Prevalence and Duration of Asymptomatic Clostridium difficile Carriage among Healthy Subjects in Pittsburgh, Pennsylvania

Abstract

bPrevious studies suggested that 7 to 15% of healthy adults are colonized with toxigenic Clostridium difficile. To investigate the epidemiology, genetic diversity, and duration of C. difficile colonization in asymptomatic persons, we recruited healthy adults from the general population in Allegheny County, Pennsylvania. Participants provided epidemiological and dietary intake data and submitted stool specimens. The presence of C. difficile in stool specimens was determined by anaerobic culture. Stool specimens yielding C. difficile underwent nucleic acid testing of the tcdA gene segment with a commercial assay; tcdC genotyping was performed on C. difficile isolates. Subjects positive for C. difficile by toxigenic anaerobic culture were asked to submit additional specimens. One hundred six (81%) of 130 subjects submitted specimens, and 7 (6.6%) of those subjects were colonized with C. difficile. Seven distinct tcdC genotypes were observed among the 7 C. difficile-colonized individuals, including tcdC genotype 20, which has been found in uncooked ground pork in this region. Two (33%) out of 6 C. difficile-colonized subjects who submitted additional specimens tested positive for identical C. difficile strains on successive occasions, 1 month apart. The prevalence of C. difficile carriage in this healthy cohort is concordant with prior estimates. C. difficile-colonized individuals may be important reservoirs for C. difficile and may falsely test positive for infections due to C. difficile when evaluated for community-acquired diarrhea caused by other enteric pathogens.C lostridium difficile infections (CDIs) have shown dramatic increases in incidence and morbidity during the past decade (1). While C. difficile is well established as a health careassociated pathogen, incidence estimates for community-acquired CDIs vary between 6 and 30% (2-4). The source of C. difficile in community-acquired cases is unclear. Prevalence estimates for asymptomatic C. difficile colonization range from 7 to 15% among healthy, non-health care workers outside the United States to 1 to 4% among health care workers in the United States and abroad (5-9). Individuals colonized with C. difficile could represent a potential reservoir of strains imported into hospitals, as well as a source of false-positive clinical test results for CDIs among patients with community-acquired diarrheal illness, especially norovirus and Clostridium perfringens. We studied the prevalence, genotypic distribution, and duration of C. difficile carriage among healthy adults in Allegheny County, Pennsylvania, and evaluated potential risk factors for asymptomatic colonization. We also examined the relative abundance of C. difficile and the sensitivity of a commercial nucleic acid test for detection of C. difficile in the stool of healthy colonized individuals. MATERIALS AND METHODSHealthy adult residents (Ն18 years of age) in Allegheny County, Pennsylvania, were recruited for participation via print and electronic advertisements in September 2012 through April 2013. Ind...

Detection of Clostridium difficile in Feces of Asymptomatic Patients Admitted to the Hospital

“…Furthermore, only one of 24 C. difficile strains belonged to the epidemic ribotype 078, and no 027 strains were detected. Other studies confirm this finding (31)(32)(33), supporting the hypothesis that epidemic strains seldom lead to asymptomatic colonization.…”

Environmental Contamination in Households of Patients with Recurrent Clostridium difficile Infection

“…Reported carriage prevalence rates vary by group, e.g., 6 to 13% for healthy adults, 20 to 30% for recently hospitalized patients, and 51% for long-term-care facility residents during a CDI outbreak, consistent with increased carriage as a result of exposure to environmental contamination and increased exposure to antimicrobials in hospitals and long-term-care facilities (8)(9)(10)(11). Up to 70% of healthy newborns and infants are also colonized with C. difficile (12).…”

Contamination of the Hospital Environment From Potential Clostridium difficile Excretors Without Active Infection

“…Although the prevalence of asymptomatic colonization has been described in several studies, with rates ranging 6.6%-15%, [3][4][5] the prevalence of excretors is less well described. Guerrero and colleagues 6 sampled the skin and environment of patients who tested positive by PCR.…”