BACKGROUND: Within the current worldwide epidemic of community-acquired Staphylococcus aureus infections, attention has focused on the role of methicillin-resistant strains. We characterize methicillin-susceptible strains that also contribute to this epidemic. METHODS: We tracked cultures from abscess specimens submitted to the microbiology laboratory at St. Louis Children's Hospital and examined Panton-Valentine leukocidin (PVL) genes in methicillin-susceptible S. aureus (MSSA) isolates. We further characterized some isolates by multilocus sequence typing, pulsed-field gel electrophoresis, antibiotic susceptibility, accessory gene regulator (agr) allele, and presence of the arcA gene of the arginine catabolic mobile element. RESULTS: From 1999 to 2007, we detected a 250-fold increase in cultures of abscesses yielding methicillin-resistant S. aureus (MRSA) and a 5-fold increase in abscess cultures yielding MSSA. MSSA isolates from abscesses and wounds were more likely to encode PVL than isolates from other sources. In contrast to PVL-negative isolates of MSSA, which were genetically diverse, PVL-positive isolates were predominantly multilocus sequence typing type 8 and agr type 1. More than half of PVL-positive MSSA isolates were resistant to erythromycin and susceptible to clindamycin with the absence of inducible resistance, a pattern uncommon in PVL-negative MSSA but frequent in the USA300 clone of MRSA. In addition, pulsed-field gel electrophoresis of PVL-positive MSSA strains revealed the USA300 pattern. CONCLUSIONS: In addition to methicillin-resistant strains, the current epidemic of S. aureus infections includes infections caused by methicillin-susceptible strains that are closely related genetically and share phenotypic characteristics other than susceptibility to methicillin. These findings suggest that factors other than methicillin resistance are driving the epidemic.
BACKGROUND: Within the current worldwide epidemic of community-acquired Staphylococcus aureus infections, attention has focused on the role of methicillin-resistant strains. We characterize methicillin-susceptible strains that also contribute to this epidemic. METHODS: We tracked cultures from abscess specimens submitted to the microbiology laboratory at St. Louis Children's Hospital and examined Panton-Valentine leukocidin (PVL) genes in methicillin-susceptible S. aureus (MSSA) isolates. We further characterized some isolates by multilocus sequence typing, pulsed-field gel electrophoresis, antibiotic susceptibility, accessory gene regulator (agr) allele, and presence of the arcA gene of the arginine catabolic mobile element. RESULTS: From 1999 to 2007, we detected a 250-fold increase in cultures of abscesses yielding methicillin-resistant S. aureus (MRSA) and a 5-fold increase in abscess cultures yielding MSSA. MSSA isolates from abscesses and wounds were more likely to encode PVL than isolates from other sources. In contrast to PVL-negative isolates of MSSA, which were genetically diverse, PVL-positive isolates were predominantly multilocus sequence typing type 8 and agr type 1. More than half of PVL-positive MSSA isolates were resistant to erythromycin and susceptible to clindamycin with the absence of inducible resistance, a pattern uncommon in PVL-negative MSSA but frequent in the USA300 clone of MRSA. In addition, pulsed-field gel electrophoresis of PVL-positive MSSA strains revealed the USA300 pattern. CONCLUSIONS: In addition to methicillin-resistant strains, the current epidemic of S. aureus infections includes infections caused by methicillin-susceptible strains that are closely related genetically and share phenotypic characteristics other than susceptibility to methicillin. These findings suggest that factors other than methicillin resistance are driving the epidemic.
Authors: D Ashley Robinson; Angela M Kearns; Anne Holmes; Donald Morrison; Hajo Grundmann; Giles Edwards; Frances G O'Brien; Fred C Tenover; Linda K McDougal; Alastair B Monk; Mark C Enright Journal: Lancet Date: 2005 Apr 2-8 Impact factor: 79.321
Authors: Scott K Fridkin; Jeffrey C Hageman; Melissa Morrison; Laurie Thomson Sanza; Kathryn Como-Sabetti; John A Jernigan; Kathleen Harriman; Lee H Harrison; Ruth Lynfield; Monica M Farley Journal: N Engl J Med Date: 2005-04-07 Impact factor: 91.245
Authors: T Ito; Y Katayama; K Asada; N Mori; K Tsutsumimoto; C Tiensasitorn; K Hiramatsu Journal: Antimicrob Agents Chemother Date: 2001-05 Impact factor: 5.191
Authors: G Lina; Y Piémont; F Godail-Gamot; M Bes; M O Peter; V Gauduchon; F Vandenesch; J Etienne Journal: Clin Infect Dis Date: 1999-11 Impact factor: 9.079
Authors: G Prevost; P Couppie; P Prevost; S Gayet; P Petiau; B Cribier; H Monteil; Y Piemont Journal: J Med Microbiol Date: 1995-04 Impact factor: 2.472
Authors: Binh An Diep; Gregory G Stone; Li Basuino; Christopher J Graber; Alita Miller; Shelley-Ann des Etages; Alison Jones; Amy M Palazzolo-Ballance; Françoise Perdreau-Remington; George F Sensabaugh; Frank R DeLeo; Henry F Chambers Journal: J Infect Dis Date: 2008-06-01 Impact factor: 5.226
Authors: Jose-Mario Fontanilla; Kathryn B Kirkland; Elizabeth A Talbot; Kenton E Powell; Joseph D Schwartzman; Richard V Goering; Jeffrey Parsonnet Journal: J Clin Microbiol Date: 2009-12-09 Impact factor: 5.948
Authors: Stephanie A Fritz; Marcus Long; Claude J Gaebelein; Madeline S Martin; Patrick G Hogan; John Yetter Journal: J Sch Nurs Date: 2012-04-03 Impact factor: 2.835
Authors: Stephanie A Fritz; Kristin M Tiemann; Patrick G Hogan; Emma K Epplin; Marcela Rodriguez; Duha N Al-Zubeidi; Juliane Bubeck Wardenburg; David A Hunstad Journal: Clin Infect Dis Date: 2013-02-27 Impact factor: 9.079
Authors: Benjamin A Miko; Cory A Hafer; Caroline J Lee; Sean B Sullivan; Meredith A M Hackel; Brian M Johnson; Susan Whittier; Phyllis Della-Latta; Anne-Catrin Uhlemann; Franklin D Lowy Journal: J Clin Microbiol Date: 2013-01-02 Impact factor: 5.948