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Panton-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: ФPVL, Ф108PVL 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., (© 2010 The Authors. Journal Compilation © 2010 European Society of Clinical Microbiology and Infectious Diseases.)

Objectives: Community-associated methicillin-resistant Staphylococcus aureus (MRSA) including those encoding Panton-Valentine leucocidin (PVL) are often described as more susceptible to a range of antibiotics than their hospital-associated counterparts. Recent scattered reports of the emergence of multiresistant PVL-MRSA have highlighted the potential for resistance to emerge. Here we detail polyclonal multiply antibiotic-resistant PVL-MRSA occurring in England., Methods: PVL-MRSA from community-based and hospitalized patients located across England were identified by PCR. Isolates were characterized via MIC determinations, toxin gene profiling, PFGE, SCCmec, spa and agr typing. Multilocus sequence typing (MLST) was performed on selected isolates. Patient demographic and available disease data were retained for analysis., Results: Seventy-six PVL-MRSA isolates resistant to three further classes of antibiotic were identified between 2005 and 2008 from centres in each of the Health Protection Agency's geographic regions in England. Patient demographics were typical for PVL-MRSA, and some travel associations were identified along with clonal spread. One instance of familial transmission in the community was detected. PVL-MRSA belonging to MLST clonal complex (CC) 1 (sequence type 772) were consistently highly resistant; multiply antibiotic-resistant representatives of CCs 5, 8, 22, 59 and 80 were also identified. Ciprofloxacin resistance was common amongst the study isolates (51 of 76 isolates)., Conclusions: Genetically diverse multiply antibiotic-resistant PVL-MRSA were identified, and included representatives of a recently emerged multiresistant clone (dubbed the Bengal Bay clone). Risk factors and disease presentations were typical for PVL-MRSA infections. This work highlights the diminishing utility of ciprofloxacin susceptibility for putative identification of PVL-MRSA.

We aimed to enhance our case ascertainment of meticillin-resistant Staphylococcus aureus encoding Panton-Valentine leucocidin (PVL-MRSA), determine the patient demographic, risk factor and disease associations, and define the clonal diversity amongst isolates referred to the UK Health Protection Agency's Staphylococcus Reference Unit. PVL-MRSA collected during 2005-6 from community-based and hospitalised patients located across England and Wales were identified by polymerase chain reaction (PCR). Representative geographically and temporally unrelated isolates were characterised via toxin gene profiling, SCCmec, spa and agr typing, multilocus sequence typing (MLST) and minimum inhibitory concentration (MIC) determinations. PVL-MRSA were identified from 275 patients. Affected individuals were <1 to 95 years of age (mean 30, median 27 years). Forty-five isolates were from 18 household or community-based clusters and 23 isolates were from outbreaks in healthcare settings. Overall, 58% (n = 161) had skin and soft tissue infections and 9% (n = 25) presented with or developed more serious disease, including eight patients (3%) with necrotising pneumonia, five of whom subsequently died. PVL-MRSA were genetically diverse and harboured SCCmecIV or V(T)/VII. Representatives of MLST clonal complexes (CCs) 8, 30 and 80 were identified the most often. The 275 PVL-MRSA included internationally disseminated community-associated MRSA (CA-MRSA) strains, as well as other minor lineages, and were associated with typical risk factors and disease presentations.