title: Genetic variation among Panton-Valentine leukocidin-encoding bacteriophages in Staphylococcus aureus clonal complex 30 strains.
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 Φ108PVL and ΦPVL, were mainly associated with phage 80/81 strains, whereas phages with elongated heads were predominantly found in SWP (ΦSa2958 and ΦTCH60) and Con (ΦSa2USA) 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 ΦSa2USA-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 ΦSa2USA-associated R variant strains sheds further light on the evolution of PVL-positive CA-MRSA.
authors.affiliation: Public Health Research Institute Center, International Center for Public Health, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.forename: Kalyan D
authors.initials: KD
authors.lastname: Chavda
authors.forename: Mihir
authors.initials: M
authors.lastname: Solanki
authors.forename: José R
authors.initials: JR
authors.lastname: Mediavilla
authors.forename: Barun
authors.initials: B
authors.lastname: Mathema
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Schlievert
authors.forename: Barry N
authors.initials: BN
authors.lastname: Kreiswirth
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics*; D002876:Chromosomes, Bacterial; D005098:Exotoxins / Q000235:genetics*; D014644:Genetic Variation; D006801:Humans; D007956:Leukocidins / Q000235:genetics*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification / Q000821:virology*; D013204:Staphylococcus Phages / Q000145:classification / Q000235:genetics* / Q000648:ultrastructure; D014771:Virion / Q000648:ultrastructure; D016662:Virus Integration
chemical_list: D001427:Bacterial Toxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin