Prevalence, serotypes, and risk factors for pneumococcal carriage among HIV-infected adults.

From March 2000 through April 2001, 385 HIV-positive individuals were evaluated to determine the prevalence of Streptococcus pneumoniae nasopharynx carriage, to determine antimicrobial susceptibility and serotypes, and to study factors associated with carriage. Each patient was interviewed, and a nasopharyngeal culture, HIV viral load, and CD4 lymphocyte count were obtained. Of 385 patients studied, 64 were carriers of S. pneumoniae (17%). Intermediate susceptibility to penicillin occurred in 18 isolates (28%) and there were no resistant isolates; 50% of the isolates belonged to 3 serotypes (14, 6B, and 9V). One isolate belonged to clone Spain(9V)-3. Tobacco use and intravenous illicit drugs were associated with carriage; HIV viral load and CD4 lymphocyte level were not significantly associated with carriage. The use of the same unaltered antiretroviral regimen for a year or more was associated with a lower risk of colonization, suggesting that prolonged use of highly effective antiretroviral therapy lowers pneumococcal carriage and may lower the risk of infection.