Document Type
Journal Article
Publisher
Public Library of Science
School
School of Medical and Health Sciences
RAS ID
25694
Abstract
Virulence of Clostridium difficile is primarily attributed to the large clostridial toxins A and B while the role of binary toxin (CDT) remains unclear. The prevalence of human strains of C. difficile possessing only CDT genes (A¯B¯CDT +) is generally low (< 5 %), however, this genotype is commonly found in neonatal livestock both in Australia and elsewhere. Zoonotic transmission of C. difficile has been suggested previously. Most human diagnostic tests will not detect A¯B¯CDT + strains of C. difficile because they focus on detection of toxin A and/or B. We performed a prospective investigation into the prevalence and genetic characteristics of A¯B¯CDT + C. difficile in symptomatic humans. All glutamate dehydrogenase or toxin B gene positive faecal specimens from symptomatic inpatients over 30 days (n = 43) were cultured by enrichment, and C. difficile PCR ribotypes (RTs) and toxin gene profiles determined. From 39 culture-positive specimens, 43 C. difficile isolates were recovered, including two A¯B¯CDT + isolates. This corresponded to an A¯B¯CDT + prevalence of 2/35 (5.7 %) isolates possessing at least one toxin, 2/10 (20 %) A¯B¯+ isolates, 2/3 CDT + isolates and 1/28 (3.6 %) presumed true CDI cases. No link to Australian livestock-associated C. difficile was found. Neither A¯B¯CDT + isolate was the predominant A¯B¯CDT + strain found in Australia, RT 033, nor did they belong to toxinotype XI. Previous reports infrequently describe A¯B¯CDT + C. difficile in patients and strain collections but the prevalence of human A¯B¯CDT + C. difficile is rarely investigated. This study highlights the occurrence of A−B−CDT+ strains of C. difficile in symptomatic patients, warranting further investigations of its role in human infection.
DOI
10.1371/journal.pone.0187658
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Comments
McGovern, A. M., Androga, G. O., Knight, D. R., Watson, M. W., Elliott, B., Foster, N. F., ... & Riley, T. V. (2017). Prevalence of binary toxin positive Clostridium difficile in diarrhoeal humans in the absence of epidemic ribotype 027. PloS one, 12(11), Article e0187658.
https://doi.org/10.1371/journal.pone.0187658