Molecular diversity within clonal complex 22 methicillin-resistant Staphylococcus aureus encoding Panton–Valentine leukocidin in England and Wales

AbstractPanton–Valentine leukocidin (PVL)-positive methicillin-resistant Staphylococcus aureus (MRSA) that are multi-locus sequence type clonal complex 22 (CC22) comprise a significant public health problem in the UK. In the present study we sought to determine the genetic diversity, and the respective patient demographics, among 47 PVL-MRSA with a CC22 pulsotype that occurred sporadically or in clusters in community and healthcare settings in eight of nine geographic regions in England and Wales between January 2005 and September 2007. Patient demographics and disease presentations were typical for PVL-S. aureus infections (mostly skin and soft tissue infections in individuals <40 years old); one patient with community-acquired pneumonia died. Although the isolates were closely genotypically related by spa typing and pulsed field gel electrophoresis, at least two variant groups were suggested. PCR detections demonstrated that the majority of the CC22 PVL-MRSA identified (n = 42; 89%) harboured SCCmecIVc, three had SCCmecIVd, one had SCCmecIV but was non-subtypeable, and one isolate harboured SCCmecV. At least three different PVL-encoding phages were detected: ΦPVL, Φ108PVL and an unidentified icosahedral phage. Agar dilution MIC determinations showed that the CC22 PVL-MRSA identified were typically resistant to gentamicin and trimethoprim (43 of 47 isolates) and ciprofloxacin resistance was also noted in six isolates. In conclusion, the CC22 PVL-MRSA tested were geographically disseminated but highly genetically related. The observed variances in acquired elements (most notably SCCmec and PVL-encoding phages) suggested that CC22 PVL-MRSA in England and Wales have evolved on multiple occasions

Whole-genome sequencing reveals widespread presence of Staphylococcus capitis NRCS-A clone in neonatal units across the United Kingdom

OBJECTIVE: Increased incidence of neonatal Staphylococcus capitis bacteraemia in summer 2020, London, raised suspicion of widespread multidrug-resistant clone NRCS-A. We set out to investigate the molecular epidemiology of this clone in neonatal units (NNUs) across the UK. METHODS: We conducted whole-genome sequencing (WGS) on presumptive S. capitis NRCS-A isolates collected from infants admitted to NNUs and from environmental sampling in two distinct NNUs in 2021. Previously published S. capitis genomes were added for comparison. Genetic clusters of NRCS-A isolates were defined based on core-genome single-nucleotide polymorphisms. RESULTS: We analysed WGS data of 838S. capitis isolates and identified 750 NRCS-A isolates. We discovered a possible UK-specific NRCS-A lineage consisting of 611 isolates collected between 2005-2021. We determined 28 genetic clusters of NRCS-A isolates, which covered all geographical regions in the UK, and isolates of 19 genetic clusters were found in ≥2 regions, suggesting inter-regional spread. Within the NRCS-A clone, strong genetic relatedness was identified between contemporary clinical and incubator-associated fomite isolates and between clinical isolates associated with inter-hospital infant transfer. CONCLUSIONS: This WGS-based study confirms the dispersion of S. capitis NRCS-A clone amongst NNUs across the UK and urges research on improving clinical management of neonatal S. capitis infection

Irish-1 and Irish-2: UK epidemic meticillin-resistant Staphylococcus aureus strains associated with Northern Ireland

Since 1998, an increasing number of meticillin-resistant Staphylococcus aureus (MRSA) isolates with one of two characteristic phage patterns have been referred to the authors\u27 laboratory from Northern Ireland. These strains were designated \u27Irish-1\u27 and \u27Irish-2\u27. Analysis of 956 submitted isolates classified as Irish-1 or Irish-2 showed that 97% of the former and 95% of the latter were from Northern Ireland. Only 0.2% and 3%, respectively, were from England. Eleven Irish-2 isolates had been referred from Western Australia as representatives of an epidemic strain originally isolated there in 1994. Ninety isolates with the Irish-1 phage pattern and 91 isolates with the Irish-2 phage pattern, from numerous hospitals, were characterized by SmaI pulsed-field gel electrophoresis (PFGE), toxin gene carriage and antibiotic susceptibility. PFGE showed that, within each collection, a few isolates represented unrelated strains, but the majority were within six band differences of the most common profiles. Half of the Irish-1 isolates were homogeneous, with 22 DNA profiles among the remainder. Irish-2 isolates had two common profiles, D1 and D2, equally divided between one-third of the isolates and differing from each other by two bands; the remaining isolates shared 31 DNA profiles. Cluster analysis showed some overlap in DNA profiles between the Irish-1 and Irish-2 strains, but clear separation from other epidemic MRSA strains. There was no obvious correlation between PFGE profile and either antibiotic resistance pattern or toxin gene possession. All but three Irish-1 isolates possessed only the staphylococcal enterotoxin A (sea) gene, whereas almost all Irish-2 isolates were negative for all 12 enterotoxin genes. Sixty-nine percent of Irish-2 isolates were resistant to ciprofloxacin, erythromycin, kanamycin, neomycin and streptomycin, while 90% of Irish-1 isolates were resistant to all these plus gentamicin and mupirocin. All isolates were sensitive to quinupristin/dalfopristin, teicoplanin and vancomycin. Urease production was negative in both strains. The results suggest that Irish-1 and Irish-2 are distinct epidemic strains, identifiable by phage typing, DNA profiles, antibiotic resistance and toxin gene carriage. © 2006 The Hospital Infection Society

Evaluation of the Biolog GN system Identification of clinically important bacteria

SIGLEGBUnited Kingdo

Clinical, molecular and epidemiological description of a cluster of community-associated methicillin-resistant Staphylococcus aureus isolates from injecting drug users with bacteraemia

AbstractCommunity-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an increasing problem, predominantly in previously healthy individuals including notable risk groups such as the homeless, those who play close-contact sports, military personnel, men who have sex with men (MSM) and injecting drug users (IDUs). Over a 5-month period, four IDUs were admitted to Addenbrooke's Hospital, Cambridge, UK, with MRSA bacteraemia. All four patients presented with complex clinical features, with more than one focus of infection, and were linked epidemiologically. The atypical antibiogram of the MRSA isolates (ciprofloxacin-susceptible) prompted further characterization, both phenotypically (antibiotic resistance typing; phage typing) and genotypically (detection of toxin genes by PCR; pulsed-field gel electrophoresis (PFGE); Staphylococcal chromosome cassette (SCC) mec typing; multi-locus sequence typing (MLST)). All four isolates had similar antibiograms, were Panton-Valentine Leucocidin (PVL) toxin gene-negative, harboured SCCmec type IV and were closely related as shown by phage typing and PFGE. These isolates were representatives of a community-associated clone, ST1-MRSA-IV, known to be circulating in IDUs in the UK since 2001. This paper presents a detailed description of the clinical, microbiological and epidemiological features of a series of CA-MRSA bacteraemias in IDUs in the UK