Molecular epidemiology of Staphylococcus aureus in post-earthquake northern Haiti

• Northern Haiti has a comparatively low overall S. aureus nasal carriage rate of 11.2% and a low MRSA colonization rate of 2.8%.
• A high tetracycline resistance rate was noted with tetracycline resistance in 66.7% of MSSA isolates and 50% of MRSA isolates.
• Molecular analysis revealed genetic diversity with CC72 and CC5 being the most common clones noted in this population, and PVL was present in 15.8% of all S. aureus carriage strains.

SummaryBackgroundKnowledge of nasal carriage is important in predicting staphylococcal infection, and no information exists regarding the endemicity of Staphylococcus aureus in Haiti.MethodsWe performed a cross-sectional analysis of S. aureus nasal screening in an acute care, a subacute rehabilitation, and a community setting, with a brief medical and epidemiological history. PCR-positive S. aureus screening nasal cultures underwent molecular analysis for spa type, SCCmec type, and virulence genes (Panton–Valentine leukocidin (PVL), toxic shock syndrome toxin (TSST), and arginine catabolic mobile element (ACME)), and were evaluated for antibiotic susceptibility using commercial tests.ResultsOverall carriage rates of 8.4% methicillin-susceptible S. aureus (MSSA) and 2.8% methicillin-resistant S. aureus (MRSA) were identified, with a high rate of tetracycline resistance. TSST and PVL genes were identified in MSSA. MRSA isolates contained no virulence markers. Unique MSSA phenotypes (i.e., linezolid-resistant, vancomycin-sensitive/daptomycin non-susceptible) were identified, as were two PVL-positive ST152 MSSA colonization isolates, previously geographically limited to Africa.ConclusionsWe found a low S. aureus carriage rate with complete vancomycin susceptibility and high tetracycline resistance, which has important public health implications with regard to treatment. Additionally, the finding of PVL-positive MSSA isolates, including the expansion of a previously described limited ‘divergent’ clone, ST152, warrants further evaluation.