Document Type
Journal Article
Publication Title
Microbiology Spectrum
Volume
11
Issue
6
PubMed ID
37815385
Publisher
American Society for Microbiology
School
School of Medical and Health Sciences
RAS ID
64524
Funders
Australian Research Council
Abstract
There has been a decrease in healthcare-associated Clostridioides difficile infection (CDI) in Australia, coupled with an increase in the genetic diversity of strains isolated in these settings, and an increase in community-associated cases. To explore this changing epidemiology, we studied the genetic relatedness of C. difficile isolated from patients at a major hospital in Melbourne, Australia. Whole-genome sequencing of C. difficile isolates from symptomatic (n = 61) and asymptomatic (n = 10) hospital patients was performed. Genomic comparisons were made using single-nucleotide polymorphism (SNP) analysis, ribotyping, and toxin, resistome, and mobilome profiling. C. difficle clade 1 strains were found to be predominant (64/71), with most strains (63/71) encoding both toxins A and B (A+B+). Despite these similarities, only two isolates were genetically related ( ≤ 2 SNPs) and a diverse range of ribotypes was detected, with those predominating including ribotypes commonly found in community-associated cases. Five non-toxigenic (A−B−CDT−) clade 1 strains were identified, all in asymptomatic patients. Three clade 4 (A−B+CDT−) and four clade 5 (A+B+CDT+) strains were detected also, with these strains more likely to carry antimicrobial resistance determinants, many of which were associated with mobile genetic elements. Overall, within a single hospital, C. difficile-associated disease was caused by a diverse range of strains, including many strain types associated with community and environmental sources. While strains carried asymptomatically were more likely to be non-toxigenic, toxigenic strains were isolated also from asymptomatic patients, which together suggest the presence of diverse sources of transmission, potentially including asymptomatic patients.
DOI
10.1128/spectrum.01352-23
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Comments
Larcombe, S., Williams, G. C., Amy, J., Lim, S. C., Riley, T. V., Muleta, A., . . . Lyras, D. (2023). A genomic survey of clostridioides difficile isolates from hospitalized patients in Melbourne, Australia. Microbiology Spectrum, 11(6), 1-14. https://doi.org/10.1128/spectrum.01352-23