Peptoclostridium Difficile Research Articles

Prevalence of Detection of Clostridioides difficile Among Asymptomatic Children

Detection of Clostridioides difficile has frequently been described in asymptomatic infants and children, but accurate estimates across the age spectrum are unavailable. To assess the prevalence of C difficile detection among asymptomatic children across the age spectrum. This systematic review and meta-analysis included a search of the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, Scopus, and Web of Science for articles published from January 1, 1990, to December 31, 2020. Search terms included Clostridium difficile, Peptoclostridium difficile, Clostridioides difficile, CDF OR CDI OR c diff OR c difficile, Clostridium infections OR cd positive diarrhea OR cd positive diarrhea OR Clostridium difficile OR Peptoclostridium difficile OR pseudomembranous colitis OR pseudomembranous enterocolitis, enterocolitis, and pseudomembranous. These were combined with the following terms: bacterial colonization and colonization OR colonized OR colonizing OR epidemiology OR prevalence OR seroprevalence. Studies were screened independently by 2 authors. Studies were included if they reported testing for C difficile among asymptomatic children (ie, children without diarrhea) younger than 18 years. Data were extracted independently and in duplicate by 2 reviewers. Preferred Reporting Items for a Systematic Review and Meta-analysis (PRISMA) guidelines were used. Data were pooled using a random-effects model. The primary outcome was prevalence of C difficile detection among asymptomatic children. Secondary outcomes included prevalence of toxigenic vs nontoxigenic strains of C difficile and prevalence of C difficile detection stratified by geographic region, income status, testing method, and year of testing. A total of 95 studies with 19 186 participants were included. Rates of detection of toxigenic or nontoxigenic C difficile were greatest among infants aged 6 to 12 months (41%; 95% CI, 32%-50%) and decreased to 12% (95% CI, 7%-18%) among children aged 5 to 18 years. The prevalence of toxigenic C difficile colonization was lower, peaking at 14% (95% CI, 8%-21%) among infants aged 6 to 12 months and decreasing to 6% (95% CI, 2%-11%) among children older than 5 years. Although prevalence differed by geographic region (ie, North and South America vs Europe: β, -0.151, P = .001; North and South America vs Western Pacific: β, 0.136, P = .007), there was no difference by testing method (ie, culture vs polymerase chain reaction: β, 0.069, P = .052; culture vs enzyme immunoassay: β, -0.178, P = .051), income class (low-middle income vs high income: β, -0.144, P = .23; upper-middle vs high income: β, -0.020, P = .64), or period (before 1990 vs 2010-2020: β, -0.125, P = .19; 1990-1999 vs 2010-2020: β, -0.037, P = .42; 2000-2009 vs 2010-2020: β, -0.006, P = .86). In this systematic review and meta-analysis, C difficile colonization rates among children were greatest at 6 to 12 months of age and decreased thereafter. These estimates may provide context for interpreting C difficile test results among young children.

Changes in the gut microbiota during and after commercial helium–oxygen saturation diving in China

ObjectivesThe influence of commercial helium–oxygen saturation diving on divers’ gut microbiotas was assessed to provide dietary suggestion.MethodsFaecal samples of 47 divers working offshore were collected before (T1), during (T2) and...

"One-Pot" Sample Processing Method for Proteome-Wide Analysis of Microbial Cells and Spores.

PurposeBacterial endospores, the transmissible forms of pathogenic bacilli and clostridia, are heterogeneous multilayered structures composed of proteins. These proteins protect the spores against a variety of stresses, thus helping spore survival, and assist in germination, by interacting with the environment to form vegetative cells. Owing to the complexity, insolubility, and dynamic nature of spore proteins, it has been difficult to obtain their comprehensive protein profiles.Experimental designThe intact spores of Bacillus subtilis, Bacillus cereus, and Peptoclostridium difficile and their vegetative counterparts were disrupted by bead beating in 6 m urea under reductive conditions. The heterogeneous mixture was then double digested with LysC and trypsin. Next, the peptide mixture was pre‐fractionated with zwitterionic hydrophilic interaction liquid chromatography (ZIC‐HILIC) followed by reverse‐phase LC‐FT‐MS analysis of the fractions.Results"One‐pot" method is a simple, robust method that yields identification of >1000 proteins with high confidence, across all spore layers from B. subtilis, B. cereus, and P. difficile.Conclusions and medical relevanceThis method can be employed for proteome‐wide analysis of non‐spore‐forming as well as spore‐forming pathogens. Analysis of spore protein profile will help to understand the sporulation and germination processes and to distinguish immunogenic protein markers.

PWE-094 Understanding The Efficacy of Faecal Microbiota Transplantation in Clostridium Difficile Infection: Re-Establishment of Gut Microbiota with The Ability to Degrade Bile?

Introduction Faecal microbiota transplantation (FMT) has recently emerged as a highly-effective therapy for recurrent/ refractory Clostridium difficile (recently re-named Peptoclostridium difficile) infection (CDI); however, the specific mechanisms underlying the efficacy of FMT remain largely unclear. Given that different bile salt metabolites differentially affect C. difficile ’s ability to germinate and grow both in vitro and in vivo, we hypothesised that CDI is characterised by perturbed bile acid metabolism, and that FMT may exert its efficacy through re-establishment of gut microbiota that restore this process to normal. Methods Stool samples were collected from healthy volunteer donors participating in an FMT programme, whilst serial stool samples were collected from a patient successfully treated with FMT for refractory CDI both pre- and post-transplantation. Samples were assayed for structure of the gut microbiota using 16 S rRNA gene sequencing, and for bile acid profiling via liquid chromatography mass spectrometry (LC-MS). Presence of bile salt hydrolases (responsible for deconjugation of glycine- and taurine-conjugated primary bile acids within the gut) was assessed via PCR of bacterial DNA extracted from stool. Results A 61 year-old man with refractory CDI was treated with FMT. He demonstrated a modest improvement in diarrhoea after a first FMT, but an immediate, complete and sustained resolution of symptoms after a second FMT from a different donor (performed two weeks after the first). 16 S rRNA gene sequencing demonstrated a pattern of faecal bacterial communities that closely resembled that of the healthy donors by one week after the second FMT. Faecal LC-MS analysis revealed the patient’s gut bile acid profile pre-FMT to be enriched sixfold in taurocholic acid (a potent trigger for C. difficile spore germination in vitro ). Post-FMT, the patient’s gut bile acid profile resembled that of healthy donors, with loss of taurocholate and enrichment of secondary bile acids (which are recognised in vitro as inhibitors of C. difficile growth). PCR of bacterial DNA extracted from faeces displayed no detectable BSH genes in the recipient either pre-FMT or by one week following the first FMT, but BSH presence was confirmed in the recipient by one week following the second FMT, as well as in both donors. Conclusion FMT may restore bile-degrading members of the gut microbiota, and consequently restore a normal bile acid metabolism to the gut that protects against C. difficile germination. Disclosure of Interest None Declared

The Clostridium difficile Dlt Pathway Is Controlled by the Extracytoplasmic Function Sigma Factor σV in Response to Lysozyme.

Clostridium difficile (also known as Peptoclostridium difficile) is a major nosocomial pathogen and a leading cause of antibiotic-associated diarrhea throughout the world. Colonization of the intestinal tract is necessary for C. difficile to cause disease. Host-produced antimicrobial proteins (AMPs), such as lysozyme, are present in the intestinal tract and can deter colonization by many bacterial pathogens, and yet C. difficile is able to survive in the colon in the presence of these AMPs. Our prior studies established that the Dlt pathway, which increases the surface charge of the bacterium by addition of d-alanine to teichoic acids, is important for C. difficile resistance to a variety of AMPs. We sought to determine what genetic mechanisms regulate expression of the Dlt pathway. In this study, we show that a dlt null mutant is severely attenuated for growth in lysozyme and that expression of the dltDABC operon is induced in response to lysozyme. Moreover, we found that a mutant lacking the extracytoplasmic function (ECF) sigma factor σ(V) does not induce dlt expression in response to lysozyme, indicating that σ(V) is required for regulation of lysozyme-dependent d-alanylation of the cell wall. Using reporter gene fusions and 5' RACE (rapid amplification of cDNA ends) analysis, we identified promoter elements necessary for lysozyme-dependent and lysozyme-independent dlt expression. In addition, we observed that both a sigV mutant and a dlt mutant are more virulent in a hamster model of infection. These findings demonstrate that cell wall d-alanylation in C. difficile is induced by lysozyme in a σ(V)-dependent manner and that this pathway impacts virulence in vivo.

Genome Sequence and Analysis of Peptoclostridium difficile Strain ZJCDC-S82.

Peptoclostridium difficile (Clostridium difficile) is the major pathogen associated with infectious diarrhea in humans. Concomitant with the increased incidence of C. difficile infection worldwide, there is an increasing concern regarding this infection type. This study reports a draft assembly and detailed sequence analysis of C. difficile strain ZJCDC-S82. The de novo assembled genome was 4.19 Mb in size, which includes 4,013 protein-coding genes, 41 rRNA genes, and 84 tRNA genes. Along with the nuclear genome, we also assembled sequencing information for a single plasmid consisting of 11,930 nucleotides. Comparative genomic analysis of C. difficile ZJCDC-S82 and two other previously published strains, such as M120 and CD630, showed extensive similarity. Phylogenetic analysis revealed that genetic diversity among C. difficile strains was not influenced by geographic location. Evolutionary analysis suggested that four genes encoding surface proteins exhibited positive selection in C. difficile ZJCDC-S82. Codon usage analysis indicated that C. difficile ZJCDC-S82 had high codon usage bias toward A/U-ended codons. Furthermore, codon usage patterns in C. difficile ZJCDC-S82 were predominantly affected by mutation pressure. Our results provide detailed information pertaining to the C. difficile genome associated with a strain from mainland China. This analysis will facilitate the understanding of genomic diversity and evolution of C. difficile strains in this region.

A genomic update on clostridial phylogeny: Gram‐negative spore formers and other misplaced clostridia

The class Clostridia in the phylum Firmicutes (formerly low-G+C Gram-positive bacteria) includes diverse bacteria of medical, environmental and biotechnological importance. The Selenomonas-Megasphaera-Sporomusa branch, which unifies members of the Firmicutes with Gram-negative-type cell envelopes, was recently moved from Clostridia to a separate class Negativicutes. However, draft genome sequences of the spore-forming members of the Negativicutes revealed typically clostridial sets of sporulation genes. To address this and other questions in clostridial phylogeny, we have compared a phylogenetic tree for a concatenated set of 50 widespread ribosomal proteins with the trees for beta subunits of the RNA polymerase (RpoB) and DNA gyrase (GyrB) and with the 16S rRNA-based phylogeny. The results obtained by these methods showed remarkable consistency, suggesting that they reflect the true evolutionary history of these bacteria. These data put the Selenomonas-Megasphaera-Sporomusa group back within the Clostridia. They also support placement of Clostridium difficile and its close relatives within the family Peptostreptococcaceae; we suggest resolving the long-standing naming conundrum by renaming it Peptoclostridium difficile. These data also indicate the existence of a group of cellulolytic clostridia that belong to the family Ruminococcaceae. As a tentative solution to resolve the current taxonomical problems, we propose assigning 78 validly described Clostridium species that clearly fall outside the family Clostridiaceae to six new genera: Peptoclostridium, Lachnoclostridium, Ruminiclostridium, Erysipelatoclostridium, Gottschalkia and Tyzzerella. This work reaffirms that 16S rRNA and ribosomal protein sequences are better indicators of evolutionary proximity than phenotypic traits, even such key ones as the structure of the cell envelope and Gram-staining pattern.