Genetic variation among Panton-Valentine leukocidin-encoding bacteriophages in Staphylococcus aureus clonal complex 30 strains.
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ABSTRACT: Clonal complex 30 (CC30), one of the major Staphylococcus aureus lineages, has caused extensive hospital-acquired and community-acquired infections worldwide. Recent comparative genomics studies have demonstrated that three CC30 clones-phage type 80/81, Southwest Pacific (SWP), and contemporary EMRSA-16 associated (Con) strains-shared a recent common ancestor more than 100 years ago. Panton-Valentine leukocidin (PVL), a bacteriophage encoded toxin that has been epidemiologically linked with community-associated methicillin-resistant S. aureus (CA-MRSA), has frequently been identified in CC30 clones, although the pvl gene variation and distribution of PVL-encoding phages are poorly understood. We determined here the distribution of PVL phages, PVL gene sequences, and chromosomal phage insertion sites in 52 S. aureus CC30 PVL-harboring isolates, collected from four continents over a 75-year period. Our results indicate that PVL phages with icosahedral heads, including ?108PVL and ?PVL, were mainly associated with phage 80/81 strains, whereas phages with elongated heads were predominantly found in SWP (?Sa2958 and ?TCH60) and Con (?Sa2USA) strains. Nine single-nucleotide polymorphisms were identified in the lukSF-PV gene, with six isolates harboring the R variant that has been previously associated with CA-MRSA strains. Interestingly, all six R variant strains belonged to the same Con CC30 clone and carried a ?Sa2USA-like phage. Similar chromosomal phage insertion sites were also identified in all 52 PVL-harboring CC30 strains. These analyses provide important insights into the microepidemiology of PVL-harboring CC30 strains, while the discovery of ?Sa2USA-associated R variant strains sheds further light on the evolution of PVL-positive CA-MRSA.
SUBMITTER: Chen L
PROVIDER: S-EPMC3592069 | biostudies-literature | 2013 Mar
REPOSITORIES: biostudies-literature
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