patients where the ETA was positive and the oprL target negative. Where a PCR +ve/culture -ve result was recorded (10 patients), we followed these patients and recorded that 5 of these patients converted to being culture-positive at times ranging from 4–17 months later, with a mean lag time of 4.5 months.
This study indicates that molecular detection of PA in sputum employing the oprL gene target, is a useful technique in the early detection of PA, gaining on average 4.5 months over conventional culture. It now remains to be established whether aggressive antibiotic intervention at this earlier stage, based on PCR detection, has any significant benefits on clinical outcome.
Emphysematous cystitis is a rare disease entity caused by gas fermenting bacterial and fungal pathogens. Clinical symptoms are nonspecific and diagnostic clues often arise from the unanticipated imaging findings. We report a case of 52-year-old male who presented with fever, dysuria and gross hematuria who was found to have emphysematous cystitis.
hematuria; emphysematous cystitis
Tuberculosis continues to be an important health problem in the world. Besides pulmonary involvement extrapulmonary involvement becomes an affair in developing countries, even in developed countries.
A thirty-six year old male patient was admitted with abdominal pain, diarrhea, nausea, vomiting and fever which had started one week before. The patient had been followed up with predialisis Chronic Renal Failure(CRF) diagnosis for 4 years and receiving continuous ambulatory peritoneal dialysis (CAPD) treatment for 4 months. In peritoneal fluid, 1600/mm3 cells were detected and 70% of them were polymorphonuclear leukocytosis. The patient begun nonspesific antibiotherapy but no benefit was obtained after 12 days and peritoneal fluid bacterial cultures remained negative. Peritoneal smear was positive for Asid-fast basilli (AFB), and antituberculosis therapy was started with isoniazid, rifampicine, ethambutol and pyrazinamide. After 15 days his peritoneal fluid cell count was decreased and his symptoms were relieved. Peritoneal fluid tuberculosis culture was found positive.
Considering this case, we think that in patients with CAPD catheter and peritonitis; when peritoneal fluid leukocytes are high and PMNL are dominant, AFB and tuberculosis culture must be investigated besides bacterial culture routinely.
CAPD; Tuberculosis peritonitis; Asid-fast basilli(AFB); Tuberculin skin test
Mycobacterium avium are ubiquitous environmental organisms and a cause of disseminated infection in patients with end-stage AIDS. The glycopeptidolipids (GPL) of M. avium are proposed to participate in the pathogenesis of this organism, however, establishment of a clear role for GPL in disease production has been limited by the inability to genetically manipulate M. avium.
To be able to study the role of the GPL in M. avium pathogenesis, a ts-sacB selection system, not previously used in M. avium, was employed as a means to achieve homologous recombination for the rhamnosyltransferase (rtfA) gene of a pathogenic serovar 8 strain of M. avium to prevent addition of serovar-specific sugars to rhamnose of the fatty acyl-peptide backbone of GPL. The genotype of the resultant rtfA mutant was confirmed by polymerase chain reaction and southern hybridization. Disruption in the proximal sugar of the haptenic oligosaccharide resulted in the loss of serovar specific GPL with no change in the pattern of non-serovar specific GPL moieties as shown by thin layer chromatography and gas chromatography/mass spectrometry. Complementation of wild type (wt) rtfA in trans through an integrative plasmid restored serovar-8 specific GPL expression identical to wt serovar 8 parent strain.
In this study, we affirm our results that rtfA encodes an enzyme responsible for the transfer of Rha to 6d-Tal and provide evidence of a second allelic exchange mutagenesis system suitable for M. avium.
We report the second allelic exchange system for M. avium utilizing ts-sacB as double-negative and xylE as positive counter-selection markers, respectively. This system of allelic exchange would be especially useful for M. avium strains that demonstrate significant isoniazid (INH) resistance despite transformation with katG. Through the construction of mutants in GPL or other mycobacterial components, their roles in M. avium pathogenesis, biosynthesis, or drug resistance can be studied in a consistent manner.
To determine the frequency, risk factors and mortality of nosocomial pneumonia a prospective study was conducted in the intensive care units. In the study period, 2402 patients were included. The nosocomial pneumonia was defined according to the Centers for Disease Control Criteria. Overall, 163 (6.8%) of the patients developed nosocomial pneumonia and 75.5% (n = 123) of all patients with nosocomial pneumonia were ventilator-associated pneumonia. 163 patients who were admitted to the intensive care unit during the same period but had no bacteriologic or histologic evidence of pneumonia were used as a control group. The APACHE II score, coma, hypoalbuminemia, mechanical ventilation, tracheotomy, presence of nasogastric tube were found as independent risk factors. Crude and attributable mortality were 65% and 52.6%, respectively. The mortality rate was five times greater in the cases (OR: 5.2; CI 95%: 3.2–8.3). The mean length of stay in the intensive care unit and hospital in the cases were longer than controls (p < 0.0001). Patients requiring mechanical ventilation have a high frequency of nosocomial pneumonia.
Hospital infections; ventilator-associated pneumonia; death rates
Although various hematologic abnormalities are seen in tuberculosis, immune thrombocytopenic purpura is a rare event.
We report a case of a 29 year-old male who was presented with immune thrombocytopenia-induced hemoptysis, macroscopic hematuria and generalized petechiae. The patient was found to have clinical, microbiological and radiological evidence of active pulmonary tuberculosis. The immune thrombocytopenic purpura was successfully treated with anti-tuberculous drugs combined with corticosteroids and high dose immune globulin therapy.
Immune thrombocytopenic purpura can be one of the hematological manifestations of tuberculosis which has a global prevalence with increasing incidence secondary to HIV infection.
Tuberculosis; immune thrombocytopenic purpura; immune thrombocytopenia
Increasing antimicrobial resistance among the key pathogens responsible for community-acquired respiratory tract infections has the potential to limit the effectiveness of antibiotics available to treat these infections. Since there are regional differences in the susceptibility patterns observed and treatment is frequently empirical, the selection of antibiotic therapy may be challenging. PROTEKT, a global, longitudinal multicentre surveillance study, tracks the activity of telithromycin and comparator antibacterial agents against key respiratory tract pathogens.
In this analysis, we examine the prevalence of antibacterial resistance in 1,336 bacterial pathogens, isolated from adult and paediatric patients clinically diagnosed with acute bacterial sinusitis (ABS).
Results and discussion
In total, 58.0%, 66.1%, and 55.8% of S. pneumoniae isolates were susceptible to penicillin, cefuroxime, and clarithromycin respectively. Combined macrolide resistance and reduced susceptibility to penicillin was present in 200/640 (31.3 %) of S. pneumoniae isolates (128 isolates were resistant to penicillin [MIC >= 2 mg/L], 72 intermediate [MIC 0.12–1 mg/L]) while 99.5% and 95.5% of isolates were susceptible to telithromycin and amoxicillin-clavulanate, respectively. In total, 88.2%, 87.5%, 99.4%, 100%, and 100% of H. influenzae isolates were susceptible to ampicillin, clarithromycin, cefuroxime, telithromycin, and amoxicillin-clavulanate, respectively. In vitro, telithromycin demonstrated the highest activity against M. catarrhalis (MIC50 = 0.06 mg/L, MIC90 = 0.12 mg/L).
The high in vitro activity of against pathogens commonly isolated in ABS, together with a once daily dosing regimen and clinical efficacy with 5-day course of therapy, suggest that telithromycin may play a role in the empiric treatment of ABS.
Globally ICUs are encountering emergence and spread of antibiotic-resistant pathogens and for some pathogens there are few therapeutic options available.
Antibiotic in vitro susceptibility data of predominant ICU pathogens during 2000–2 were analyzed using data from The Surveillance Network (TSN) Databases in Europe (France, Germany and Italy), Canada, and the United States (US).
Oxacillin resistance rates among Staphylococcus aureus isolates ranged from 19.7% to 59.4%. Penicillin resistance rates among Streptococcus pneumoniae varied from 2.0% in Germany to as high as 20.2% in the US; however, ceftriaxone resistance rates were comparably lower, ranging from 0% in Germany to 3.4% in Italy. Vancomycin resistance rates among Enterococcus faecalis were ≤ 4.5%; however, among Enterococcus faecium vancomycin resistance rates were more frequent ranging from 0.8% in France to 76.3% in the United States. Putative rates of extended-spectrum β-lactamase (ESBL) production among Enterobacteriaceae were low, <6% among Escherichia coli in the five countries studied. Ceftriaxone resistance rates were generally lower than or similar to piperacillin-tazobactam for most of the Enterobacteriaceae species examined. Fluoroquinolone resistance rates were generally higher for E. coli (6.5% – 13.9%), Proteus mirabilis (0–34.7%), and Morganella morganii (1.6–20.7%) than other Enterobacteriaceae spp (1.5–21.3%). P. aeruginosa demonstrated marked variation in β-lactam resistance rates among countries. Imipenem was the most active compound tested against Acinetobacter spp., based on resistance rates.
There was a wide distribution in resistance patterns among the five countries. Compared with other countries, Italy showed the highest resistance rates to all the organisms with the exception of Enterococcus spp., which were highest in the US. This data highlights the differences in resistance encountered in intensive care units in Europe and North America and the need to determine current local resistance patterns by which to guide empiric antimicrobial therapy for intensive care infections.
Intensive-care unit; antibiotic susceptibility
Resistance to β-lactam antibiotics in enteric Gram-negative bacilli may be difficult to detect using standard methods of either Kirby-Bauer disc diffusion (KBDD) or broth dilution for minimal inhibitory concentration (MIC). This difficulty is due to genetic differences in resistance determinants, differences in levels of gene expression, and variation in spectra of enzymatic activity against the substrate β-lactams used for susceptibility testing. We have examined 95 clinical isolates reportedly susceptible to ceftazidime and ceftriaxone, as originally determined by either KBDD or MIC methods. The organisms studied here were isolated in 2002 from two pediatric hospital centers (Seattle, USA and Shanghai, China). They belong to the inducible β-lactamase producing Gram-negative bacilli, such as Enterobacter spp., Citrobacter spp., Serratia spp., Morganella spp., Providencia spp., and Proteus vulgaris. A Kirby-Bauer disc approximation (KBDA) method identified inducible phenotypes of third-generation cephalosporin resistance in 76% of isolates, which would otherwise be considered susceptible by standard KBDD methods.
Class 1 integrons contain genetic elements for site-specific recombination, capture and mobilization of resistance genes. Studies investigating the prevalence, distribution and types of integron located resistance genes are important for surveillance of antimicrobial resistance and to understand resistance development at the molecular level.
We determined the prevalence and genetic content of class 1 integrons in Enterobacteriaceae (strain collection 1, n = 192) and E. coli (strain collection 2, n = 53) from bloodstream infections in patients from six Norwegian hospitals by molecular techniques. Class 1 integrons were also characterized in 54 randomly selected multiresistant E. coli isolates from gastrointestinal human infections (strain collection 3).
Class 1 integrons were present in 10.9% of the Enterobacteriaceae blood culture isolates of collection 1, all but one (S. Typhi) being E. coli. Data indicated variations in class 1 integron prevalence between hospitals. Class 1 integrons were present in 37% and 34% of the resistant blood culture isolates (collection 1 and 2, respectively) and in 42% of the resistant gastrointestinal E. coli. We detected a total of 10 distinct integron cassette PCR amplicons that varied in size between 0.15 kb and 2.2 kb and contained between zero and three resistance genes. Cassettes encoding resistance to trimethoprim and aminoglycosides were most common. We identified and characterized a novel plasmid-located integron with a cassette-bound novel gene (linF) located downstream of an aadA2 gene cassette. The linF gene encoded a putative 273 aa lincosamide nucleotidyltransferase resistance protein and conferred resistance to lincomycin and clindamycin. The deduced LinF amino acid sequence displayed approximately 35% identity to the Enterococcus faecium and Enterococcus faecalis nucleotidyl transferases encoded by linB and linB'
The present study demonstrated an overall low and stable prevalence of class 1 integron gene cassettes in clinical Enterobacteriaceae and E. coli isolates in Norway. Characterization of the novel lincosamide resistance gene extends the growing list of class 1 integron gene cassettes that confer resistance to an increasing number of antibiotics.
Upper respiratory tract infections (URTIs) are among the most frequent reasons for physician office visits in paediatrics. Despite their predominant viral aetiology, URTIs continue to be treated with antimicrobials. We explored general practitioners' (GPs) prescribing behaviour for antimicrobials in children (≤ 16 years) with URTIs in Trinidad, using the guidelines from the Centers for Disease Control and Prevention (CDC) as a reference.
A cross-sectional study was conducted on 92 consenting GPs from the 109 contacted in Central and East Trinidad, between January to June 2003. Using a pilot-tested questionnaire, GPs identified the 5 most frequent URTIs they see in office and reported on their antimicrobial prescribing practices for these URTIs to trained research students.
The 5 most frequent URTIs presenting in children in general practice, are the common cold, pharyngitis, tonsillitis, sinusitis and acute otitis media (AOM) in rank order. GPs prescribe at least 25 different antibiotics for these URTIs with significant associations for amoxicillin, co-amoxiclav, cefaclor, cefuroxime, erythromycin, clarithromycin and azithromycin (p < 0.001). Amoxicillin alone or with clavulanate was the most frequently prescribed antibiotic for all URTIs. Prescribing variations from the CDC recommendations were observed for all URTIs except for AOM (50%), the most common condition for antibiotics. Doctors practicing for >30 years were more likely to prescribe antibiotics for the common cold (p = 0.014). Severity (95.7%) and duration of illness (82.5%) influenced doctors' prescribing and over prescribing in general practice was attributed to parent demands (75%) and concern for secondary bacterial infections (70%). Physicians do not request laboratory investigations primarily because they are unnecessary (86%) and the waiting time for results is too long (51%).
Antibiotics are over prescribed for paediatric URTIs in Trinidad and amoxicillin with co-amoxiclav were preferentially prescribed. Except for AOM, GPs' prescribing varied from the CDC guidelines for drug and duration. Physicians recognise antibiotics are overused and consider parents expecting antibiotics and a concern for secondary bacterial infections are prescribing pressures. Guidelines to manage URTIs, ongoing surveillance programs for antibiotic resistance, public health education on non-antibiotic strategies, and postgraduate education for rational pharmacotherapy in general practice would decrease inappropriate antibiotic use in URTIs.
Mycobacterium bovis BCG vaccine significantly reduces the risk of tuberculosis by 50% and continues to be used to prevent tuberculosis around the world. However, it has been shown to be ineffective in some geographical regions. The existence of different BCG strains was described more than 60 years ago, these vary in their antigenic content but the genetic mutations in BCG strains have yet been shown to affect their protection. After the declaration of tuberculosis as a global emergency in 1993, current research attempts to develop a novel more-effective vaccine. Using new technologies, recombinant, auxotroph, DNA, subunit and phylogenetically closely related mycobacteria, naturally or genetically attenuated, have been used as vaccines in animal models, but their protective efficacy, is less than that offered by the current BCG vaccine. Today it is mandatory that a major effort be made to understand how different BCG vaccine strains influence immune response and why in some cases vaccines have failed, so we can rationally develop the next generation of tuberculosis vaccines to reduce the prevalence from 10% to less than 2 % for developed countries.
Aim of the study was to determine the clinical efficacy of a new antiseptic liquid soap (Stellisept® scrub), based on the combination of undecylenamidopropyltrimonium methosulphate (4%) and phenoxyethanol (2%), for eradication of MRSA among colonized patients who do not receive antibiotic therapy.
Over two years 50 MRSA patients in 6 hospitals were observed. Treatment was defined as the daily application of Stellisept scrub for the antiseptic body and hair wash (at least 60 s) in combination with nasal mupirocin. A treatment cycle was a minimum of 5 days treatment. Screening was carried out at least 48 h after the treatment cycle was finished, with 24 h between each of the requested three or more samplings, which included the nasopharynx, groin, axilla, perineum and other MRSA-positive skin areas.
Fifteen cases were retrospectively excluded (lack of outcome documentation, concomitant antibiotic therapy, open wounds). All 35 patients had colonization with MRSA before antiseptic treatment on the skin, in the groin (80%), the axilla (25.7%), the perineum (20%) or other skin areas (14.3%). Colonization at more than one skin sites was found in 34.3%. Nasal colonization was found in 21 of 28 patients (75%), 7 patients were without nasal screening prior to the antiseptic treatment. After one treatment cycle MRSA was eradicated in 25 patients (71.4%), after a second cycle the total eradication rate was 91.4%, after a third cycle the rate increased to 94.2%. No patient discontinued the antiseptic treatment due to dermal intolerance of the product.
Progressive eradication of MRSA carriage was observed with the antiseptic soap and mupirocin. The eradication rate was not biased by concomitant antibiotic treatment, screening during treatment or lack of evidence for colonization in contrast to other studies with other preparations.
There is limited data available on the environmental and public health impact of the microbiological hazards associated with sputa from patients with cystic fibrosis [CF]. Pseudomonas aeruginosa, Burkholderia cenocepacia (formerly Burkholderia cepacia genomovar III), Staphylococcus aureus and Stenotrophomonas maltophilia are bacterial pathogens which are commonly found in the sputum of CF patients. A study was performed to ascertain the amount of sputum produced relating to microbial loading, as well as the diversity of bacteria present in a population of adult patients, with particular attention to pathogenic organisms.
Sputum from adult [>18 years old] CF patients [n = 20], chosen randomly from a population of 138 CF patients, was collected over a 24 h period on admission to the in-patient CF unit and enumerated quantitatively, as well as the sputa from 138 adult CF patients was examined qualitatively for the presence of infecting microflora. In addition, all different phenotypes from the sputum of each patient were identified phenotypically employing a combination of conventional identification methods [e.g. oxidase], as well as the API Identification schemes [API 20 NE, API 20 E].
This study demonstrated that patients with cystic fibrosis generate large numbers of bacteria in their sputum, approximating to 109 organisms per patient per day. Although these organisms are introduced to the environment from the respiratory tract mainly via sputum, relatively few represent true bacterial pathogens and therefore are not clinically important to the general public who are immunocompotent. The greatest risk of such environmental microbial loading is to other patients with CF and therefore CF patients should be made aware of the hazards of acquiring such organisms from the environment, as well as socializing with other CF patients with certain transmissible types, such as Pseudomonas aeruginosa and Burkholderia cenocepacia.
Environmental health professionals should therefore be aware that CF patients are a greater risk to their peer grouping rather than to the general public or health care workers and that good personal hygiene practices with CF patients should be encouraged to minimize environmental contamination and potential acquistion.
Bloodstream infections are associated with significant patient morbidity and mortality. Antimicrobial susceptibility patterns should guide the choice of empiric antimicrobial regimens for patients with bacteremia.
From January to December of 2002, 82,569 bacterial blood culture isolates were reported to The Surveillance Network (TSN) Database-USA by 268 laboratories. Susceptibility to relevant antibiotic compounds was analyzed using National Committee for Clinical Laboratory Standards guidelines.
Coagulase-negative staphylococci (42.0%), Staphylococcus aureus (16.5%), Enterococcus faecalis (8.3%), Escherichia coli (7.2%), Klebsiella pneumoniae (3.6%), and Enterococcus faecium (3.5%) were the most frequently isolated bacteria from blood cultures, collectively accounting for >80% of isolates. In vitro susceptibility to expanded-spectrum β-lactams such as ceftriaxone were high for oxacillin-susceptible coagulase-negative staphylococci (98.7%), oxacillin-susceptible S. aureus (99.8%), E. coli (97.3%), K. pneumoniae (93.3%), and Streptococcus pneumoniae (97.2%). Susceptibilities to fluoroquinolones were variable for K. pneumoniae (90.3–91.4%), E. coli (86.0–86.7%), oxacillin-susceptible S. aureus (84.0–89.4%), oxacillin-susceptible coagulase-negative staphylococci (72.7–82.7%), E. faecalis (52.1%), and E. faecium (11.3%). Combinations of antimicrobials are often prescribed as empiric therapy for bacteremia. Susceptibilities of all blood culture isolates to one or both agents in combinations of ceftriaxone, ceftazdime, cefepime, piperacillin-tazobactam or ciprofloxacin plus gentamicin were consistent (range, 74.8–76.3%) but lower than similar β-lactam or ciprofloxacin combinations with vancomycin (range, 93.5–96.6%).
Ongoing surveillance for antimicrobial susceptibility remains essential, and will enhance efforts to identify resistance and attempt to limit its spread.
One controversial source of infection for hepatitis C virus (HCV) involves the sharing of contaminated implements, such as straws or spoons, used to nasally inhale cocaine and other powdered drugs. An essential precondition for this mode of transmission is the presence of HCV in the nasal secretions of intranasal drug users.
Blood and nasal secretion samples were collected from five plasma-positive chronic intranasal drug users and tested for HCV RNA using RT-PCR.
HCV was detected in all five blood samples and in the nasal secretions of the subject with the highest serum viral load.
This study is the first to demonstrate the presence of HCV in nasal secretions. This finding has implications for potential transmission of HCV through contact with contaminated nasal secretions.
In streptococci, three macrolide resistance determinants (erm(B), erm(TR) and mef(A)) have been found. In addition, certain mutations at the ribosomal 23S RNA can cause resistance to macrolides. Mutation at the position 2058 of the 23S rRNA of the Streptococcus pyogenes as a cause of macrolide resistance has not been described before.
Antibiotic resistance determinations for the clinical S. pyogenes strain ni4277 were done using the agar dilution technique. Macrolide resistance mechanisms were studied by PCR and sequencing. All six rRNA operons were amplified using operon-specific PCR. The PCR products were partially sequenced in order to resolve the sequences of different 23S rRNA genes.
One clinical isolate of S. pyogenes carrying an adenine to guanine mutation at the position 2058 of the 23S rRNA in five of the six possible rRNA genes but having no other known macrolide resistance determinants is described. The strain was highly resistant to macrolides and azalides, having erythromycin and azithromycin MICs > 256 microgram/ml. It was resistant to lincosamides (clindamycin MIC 16 microgram/ml) and also MIC values for ketolides were clearly elevated. The MIC for telithromycin was 16 microgram/ml.
In this clinical S. pyogenes strain, a mutation at the position 2058 was detected. No other macrolide resistance-causing determinants were detected. This mutation is known to cause macrolide resistance in other bacteria. We can conclude that this mutation was the most probable cause of macrolide, lincosamide and ketolide resistance in this strain.
The aim of this study was to determine whether prior antimicrobial therapy is an important risk factor for extended antimicrobial therapy among critically ill children. To evaluate other predisposing factors influencing the usage of antibiotics in a pediatric intensive care unit (PICU) setting. To examine the relationship between the extent of antimicrobial treatment and the incidence of nosocomial infections and outcome.
This prospective observational cohort study was conducted at a university-affiliated teaching hospital (760 beds) in Athens. Clinical data were collected upon admission and on each consecutive PICU day. The primary reason for PICU admission was recorded using a modified classification for mutually exclusive disease categories. All administered antibiotics to the PICU patients were recorded during a six-month period. Microbiological and pharmacological data were also collected over this period. The cumulative per patient and the maximum per day numbers of administered antibiotics, as well as the duration of administration were related to the following factors: Number of antibiotics which the patients were already receiving the day before admission, age groups, place of origin, the severity of illness, the primary disease and its complications during the course of hospitalization, the development of nosocomial infections with positive cultures, the presence of chronic disease or immunodeficiency, various interventional techniques (mechanical ventilation, central catheters), and PICU outcome.
During a six-month period 174 patients were admitted to the PICU and received antibiotics for a total of 950 days (62.3% of the length of stay days). While in PICU, 34 patients did not receive antimicrobial treatment (19.5%), 69 received one antibiotic (39.7%), 42 two (24.1%), 17 three (9.8%), and 12 more than three (6.9%). The number of antibiotics prescribed in PICU or at discharge did not differ from that at admission. Indications for receiving antibiotics the day before admission and throughout during hospitalization into PICU were significantly correlated. Although the cumulative number of administered antibiotics did not correlate with mortality (9.8%), it was significantly related to the severity scoring systems PRISM (p < .001), TISS (p < .002) and was significantly related to the number of isolated microorganisms (p < .0001). Multiple regression analysis demonstrated that independent determinants of the cumulative number of antibiotics were: prior administration of antibiotics, presence of a bloodstream infection, positive bronchial cultures, immunodeficiency, and severity of illness.
Prior antimicrobial therapy should be recognized as an important risk factor for extended antimicrobial therapy among critically ill children. Severity of illness, immunodeficiency, and prolonged length of stay are additional risk factors.
Intensive care; severity of illness; nosocomial infections; resistance; surveillance cultures.
Bacterial infections of the central nervous system, especially acute infections such as bacterial meningitis require immediate, invariably empiric antibiotic therapy. The widespread emergence of resistance among bacterial species is a cause for concern. Current antibacterial susceptibility data among central nervous system (CNS) pathogens is important to define current prevalence of resistance.
Antimicrobial susceptibility of pathogens isolated from CNS specimens was analyzed using The Surveillance Database (TSN®) USA Database which gathers routine antibiotic susceptibility data from >300 US hospital laboratories. A total of 6029 organisms derived from CNS specimen sources during 2000–2002, were isolated and susceptibility tested.
Staphylococcus aureus (23.7%) and Streptococcus pneumoniae (11.0%) were the most common gram-positive pathogens. Gram-negative species comprised approximately 25% of isolates. The modal patient age was 1 or <1 year for most organisms. Prevalence of MRSA among S. aureus from cerebrospinal fluid (CSF) and brain abscesses were 29.9–32.9%. Penicillin resistance rates were 16.6% for S. pneumoniae, 5.3% for viridans group streptococci, and 0% for S. agalactiae. For CSF isolates, ceftriaxone resistance was S. pneumoniae (3.5%), E. coli (0.6%), Klebsiella pneumoniae (2.8%), Serratia marcescens (5.6%), Enterobacter cloacae (25.0%), Haemophilus influenzae (0%). Listeria monocytogenes and N. meningitidis are not routinely susceptibility tested.
Resistance is commonly detected, albeit still at relatively low levels for key drugs classes such as third-generation cephalosporins. This data demonstrates the need to consider predominant resistance phenotypes when choosing empiric therapies to treat CNS infections.
Central nervous system infections; meningitis; antibiotic susceptibility