Incidence and determinants of Pseudomonas aeruginosa infection among persons with HIV: Association with hospital exposure

Abstract Background: Little information exists on risk factors for Pseudomonas aeruginosa infection in persons with HIV. We assessed the incidence and factors associated with P aeruginosa among persons with HIV enrolled in a large observational cohort study in Los Angeles. Methods: Data were analyzed from 4825 persons aged ≥13 years with HIV infection enrolled from 4 outpatient facilities from 1990 to 1998. The association between P aeruginosa infection and demographic, risk behavior, and clinical factors was assessed. Results: P aeruginosa was diagnosed in 72 (1.5%) patients representing a crude incidence rate of 0.74 per 100 person-years. The most frequent site of infection was pulmonary (47%). In multivariate analysis, prior hospitalization (adjusted rate ratio = 7.9, 95% CI, 3.8-16.2), and both dapsone (adjusted rate ratio = 4.0, 95% CI, 2.2-7.4) and trimethoprim-sulfamethoxazole (adjusted rate ratio = 2.5, 95% CI, 1.2-5.3) use were independently associated with higher rates of infection. Increasing days of inpatient stay ( P + counts ( P P aeruginosa. Azithromycin use decreased the risk of infection by nearly 70%. Conclusion: Although the overall observed incidence of P aeruginosa was low, hospital exposure, declining CD4 + levels, and the use of dapsone or trimethoprim-sulfamethoxazole increased the risk of P aeruginosa disease, and azithromycin use was protective in this population. These findings may assist in the early recognition and diagnosis of persons likely to be at increased risk of P aeruginosa infection. (AJIC Am J Infect Control 2001;29:79-84)