Molecular Distinctions Exist Between Community-associated Methicillin-resistant Staphylococcus aureus Colonization and Disease-associated Isolates in Children

作者：Thomsen Isaac; Mckenna Brian D; Saye Elizabeth J; Jimenez Natalia; Edwards Kathryn M; Creech Buddy^*

来源：Pediatric Infectious Disease Journal, 2011, 30(5): 418-421.

DOI：10.1097/INF.0b013e31820d7fd5

• CA-MRSA
• MRSA
• molecular epidemiology
• colonization
• aureus
• S. aureus

Objective: To define the molecular epidemiology of colonization and disease-associated isolates of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA).
Design: Laboratory-based comparative study of clinical staphylococcal isolates.
Methods: 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.
Results: 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).
Conclusions: 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.

• 出版日期2011-5