CD4 and AIDS: Prior epidemiologic studies have found that lack of trimethoprim-sulfamethoxazole use, AIDS, low CD4 count, and specific sociodemographic factors (homelessness, recent incarceration) [4,9,10,31,39,40] are associated with MRSA colonization, but these findings were not seen in our study, perhaps due to small sample size and our relatively healthy, homogenous military-based population.