Clinicians should be aware of the increasing risk of C. difficile–associated disease and make efforts to control its transmission.
US hospital discharges for which Clostridium difficile–associated disease (CDAD) was listed as any diagnosis doubled from 82,000 (95% confidence interval [CI] 71,000–94,000) or 31/100,000 population in 1996 to 178,000 (95% CI 151,000–205,000) or 61/100,000 in 2003; this increase was significant between 2000 and 2003 (slope of linear trend 9.48; 95% CI 6.16–12.80, p = 0.01). The overall rate during this period was severalfold higher in persons >65 years of age (228/100,000) than in the age group with the next highest rate, 45–64 years (40/100,000; p<0.001). CDAD appears to be increasing rapidly in the United States and is disproportionately affecting older persons. Clinicians should be aware of the increasing risk for CDAD and make efforts to control transmission of C. difficile and prevent disease.
Clostridium difficile; national rates; hospital discharges; research
The dramatic changes in the epidemiology of Clostridium difficile infection (CDI) during recent years, with increases in incidence and severity of disease in several countries, have made CDI a global public health challenge. Increases in CDI incidence have been largely attributed to the emergence of a previously rare and more virulent strain, BI/NAP1/027. Increased toxin production and high-level resistance to fluoroquinolones have made this strain a very successful pathogen in healthcare settings. In addition, populations previously thought to be at low risk are now being identified as having severe CDI. Recent genetic analysis suggests that C. difficile has a highly fluid genome with multiple mechanisms to modify its content and functionality, which can make C. difficile adaptable to environmental changes and potentially lead to the emergence of more virulent strains. In the face of these changes in the epidemiology and microbiology of CDI, surveillance systems are necessary to monitor trends and inform public health actions.
Healthcare workers accounted for a large proportion of persons with severe acute respiratory syndrome (SARS) during the worldwide epidemic of early 2003. We conducted an investigation of healthcare workers exposed to laboratory-confirmed SARS patients in the United States to evaluate infection-control practices and possible SARS-associated coronavirus (SARS-CoV) transmission. We identified 110 healthcare workers with exposure within droplet range (i.e., 3 feet) to six SARS-CoV–positive patients. Forty-five healthcare workers had exposure without any mask use, 72 had exposure without eye protection, and 40 reported direct skin-to-skin contact. Potential droplet- and aerosol-generating procedures were infrequent: 5% of healthcare workers manipulated a patient’s airway, and 4% administered aerosolized medication. Despite numerous unprotected exposures, there was no serologic evidence of healthcare-related SARS-CoV transmission. Lack of transmission in the United States may be related to the relative absence of high-risk procedures or patients, factors that may place healthcare workers at higher risk for infection.
severe acute respiratory distress syndrome; healthcare workers; nosocomial; transmission
Clostridium difficile, the most commonly recognized diarrheagenic pathogen among hospitalized persons, can cause outpatient diarrhea. Of 1,091 outpatients with diarrhea, we found 43 (3.9%) who were positive for C. difficile toxin. Only 7 had no recognized risk factors, and 3 had neither risk factors nor co-infection with another enteric pathogen.
Clostridium difficile; diarrhea; outpatient; enteric; pathogen; bacteria; Maryland; Connecticut; United States; dispatch
Physicians need a better understanding of outcomes of these infections.
We evaluated the annual rate (cases/10,000 hospitalizations) of pediatric hospitalizations with Clostridium difficile infection (CDI; International Classification of Diseases, 9th revision, clinical modification code 008.45) in the United States. We performed a time-series analysis of data from the Kids’ Inpatient Database within the Health Care Cost and Utilization Project during 1997–2006 and a cross-sectional analysis within the National Hospital Discharge Survey during 2006. The rate of pediatric CDI-related hospitalizations increased from 7.24 to 12.80 from 1997 through 2006; the lowest rate was for children <1 year of age. Although incidence was lowest for newborns (0.5), incidence for children <1 year of age who were not newborns (32.01) was similar to that for children 5–9 years of age (35.27), which in turn was second only to incidence for children 1–4 years of age (44.87). Pediatric CDI-related hospitalizations are increasing. A better understanding of the epidemiology and outcomes of CDI is urgently needed.
Clostridium difficile; bacteria; pediatric; hospital; children; epidemiology; United States; research
Clostridium difficile isolates from presumed community-associated infections (n = 92) were characterized by toxinotyping, pulsed-field gel electrophoresis, tcdC and cdtB PCR, and antimicrobial susceptibility. Nine toxinotypes (TOX) and 31 PFGE patterns were identified. TOX 0 (48, 52%), TOX III (18, 20%), and TOX V (9, 10%) were the most common; three isolates were nontoxigenic.
Antimicrobial drug exposure is the most common modifiable risk factor for infection.
We determined estimated incidence of and risk factors for community-associated Clostridium difficile infection (CA-CDI) among patients treated at 6 North Carolina hospitals. CA-CDI case-patients were defined as adults (>18 years of age) with a positive stool test result for C. difficile toxin and no hospitalization within the prior 8 weeks. CA-CDI incidence was 21 and 46 per 100,000 person-years in Veterans Affairs (VA) outpatients and Durham County populations, respectively. VA case-patients were more likely than controls to have received antimicrobial drugs (adjusted odds ratio [aOR] 17.8, 95% confidence interval [CI] 6.6–48] and to have had a recent outpatient visit (aOR 5.1, 95% CI 1.5–17.9). County case-patients were more likely than controls to have received antimicrobial drugs (aOR 9.1, 95% CI 2.9–28.9), to have gastroesophageal reflux disease (aOR 11.2, 95% CI 1.9–64.2), and to have cardiac failure (aOR 3.8, 95% CI 1.1–13.7). Risk factors for CA-CDI overlap with those for healthcare-associated infection.
Clostridium difficile; enteric infections; incidence; risk factors; community; bacteria; research
To determine the presence of Clostridium difficile, we sampled cooked and uncooked meat products sold in Tucson, Arizona. Forty-two percent contained toxigenic C. difficile strains (either ribotype 078/toxinotype V [73%] or 027/toxinotype III [NAP1 or NAP1-related; 27%]). These findings indicate that food products may play a role in interspecies C. difficile transmission.
Clostridium difficile and associated disease; enteric diseases; retail meats; food animals; dispatch
We previously reported Clostridium difficile in 20% of retail meat in Canada, which raised concerns about potential foodborne transmissibility. Here, we studied the genetic diversity of C. difficile in retail meats, using a broad Canadian sampling infrastructure and 3 culture methods. We found 6.1% prevalence and indications of possible seasonality (highest prevalence in winter).
Enteric infections; bacteria; Clostridium difficile; foodborne; ribotypes; seasonality; hypervirulent; meat; Canada; dispatch
Five of the seven cases of vancomycin-resistant Staphylococcus aureus (VRSA) infection identified to date have occurred in southeastern Michigan. VRSA isolates from the four most recent cases (all from Michigan) were characterized. The vanA gene was localized to a single plasmid in each VRSA isolate. The pulsed-field gel electrophoresis patterns of chromosomal DNA and the restriction profile of the plasmid demonstrated that the four isolates were unique and differed from the first three VRSA isolates. Vancomycin-resistant Enterococcus (VRE) isolates, all of which were Enterococcus faecalis, were recovered from case patients 4 to 6. Each VRE isolate transferred vancomycin resistance to E. faecalis JH2-2 by conjugation. PCRs for vanA and the Inc18-like plasmid genes traA and repR confirmed the presence of an Inc18-like vanA plasmid in all VRE isolates and transconjugants. An Inc18-like vanA plasmid was identified in the VRSA isolate from case patient 7. These findings suggest a role of Inc18-like plasmids as vanA donors.
Such strains are uncommon causes of severe human disease but may be increasing in incidence.
Clostridium difficile is a recognized pathogen in neonatal pigs and may contribute to enteritis in calves. Toxinotype V strains have been rare causes of human C. difficile–associated disease (CDAD). We examined toxinotype V in human disease, the genetic relationship of animal and human toxinotype V strains, and in vitro toxin production of these strains. From 2001 through 2006, 8 (1.3%) of 620 patient isolates were identified as toxinotype V; before 2001, 7 (<0.02%) of ≈6,000 isolates were identified as toxinotype V. Six (46.2%) of 13 case-patients for whom information was available had community-associated CDAD. Molecular characterization showed a high degree of similarity between human and animal toxinotype V isolates; all contained a 39-bp tcdC deletion and most produced binary toxin. Further study is needed to understand the epidemiology of CDAD caused by toxinotype V C. difficile, including the potential of foodborne transmission to humans.
Clostridium difficile; interspecies transmission; molecular epidemiology; research
CDAD led to significantly worse outcomes in these patients.
Data are limited on the attributable outcomes of Clostridium difficile–associated disease (CDAD), particularly in CDAD-endemic settings. We conducted a retrospective cohort study of nonsurgical inpatients admitted for >48 hours in 2003 (N = 18,050). The adjusted hazard ratios for readmission (hazard ratio 2.19, 95% confidence interval [CI] 1.87–2.55) and deaths within 180 days (hazard ratio 1.23, 95% CI 1.03–1.46) were significantly different among CDAD case-patients and noncase patients. In a propensity score matched-pairs analysis that used a nested subset of the cohort (N = 706), attributable length of stay attributable to CDAD was 2.8 days, attributable readmission at 180 days was 19.3%, and attributable death at 180 days was 5.7%. CDAD patients were significantly more likely than controls to be discharged to a long-term-care facility or outside hospital. Even in a nonoutbreak setting, CDAD had a statistically significant negative impact on patient illness and death, and the impact of CDAD persisted beyond hospital discharge.
Clostridium difficile; attributable mortality; outcomes; healthcare epidemiology; hospital-associated infections; research
In recent years, the incidence and severity of Clostridium difficile-associated disease (CDAD) have increased dramatically. Beginning in 2000, widespread regional outbreaks associated with a previously uncommon hypervirulent strain of C. difficile have occurred in North America and Europe. Most likely because of increased toxin production as well as other virulence factors, this epidemic strain has caused more severe and refractory disease leading to complications, including intensive care unit admission, colectomies, and death. Worldwide increasing use of fluoroquinolones and cephalosporins has likely contributed to the proliferation of this epidemic strain, which is highly resistant to both. The elderly have been disproportionately affected by CDAD, but C. difficile has also recently emerged in populations previously considered to be at low risk, including healthy outpatients and peripartum women, although it is unknown if these cases are related to the epidemic strain. Nevertheless, transmission within hospitals is the major source of C. difficile acquisition, and previous or concurrent antimicrobial use is almost universal among cases. Applying current evidence-based strategies for management and prevention is critically important, and clinicians should maintain an awareness of the changing epidemiology of CDAD and take measures to reduce the risk of disease in patients.
The rise in visits to outpatient and emergency departments for skin and soft tissue infections may reflect the emergence of community-associated methicillin-resistant Staphylococcus aureus.
To describe the number and treatment of skin and soft tissue infections likely caused by Staphylococcus aureus in the United States, we analyzed data from the 1992–1994 and 2001–2003 National Ambulatory Medical Care Surveys and National Hospital Ambulatory Medical Care Surveys. Each year, data were reported by an average of 1,400 physicians, 230 outpatient departments, and 390 emergency departments for 30,000, 33,000, and 34,000 visits, respectively. During 2001–2003, the number of annual ambulatory care visits for skin and soft tissue infections was 11.6 million; the visit rate was 410.7 per 10,000 persons. During the study period, rates of overall and physician office visits did not differ; however, rates of visits to outpatient and emergency departments increased by 59% and 31%, respectively. This increase may reflect the emergence of community-acquired methicillin-resistant S. aureus infections.
Skin and soft tissue infections; Staphylococcus aureus; ambulatory care; research
We conducted a retrospective cohort study to compare Clostridium difficile–associated disease rates determined by C. difficile–toxin assays and International Classification of Diseases, 9th Revision (ICD-9) codes. The correlation between toxin assay results and ICD-9 codes was good (κ = 0.72, p<0.01). The sensitivity of the ICD-9 codes was 78% and the specificity was 99.7%.
Clostridium difficile; International Classification of Diseases; hospital infections; dispatch
To understand the Candida colonization of human immunodeficiency virus (HIV)-infected outpatients in Taiwan, we have conducted a prospective cohort study of Candida colonization and its risk factors at the National Taiwan University Hospital from 1999 to 2002. More than 50% of the patients were colonized with Candida species, and 12% developed symptomatic candidiasis. Patients colonized with fluconazole-resistant strains of Candida species had a higher prevalence of candidiasis than those colonized with susceptible strains. Our analysis found that antibiotic treatment and lower CD4+ counts (<200 cells/mm3) increased the rate of oropharyngeal candidiasis in HIV-infected patients, while antiretroviral therapy protected patients from the development of candidiasis.
Late recognition of severe acute respiratory syndrome (SARS) was associated with no known SARS contact, hospitalization before the nosocomial outbreak was recognized, symptom onset while hospitalized, wards with SARS clusters, and postoperative status. SARS is difficult to recognize in hospitalized patients with a variety of underlying conditions in the absence of epidemiologic links.
SARS; nosocomial infections; surveillance; dispatch
The healthcare setting was important in the early spread of severe acute respiratory syndrome (SARS) in both Toronto and Taiwan. Healthcare workers, patients, and visitors were at increased risk for infection. Nonetheless, the ability of individual SARS patients to transmit disease was quite variable. Unrecognized SARS case-patients were a primary source of transmission and early detection and intervention were important to limit spread. Strict adherence to infection control precautions was essential in containing outbreaks. In addition, grouping patients into cohorts and limiting access to SARS patients minimized exposure opportunities. Given the difficulty in implementing several of these measures, controls were frequently adapted to the acuity of SARS care and level of transmission within facilities. Although these conclusions are based only on a retrospective analysis of events, applying the experiences of Toronto and Taiwan to SARS preparedness planning efforts will likely minimize future transmission within healthcare facilities.
severe acute respiratory syndrome; infection control; delivery of healthcare
We report a laboratory-confirmed case of severe acute respiratory syndrome (SARS) in a pregnant woman. Although the patient had respiratory failure, a healthy infant was subsequently delivered, and the mother is now well. There was no evidence of viral shedding at delivery. Antibodies to SARS virus were detected in cord blood and breast milk.
severe acute respiratory syndrome; SARS; pregnancy; coronavirus; pneumonia; virus shedding; placenta previa; gestational diabetes; breast milk; breast feeding
Infection of healthcare workers with the severe acute respiratory syndrome–associated coronavirus (SARS-CoV) is thought to occur primarily by either contact or large respiratory droplet transmission. However, infrequent healthcare worker infections occurred despite the use of contact and droplet precautions, particularly during certain aerosol-generating medical procedures. We investigated a possible cluster of SARS-CoV infections in healthcare workers who used contact and droplet precautions during attempted cardiopulmonary resuscitation of a SARS patient. Unlike previously reported instances of transmission during aerosol-generating procedures, the index case-patient was unresponsive, and the intubation procedure was performed quickly and without difficulty. However, before intubation, the patient was ventilated with a bag-valve-mask that may have contributed to aerosolization of SARS-CoV. On the basis of the results of this investigation and previous reports of SARS transmission during aerosol-generating procedures, a systematic approach to the problem is outlined, including the use of the following: 1) administrative controls, 2) environmental engineering controls, 3) personal protective equipment, and 4) quality control.
SARS virus; resuscitation; occupational health; infection control; transmission; healthcare worker
Streptococcus pneumoniae is a rarely recognized cause of neonatal sepsis. We present a recent case of S. pneumoniae bacteremia acquired on the first day of life in a neonate born at 30 weeks of gestation to a mother without prenatal care who had prolonged rupture of the membranes and received intravenous ampicillin prior to delivery. The isolate was resistant to penicillin, with a MIC of the drug of 4 μg/ml. The child responded to a 7-day course of intravenous vancomycin. S. pneumoniae was recovered from the vagina of the mother on a swab culture collected prior to delivery, and isolates from mother and child were confirmed to be identical on the basis of pulsed-field gel electrophoresis. Although neonatal sepsis due to the peripartum transmission of S. pneumoniae is rare, this case highlights the concern that increasing efforts to prevent group B streptococcus neonatal disease may lead to an increase in neonatal infections due to resistant organisms.
Vancomycin resistant enterococci (VRE) with VanB phenotype-vanA genotype incongruence were found in all 39 VRE isolated from chicken carcasses and four human VRE isolates in Taiwan. Three identical mutations in the vanS gene were found in the VanB phenotype-vanA genotype VRE sequenced. This finding indicates possible transmission of glycopeptide resistance among different hosts.
A survey of 1,203 Escherichia coli isolates from 44 hospitals in Taiwan revealed that 136 (11.3%) isolates were resistant to fluoroquinolones and that another 261 (21.7%) isolates had reduced susceptibility. Resistance was more common in isolates responsible for hospital-acquired (mostly in intensive care units) infections (17.5%) than in other adult inpatient (11.4%; P = 0.08) and outpatient isolates (11.9%; P > 0.1). Similarly, reduced susceptibility was more common in isolates responsible for hospital-acquired infections (30.9%) than in other adult inpatient (21.0%; P = 0.04) and outpatient (21.4%; P = 0.06) isolates. Isolates from pediatric patients were less likely to be resistant (1.3 versus 12.0%; P < 0.01) but were nearly as likely to have reduced susceptibility (17.7 versus 21.9%; P > 0.1) as nonpediatric isolates. There was an inverse relationship in the proportion of isolates that were resistant versus the proportion that had reduced susceptibility among isolates from individual hospitals (R = 0.031; P < 0.05). In an analysis of isolates from two hospitals, all 9 resistant strains possessed double point mutations in gyrA and all 19 strains with reduced susceptibility strains had single point mutations; no mutations were found among fully susceptible strains. Risk factors for resistance included underlying cancer (odds ratio [OR], 83; 95% confidence interval [CI95], 7.3 to 2,241; P < 0.001), exposure to a quinolone (OR, undefined; P = 0.02), and exposure to a nonquinolone antibiotic (OR, 20; CI95, 2.2 to 482; P < 0.001); underlying cancer was the only independent risk factor (OR, 83; CI95, 8.6 to 807; P < 0.001). There were no significant associations between any of these factors and reduced susceptibility. Whereas acute and chronic quinolone use in cancer patients is a major selective pressure for resistance, other undetermined but distinct selective pressures appear to be more responsible for reduced susceptibility to fluoroquinolones in E. coli.
Yeasts are an increasingly common cause of nosocomial bloodstream infections. Methods for their detection are many; controlled comparisons are few. The vented FAN aerobic blood culture medium has been shown to be superior to the standard BacT/ALERT aerobic medium for the detection of fungemia as well as bacteremia. The BACTEC selective fungal medium (FM) (BD Biosciences, Sparks, Md.) allowed detection of more episodes of fungemia than did a resin-containing medium with equal volumes of blood cultured. Therefore, we compared vented FAN to FM for the ability to recover fungi from the blood of patients who were at increased risk of having fungemia. From 5,109 cultures processed for which both FAN and FM bottles were adequately filled, fungi were recovered from 87 cultures. Of these, 47 were detected with both bottles, 12 were detected with FAN only, and 28 were detected with FM only (P < 0.05). FAN was the first bottle positive for 36 of the 47 cultures for which both bottles yielded the same fungus, whereas the FM bottle was the first bottle positive for 11 cultures (P < 0.001). A total of 54 episodes of fungemia were identified, with 40 detected by both media, 4 detected only by FAN, and 10 detected only by FM (P value, not significant). We conclude that the vented FAN aerobic bottle is comparable to the FM bottle for detection of episodes of yeast infection but has the added benefit of detecting bacteria.