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.
Document Type
Journal Article
Date of Publication
12-1-2023
Volume
11
Issue
6
PubMed ID
37815385
Publication Title
Microbiology Spectrum
Publisher
American Society for Microbiology
School
School of Medical and Health Sciences
RAS ID
64524
Funders
Australian Research Council
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