Prognosis and clinical evaluation of infection caused by Rhodococcus equi in HIV-infected patients: a multicenter study of 67 cases

Abstract

Objective: To assess the clinical characteristics and the factors that influenced the prognosis of patients with HIV and infection caused by Rhodococcus equi.

Design: Observational, multicenter study in 29 Spanish general hospitals.

Setting: These hospitals comprised a total of 20,250 beds for acute patients and served a population of 9,716,880 inhabitants.

Patients: All patients with HIV and diagnosed R equi infection until September 1998.

Results: During the study period, 19,374 cases of AIDS were diagnosed. Sixty-seven patients were included (55 male patients; mean +/- SD age, 31.7 +/- 5.8 years). At the time of diagnosis of R equi infection, the mean CD4+ lymphocyte count was 35/ micro L (range, 1 to 183/ micro L) and the stage of HIV infection was A3 in 10.4% of patients, B3 in 31.3%, C3 in 56.7%, and unknown in 1.5%. R equi was most commonly isolated in sputum (52.2%), blood cultures (50.7%), and samples from bronchoscopy (31.3%). Chest radiographic findings were abnormal in 65 patients (97%). Infiltrates were observed in all of them, with cavitations in 45 patients. The most active antibiotics against the strains isolated were vancomycin, amikacin, rifampicin, imipenem, ciprofloxacin, and erythromycin. After a mean follow-up of 10.7 +/- 12.8 months, 23 patients (34.3%) died due to causes related to R equi infection and 6 other patients showed evidence of progression of the infection. The absence of highly active antiretroviral therapy (HAART) was independently associated with mortality related to R equi infection (relative risk, 53.4; 95% confidence interval, 1.7 to 1,699). Survival of patients treated with HAART was much higher than that of patients who did not receive this therapy.

Conclusions: Infection by R equi is an infrequent, opportunistic complication of HIV infection and occurs during advanced stages of immunodepression. In these patients, it leads to a severe illness that usually causes a bacteremic, cavitary pneumonia, although HAART can improve the prognosis.