Infectious Diseases: Research and Treatment

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 MLSв (iMLSв) 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 iMLSв resistance are common. These facts will complicate the treatment of MRSA infections and warrant continued surveillance and judicial use of antimicrobial agents.