Methicillin-resistant Staphylococcus aureus (MRSA) in hospitalized children: correlation of molecular analysis with clinical presentation and antibiotic susceptibility testing (ABST) results
The molecular analysis of methicillin-resistant Staphylococcus aureus (MRSA) from 98 children admitted to the Children’s Hospital of Michigan, Detroit, MI, with serious MRSA infections during 2006–2007 was correlated with risk factors, clinical features, and antibiotic susceptibility testing (ABST) results. Isolates were characterized by staphylococcal cassette chromosome (SCC) mec type, the presence of Panton-Valentine leukocidin (PVL) genes, repetitive sequence (rep) polymerase chain reaction (PCR) and pulsed-field gel electrophoresis (PFGE), requirement for surgical intervention, antibiograms, and response to therapy. rep-PCR was more rapid than PFGE typing and correlated well. SCCmec type IV-containing isolates caused 92.8% of all infections, but the demographics and diseases associated with subtypes IVa and IVd differed. Subtype IVa (all PFGE type USA300 and PVL-positive) was identified in 81/93 (87.1%) of patients with community-onset (CO) MRSA, including 21/35 of those with risk factors for health care-associated (HA) infection. All other clones were PVL-negative. Subtype IVd (10 isolates; 9 USA800 and 1 eMRSA15) caused mainly HA-MRSA and no skin and soft tissue infections (SSTI). Seven classic HA-MRSA strains (SCCmec types II [6; 3 USA100 and 3 USA600] and III [1; USA200]) caused HA and hospital-onset (HO) infections. Surgical intervention was required in 68/81 patients infected with USA300 and 8/17 of the others. Most USA300 were susceptible (S) to clindamycin (CD) and patients were treated with CD alone or in combination. The other isolates were generally treated with vancomycin (VA) alone or in combination.
KeywordsLinezolid Daptomycin Mupirocin Chronic Suppurative Otitis Medium SCCmec Type
We thank the Detroit Medical Center University laboratory personnel and the personnel at DiversiLab for their technical help. We also thank the personnel at the Staphylococcus aureus typing laboratory at the Centers for Disease Control and Prevention, Atlanta, GA, for performing the pulsed-field gel electrophoresis.
The study was supported by a grant from Cubist Pharmaceuticals.
- 1.Ross TL, Merz WG, Farkosh M, Carroll KC (2005) Comparison of an automated repetitive sequence-based PCR microbial typing system to pulsed-field gel electrophoresis for analysis of outbreaks of methicillin-resistant Staphylococcus aureus. J Clin Microbiol 43(11):5642–5647. doi: 10.1128/JCM.43.11.5642-5647.2005 PubMedCrossRefGoogle Scholar
- 3.McDougal LK, Steward CD, Killgore GE, Chaitram JM, McAllister SK, Tenover FC (2003) Pulsed-field gel electrophoresis typing of oxacillin-resistant Staphylococcus aureus isolates from the United States: establishing a national database. J Clin Microbiol 41(11):5113–5120. doi: 10.1128/JCM.41.11.5113-5120.2003 PubMedCrossRefGoogle Scholar
- 6.Gonzalez BE, Rueda AM, Shelburne SA 3rd, Musher DM, Hamill RJ, Hulten KG (2006) Community-associated strains of methicillin-resistant Staphylococcus aureus as the cause of healthcare-associated infection. Infect Control Hosp Epidemiol 27(10):1051–1056. doi: 10.1086/507923 PubMedCrossRefGoogle Scholar
- 8.Clinical and Laboratory Standards Institute (CLSI) (2008) Performance standards for antimicrobial susceptibility testing: eighteenth informational supplement. M100-S18. CLSI, Wayne, PA, pp 46–51Google Scholar
- 11.Naimi TS, LeDell KH, Como-Sabetti K, Borchardt SM, Boxrud DJ, Etienne J, Johnson SK, Vandenesch F, Fridkin S, O’Boyle C, Danila RN, Lynfield R (2003) Comparison of community- and health care-associated methicillin-resistant Staphylococcus aureus infection. JAMA 290(22):2976–2984. doi: 10.1001/jama.290.22.2976 PubMedCrossRefGoogle Scholar
- 12.Zhang K, McClure JA, Elsayed S, Louie T, Conly JM (2005) Novel multiplex PCR assay for characterization and concomitant subtyping of staphylococcal cassette chromosome mec types I to V in methicillin-resistant Staphylococcus aureus. J Clin Microbiol 43(10):5026–5033. doi: 10.1128/JCM.43.10.5026-5033.2005 PubMedCrossRefGoogle Scholar
- 13.Blanc DS, Struelens MJ, Deplano A, De Ryck R, Hauser PM, Petignat C, Francioli P (2001) Epidemiological validation of pulsed-field gel electrophoresis patterns for methicillin-resistant Staphylococcus aureus. J Clin Microbiol 39(10):3442–3445. doi: 10.1128/JCM.39.10.3442-3445.2001 PubMedCrossRefGoogle Scholar