Molecular distinctions exist between community-associated methicillin-resistant Staphylococcus aureus colonization and disease-associated isolates in children

• Published in: The Pediatric infectious disease journal Vol. 30; no. 5; p. 418
• Main Authors: Thomsen, Isaac, McKenna, Brian D, Saye, Elizabeth J, Jimenez, Natalia, Edwards, Kathryn M, Creech, C Buddy
• Format: Journal Article
• Language: English
• Published: United States 01.05.2011
• Subjects: Bacterial Proteins - genetics; Bacterial Toxins - genetics; Bacterial Typing Techniques; Bacteriocins - genetics; Carrier State - epidemiology; Carrier State - microbiology; Child; Child, Preschool; Community-Acquired Infections - epidemiology; Community-Acquired Infections - microbiology; Electrophoresis, Gel, Pulsed-Field; Exotoxins - genetics; Humans; Leukocidins - genetics; Methicillin-Resistant Staphylococcus aureus - classification; Methicillin-Resistant Staphylococcus aureus - genetics; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Molecular Epidemiology; Molecular Typing; Penicillin-Binding Proteins; Polymerase Chain Reaction; Staphylococcal Infections - epidemiology; Staphylococcal Infections - microbiology; Trans-Activators - genetics
• ISSN: 1532-0987
• DOI: 10.1097/INF.0b013e31820d7fd5

To define the molecular epidemiology of colonization and disease-associated isolates of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). Laboratory-based comparative study of clinical staphylococcal isolates. We analyzed 255 pediatric CA-MRSA isolates for molecular characteristics associated with colonization and disease. We used polymerase chain reaction to determine the presence of Panton-Valentine Leukocidin and the lantibiotic element, bsaB, and to characterize the staphylococcal cassette chromosome mec type and accessory gene regulator locus. Pulsed-field gel electrophoresis was used to determine genetic relatedness between strains. A total of 150 isolates were obtained from patients with clinical disease (37 invasive infections, 113 noninvasive infections) and 105 from subjects with nasal colonization alone. Of 150 disease-associated isolates, 123 (82%) belonged to pulsed-field gel electrophoresis group USA300, whereas only 19 (18%) of 105 colonization isolates were of the USA300 lineage. Colonization isolates were less likely to possess staphylococcal cassette chromosome mec type IV, Panton-Valentine Leukocidin, or agr type 1 (P < 0.001). Colonization strains of CA-MRSA in children differ significantly from those strains recovered from patients with staphylococcal infections. This suggests that only colonization with specific strain types, rather than methicillin-resistant Staphylococcus aureus colonization in general, increases the risk for CA-MRSA disease.