Microbiology of osteomyelitis in patients infected with the human immunodeficiency virus

Osteomyelitis rarely develops in patients infected with the human immunodeficiency virus despite their immunosuppressed state. In the limited literature available on this subset of patients, the role of opportunistic micro-organisms is controversial. Our purpose is to describe the microbiologic features of osteomyelitis. This is a retrospective review of 20 patients infected with the human immunodeficiency virus who were admitted to our musculoskeletal infection ward with the diagnosis of osteomyelitis. Eleven patients (55%) were intravenous drug users. Medical comorbidities were present in 14 of 20 patients (70%), including tuberculosis in five patients and hepatitis C in three patients. The mean CD4 count was 269/mm (range, 20-539/mm). Osteomyelitis was monomicrobial in 10 patients (50%) and polymicrobial in seven patients (35%) whereas in three patients no organism was cultured. The most common pathogen was Staphylococcus aureus, present in 10 patients (50%). No mycobacterial or fungal pathogens were identified. Infection recurred in 3 of 14 patients (21%) that were available for followup. Despite their immunocompromised status, patients infected with the human immunodeficiency virus did not develop osseous infections with opportunistic pathogens. Staphylococcus aureus was the most common pathogen found; however, a considerable proportion of infections were polymicrobial.