Multiple-locus VNTR Analyses of Methicillin-resistant Staphylococcus aureus from Jamaica

BACKGROUND This study assessed the antimicrobial susceptibilities and the presence of inducible macrolide-lincosamide-streptogramin B (iMLSB) resistance in methicillin-resistant Staphylococcus aureus (MRSA) of Jamaica as well as the relatedness using polymerase chain reaction-based staphylococcal cassette chromosome mec (SCCmec) and multiple-locus variable numbers of tandem repeat analyses (MLVAs). MATERIALS AND METHODS Antimicrobial susceptibility, the presence of MLSB resistance, and SCCmec and MLVA patterns were assessed for 61 nonduplicate isolates of MRSA from hospitalized patients. RESULTS While no isolate was resistant to vancomycin, 53 (86.9%) isolates were resistant to ciprofloxacin, 52 (85.3%) to erythromycin, 49 (80%) to lincomycin, and 45 (74%) to clindamycin. Of the 52 erythromycin-resistant isolates, 48% exhibited constitutive resistance and 8% showed inducible MLSB (iMLSB) resistance. Most (85%) of typable isolates were SCCmec type IV, and among these, 16 MLVA patterns were identified. CONCLUSION Multidrug resistance continues to characterize MRSA. Among the erythromycin-resistant isolates, constitutive resistance and iMLSB resistance are common. These facts will complicate the treatment of MRSA infections and warrant continued surveillance and judicial use of antimicrobial agents.