Evolutionary and genomic insights into Clostridioides difficile sequence type 11: A diverse zoonotic and antimicrobial-resistant lineage of global One Health importance

Clostridioides difficile (Clostridium difficile) sequence type 11 (ST11) is well established in production animal populations worldwide and contributes considerably to the global burden of C. difficile infection (CDI) in humans. Increasing evidence of shared ancestry and genetic overlap of PCR ribotype 078 (RT078), the most common ST11 sublineage, between human and animal populations suggests that CDI may be a zoonosis. We performed whole-genome sequencing (WGS) on a collection of 207 ST11 and closely related ST258 isolates of human and veterinary/environmental origin, comprising 16 RTs collected from Australia, Asia, Europe, and North America. Core genome single nucleotide variant (SNV) analysis identified multiple intraspecies and interspecies clonal groups (isolates separated by ≤2 core genome SNVs) in all the major RT sublineages: 078, 126, 127, 033, and 288. Clonal groups comprised isolates spread across different states, countries, and continents, indicative of reciprocal long-range dissemination and possible zoonotic/anthroponotic transmission. Antimicrobial resistance genotypes and phenotypes varied across host species, geographic regions, and RTs and included macrolide/lincosamide resistance (Tn6194 [ermB]), tetracycline resistance (Tn6190 [tetM] and Tn6164 [tet44]), and fluoroquinolone resistance (gyrA/B mutations), as well as numerous aminoglycoside resistance cassettes. The population was defined by a large “open” pan-genome (10,378 genes), a remarkably small core genome of 2,058 genes (only 19.8% of the gene pool), and an accessory genome containing a large and diverse collection of important prophages of the Siphoviridae and Myoviridae. This study provides novel insights into strain relatedness and genetic variability of C. difficile ST11, a lineage of global One Health importance. IMPORTANCE: Historically, Clostridioides difficile (Clostridium difficile) has been associated with life-threatening diarrhea in hospitalized patients. Increasing rates of C. difficile infection (CDI) in the community suggest exposure to C. difficile reservoirs outside the hospital, including animals, the environment, or food. C. difficile sequence type 11 (ST11) is known to infect/colonize livestock worldwide and comprises multiple ribotypes, many of which cause disease in humans, suggesting CDI may be a zoonosis. Using high-resolution genomics, we investigated the evolution and zoonotic potential of ST11 and a new closely related ST258 lineage sourced from diverse origins. We found multiple intra- and interspecies clonal transmission events in all ribotype sublineages. Clones were spread across multiple continents, often without any health care association, indicative of zoonotic/anthroponotic long-range dissemination in the community. ST11 possesses a massive pan-genome and numerous clinically important antimicrobial resistance elements and prophages, which likely contribute to the success of this globally disseminated lineage of One Health importance

Clostridium difficile contamination of health care workers' hands and its potential contribution to the spread of infection: Review of the literature

International audienc

Clostridium difficile contamination of health care workers' hands and its potential contribution to the spread of infection: Review of the literature

International audienc

Sequence similarity of Clostridium difficile strains by analysis of conserved genes and genome content is reflected by their ribotype affiliation.

International audiencePCR-ribotyping is a broadly used method for the classification of isolates of Clostridium difficile, an emerging intestinal pathogen, causing infections with increased disease severity and incidence in several European and North American countries. We have now carried out clustering analysis with selected genes of numerous C. difficile strains as well as gene content comparisons of their genomes in order to broaden our view of the relatedness of strains assigned to different ribotypes. We analyzed the genomic content of 48 C. difficile strains representing 21 different ribotypes. The calculation of distance matrix-based dendrograms using the neighbor joining method for 14 conserved genes (standard phylogenetic marker genes) from the genomes of the C. difficile strains demonstrated that the genes from strains with the same ribotype generally clustered together. Further, certain ribotypes always clustered together and formed ribotype groups, i.e. ribotypes 078, 033 and 126, as well as ribotypes 002 and 017, indicating their relatedness. Comparisons of the gene contents of the genomes of ribotypes that clustered according to the conserved gene analysis revealed that the number of common genes of the ribotypes belonging to each of these three ribotype groups were very similar for the 078/033/126 group (at most 69 specific genes between the different strains with the same ribotype) but less similar for the 002/017 group (86 genes difference). It appears that the ribotype is indicative not only of a specific pattern of the amplified 16S-23S rRNA intergenic spacer but also reflects specific differences in the nucleotide sequences of the conserved genes studied here. It can be anticipated that the sequence deviations of more genes of C. difficile strains are correlated with their PCR-ribotype. In conclusion, the results of this study corroborate and extend the concept of clonal C. difficile lineages, which correlate with ribotypes affiliation

: Anaerobe

International audienceINTRODUCTION: The magnitude and scope of Clostridioides difficile infection (CDI) has changed with an increase in incidence and severity. The epidemiology of CDI is not well known in France due to difficulties to conduct large continuous surveillance. The objectives were to compare the characteristics of patients with CDI collected through repeated point prevalence survey via DIFTEC™, a free electronic tool, with those from previous French or European studies. METHODS: DIFTEC™ was developed to evaluate epidemiological burden, diagnostic strategies and management of CDI in France. National and European guidelines were used for definitions. A literature review of studies conducted in Western Europe on CDI and published between January, 2008 and May, 2018 was done to compare their data with those included in the DIFTEC™ database. RESULTS: From January 2016, to December 2017, 455 CDI episodes from 22 French hospitals were included. Most of CDI cases were health-care associated (HCA) (78%). The comparison between included patients and French literature data showed that the rates of previous antibiotics exposure, crude mortality and recurrence were not statistically different. However HCA-CDI was significantly more frequent in the DIFTEC™ study. Gender distribution, recurrence and crude mortality rates were not statistically different compared to European data. HCA-CDI was more frequent in the DIFTEC™ study whereas previous treatment with proton pump inhibitors and antibiotics were significantly higher in European studies. DISCUSSION: These results illustrated the added value of a new tool for increasing the reliable knowledge of CDI in France based on epidemiological surveillance implemented in health-care settings

Anaerobe

INTRODUCTION: The magnitude and scope of Clostridioides difficile infection (CDI) has changed with an increase in incidence and severity. The epidemiology of CDI is not well known in France due to difficulties to conduct large continuous surveillance. The objectives were to compare the characteristics of patients with CDI collected through repeated point prevalence survey via DIFTEC™, a free electronic tool, with those from previous French or European studies. METHODS: DIFTEC™ was developed to evaluate epidemiological burden, diagnostic strategies and management of CDI in France. National and European guidelines were used for definitions. A literature review of studies conducted in Western Europe on CDI and published between January, 2008 and May, 2018 was done to compare their data with those included in the DIFTEC™ database. RESULTS: From January 2016, to December 2017, 455 CDI episodes from 22 French hospitals were included. Most of CDI cases were health-care associated (HCA) (78%). The comparison between included patients and French literature data showed that the rates of previous antibiotics exposure, crude mortality and recurrence were not statistically different. However HCA-CDI was significantly more frequent in the DIFTEC™ study. Gender distribution, recurrence and crude mortality rates were not statistically different compared to European data. HCA-CDI was more frequent in the DIFTEC™ study whereas previous treatment with proton pump inhibitors and antibiotics were significantly higher in European studies. DISCUSSION: These results illustrated the added value of a new tool for increasing the reliable knowledge of CDI in France based on epidemiological surveillance implemented in health-care settings

: Anaerobe

International audienceINTRODUCTION: The magnitude and scope of Clostridioides difficile infection (CDI) has changed with an increase in incidence and severity. The epidemiology of CDI is not well known in France due to difficulties to conduct large continuous surveillance. The objectives were to compare the characteristics of patients with CDI collected through repeated point prevalence survey via DIFTEC™, a free electronic tool, with those from previous French or European studies. METHODS: DIFTEC™ was developed to evaluate epidemiological burden, diagnostic strategies and management of CDI in France. National and European guidelines were used for definitions. A literature review of studies conducted in Western Europe on CDI and published between January, 2008 and May, 2018 was done to compare their data with those included in the DIFTEC™ database. RESULTS: From January 2016, to December 2017, 455 CDI episodes from 22 French hospitals were included. Most of CDI cases were health-care associated (HCA) (78%). The comparison between included patients and French literature data showed that the rates of previous antibiotics exposure, crude mortality and recurrence were not statistically different. However HCA-CDI was significantly more frequent in the DIFTEC™ study. Gender distribution, recurrence and crude mortality rates were not statistically different compared to European data. HCA-CDI was more frequent in the DIFTEC™ study whereas previous treatment with proton pump inhibitors and antibiotics were significantly higher in European studies. DISCUSSION: These results illustrated the added value of a new tool for increasing the reliable knowledge of CDI in France based on epidemiological surveillance implemented in health-care settings

Core-, pan- and accessory genome analyses of Clostridium neonatale: insights into genetic diversity

International audienceClostridium neonatale is a potential opportunistic pathogen recovered from faecal samples in cases of necrotizing enterocolitis (NEC), a gastrointestinal disease affecting preterm neonates. Although the C. neonatale species description and name validation were published in 2018, comparative genomics are lacking. In the present study, we provide the closed genome assembly of the C. neonatale ATCC BAA-265 T (=250.09) reference strain with a manually curated functional annotation of the coding sequences. Pan-, core- and accessory genome analyses were performed using the complete 250.09 genome (4.7 Mb), three new assemblies (4.6–5.6 Mb), and five publicly available draft genome assemblies (4.6–4.7 Mb). The C. neonatale pan-genome contains 6840 genes, while the core-genome has 3387 genes. Pan-genome analysis revealed an ‘open’ state and genomic diversity. The strain-specific gene families ranged from five to 742 genes. Multiple mobile genetic elements were predicted, including a total of 201 genomic islands, 13 insertion sequence families, one CRISPR-Cas type I-B system and 15 predicted intact prophage signatures. Primary virulence classes including offensive, defensive, regulation of virulence-associated genes and non-specific virulence factors were identified. The presence of a tet (W/N/W) gene encoding a tetracycline resistance ribosomal protection protein and a 23S rRNA methyltransferase ermQ gene were identified in two different strains. Together, our results revealed a genetic diversity and plasticity of C. neonatale genomes and provide a comprehensive view of this species genomic features, paving the way for the characterization of its biological capabilities