Molecular epidemiology of endemic Clostridium difficile infection

This is the first study to provide a comprehensive insight into the molecular epidemiology of endemic Clostridium difficile and particularly that associated with a recently recognized epidemic strain. We DNA fingerprinted all C. difficile isolates from the stools of patients with symptomatic antibiotic-associated diarrhoea and from repeated samples of the inanimate ward environment on two elderly medicine hospital wards over a 22-month period. Notably, C. difficile was not recoverable from either ward immediately before opening, but was found on both wards within 1–3 weeks of opening, and the level of environmental contamination rose markedly during the first 6 months of the study period. C. difficile infection (CDI) incidence data correlated significantly with the prevalence of environmental C. difficile on ward B (r = 0·76, P 0·05). We found that RAPD and RS–PCR typing had similar discriminatory power, although, despite fingerprinting over 200 C. difficile isolates, we identified only six distinct types. Only two distinct C. difficile strains were identified as causing both patient infection and ward contamination. Attempts to determine whether infected patients or contaminated environments are the prime source for cross-infection by C. difficile had limited success, as over 90% of C. difficile isolates were the UK epidemic clone. However, a non-epidemic strain caused a cluster of six cases of CDI, but was only isolated from the environment after the sixth patient became symptomatic. The initial absence of this strain from the environment implies patient-to-patient and/or staff-to-patient spread. In general, routine cleaning with detergent was unsuccessful at removing C. difficile from the environment. Understanding the epidemiology and virulence of prevalent strains is important if CDI is to be successfully controlled

Emergence and spread of predominantly community-onset Clostridium difficile PCR ribotype 244 infection in Australia, 2010 to 2012

We describe an Australia-wide Clostridium difficile outbreak in 2011 and 2012 involving the previously uncommon ribotype 244. In Western Australia, 14 of 25 cases were community-associated, 11 were detected in patients younger than 65 years, 14 presented to emergency/outpatient departments, and 14 to non-tertiary/community hospitals. Using whole genome sequencing, we confirm ribotype 244 is from the same C. difficile clade as the epidemic ribotype 027. Like ribotype 027, it produces toxins A, B, and binary toxin, however it is fluoroquinolone-susceptible and thousands of single nucleotide variants distinct from ribotype 027. Fifteen outbreak isolates from across Australia were sequenced. Despite their geographic separation, all were genetically highly related without evidence of geographic clustering, consistent with a point source, for example affecting the national food chain. Comparison with reference laboratory strains revealed the outbreak clone shared a common ancestor with isolates from the United States and United Kingdom (UK). A strain obtained in the UK was phylogenetically related to our outbreak. Follow-up of that case revealed the patient had recently returned from Australia. Our data demonstrate new C. difficile strains are an on-going threat, with potential for rapid spread. Active surveillance is needed to identify and control emerging lineages

Molecular epidemiology of Clostridioides (previously Clostridium) difficile isolates from a university hospital in Minas Gerais, Brazil.

The molecular epidemiology of 38 non-duplicate toxigenic Clostridioides (previously Clostridium) difficile isolates from inpatients from a hospital in Brazil during a 6-year period (2012-2017) were investigated by multilocus sequence typing (MLST) and ribotyping. These isolates were classified into 20 sequence types (ST), six (30%) of which were novel, revealing a high diversity in a single hospital. Classic hypervirulent strains ST1/RT027 and ST11/RT078 were not identified, while ST42 (almost all RT106) was the most common type, being detected in 11 (28.9%) strains. Noteworthy, six (15.8%) isolates were classified into five STs from clade 2, four of which were new ST and RT. Our study suggests that possible hypervirulent strains other than ST1/RT027 might be inadvertently circulating in Brazilian hospitals and highlights the importance of permanent surveillance on circulating strains in a national scale