Clonal expansion accounts for an excess of antimicrobial resistance in Staphylococcus aureus colonising HIV-positive individuals in Lagos, Nigeria

Abstract Nasal colonisation with Staphylococcus aureus is a risk factor for invasive infection in human immunodeficiency virus (HIV)-positive individuals. This study aimed to characterise colonising S. aureus from regions with a high HIV prevalence. Single nasal swabs were taken from a total of 374 HIV-positive and 370 healthy individuals. Overall, 202 S. aureus carriers were detected. Compared with healthy individuals, HIV-positive subjects were more likely to be S. aureus nasal carriers (33% vs. 21%; P  = 0.0001). Isolates from HIV-positive individuals were more often resistant to meticillin (16% vs. 8%; P  = 0.13), chloramphenicol (47% vs. 16%; P P P spa clonal complexes 3772/ST25 and 064/ST8 were significantly more often isolated from HIV-positive individuals and exhibited greater resistance to ciprofloxacin, SXT and chloramphenicol ( spa -CC 3772) or to meticillin ( spa -CC 064), respectively. Panton–Valentine leukocidin gene content was high overall and was equally distributed between isolates from HIV-positive and healthy individuals (33% vs. 30%). Genotypic characteristics of colonising isolates were similar to those reported to cause invasive infection in Nigeria. The HIV pandemic contributes to the evolution of antimicrobial resistance in S. aureus . Measures to contain antimicrobial resistance of S. aureus in Nigeria must target risk groups such as HIV-positive individuals.