HIV and colonization with Staphylococcus aureus in two maximum-security prisons in New York State.

OBJECTIVE: To evaluate the association between HIV and Staphylococcus aureus colonization after confounding by incarceration is removed.

METHOD: A cross sectional stratified study of all HIV infected and a random sample of HIV-uninfected inmates from two maximum-security prisons in New York State. Structured interviews were conducted. Anterior nares and oropharyngeal samples were cultured and S. aureus isolates were characterized. Log-binomial regression was used to assess the association between HIV and S. aureus colonization of the anterior nares and/or oropharynx and exclusive oropharynx colonization. Differences in S. aureus strain diversity between HIV-infected and uninfected individuals were assessed using Simpson's Index of Diversity.

RESULTS: Among 117 HIV infected and 351 HIV uninfected individuals assessed, 47% were colonized with S. aureus and 6% were colonized with methicillin resistant S. aureus. The prevalence of S. aureus colonization did not differ by HIV status (PR = 0.99, 95% CI = 0.76-1.24). HIV infected inmates were less likely to be exclusively colonized in the oropharynx (PR = 0.55, 95% CI = 0.30-0.99). Spa types t571 and t064 were both more prevalent among HIV infected individuals, however, strain diversity was similar in HIV infected and uninfected inmates.

CONCLUSIONS: HIV infection was not associated with S. aureus colonization in these maximum-security prison populations, but was associated with decreased likelihood of oropharyngeal colonization. Factors that influence colonization site require further evaluation.