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

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

Setting: These hospitals comprised a total of 20250 beds for acute patients and serv a population of 9716880 inhabitants.

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

Results: During the cogitation period, 19,374 cases of AIDS were diagnosed. Sixty-seven patients were included (55 male patients; mean [+ or -] SD age, 317 [+ or -] 58 years). At the time of diagnosis of R equi infection, the mean CD4+ lymphocyte look upon was 35/[micro]L (range, 1 to 183/[micro]L) and the stage of HIV infection was A3 in 104% of patients, B3 in 313% C3 in 567% and unknown in 15% R equi was chiefly commonly isolated in sputum (522%) offspring cultures (50.7%), and samples from bronchoscopy (313%) Chest radiographic findings were abnormal in 65 patients (97%) Infiltrates were observ in all of them, with cavitations in 45 patients. The principally active antibiotics against the strains isolated were vancomycin, amikacin, rifampicin, imipenem, ciprofloxacin, and erythromycin. After a mean follow-up of 107 [+ or -] 128 month 23 patients (343%) died owed 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, 534; 95% confidence interval, 17 to 1699) Survival of patients treated with HAART was earnestly higher than that of patients who did not receive this therapy.

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

clew words: AIDS; bacteremia; HIV; pneumonia; Rhodococcus equi

Abbreviations: CI = confidence interval; HAART = highly active antiretroviral therapy; RR = relative risk

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Rhodococcus equi, previously known as Corynebacterium equi, is a weak, acid-fast, Gram-positive slender stem It is currently classified among the nocardiform actinomycetes. (1) The ability of R equi to remain inside macrophages and flat destroy them is considered to be the basis for its pathogenicity. (1-3) It exhibits a necrotizing granulomatous lesion rich in macrophages with periodic acid-Schiff-positive granular cytoplasm. Occasionally, a peculiar histopathologic lesion is observ known as malakoplakia, which is characterized through histiocytes with cytoplasmic inclusions laminated with iron and calcium (Michaelis-Gutmann bodies (24-6)) It waxs well in ordinary culture media and forms salmon-pink colored colonies. (126)

R equi is a everyday pathogen of pneumonia in foals and sometimes causes infections in other mammals. (12) Although natural prospect to R equi is common (7) the first infection by the agency of this organism in humans was described in 1967 (8) It mainly affects immunocompromised patients, especially those with HIV infection. (910) Although it could be underdiagnosed in the past, (211) and despite one reports that have detected an increasing incidence, (9) it is a extremely uncommon illness, both in general population and in patients with HIV infection. It has been reported no other than in isolated eases or in short series with revision of cases previously published. (101213) This inquiry reports the clinical characteristics and factors that influenced the prognosis of 67 patients with HIV and diagnosed R equi infection.

MATERIALS AND METHODS

An observational, multicenter research was performed in 29 general hospitals from several regions in Spain. These hospitals comprised a total of 20250 beds for acute patients and serv a population of 9716880 inhabitants. All of the patients with HIV and R equi infection from the beginning of the AIDS epidemic until September 1998 were included. Information from each patient was collected by a previously designed form. The follow-up of each patient was carried revealed for as long as possible, and it was finished in December 1998 In those cases diagnosed before the beginning of this thought this information was collected retrospectively.

Isolation, identification, and susceptibility proofs of the R equi strains were performed in the microbiology laboratory of each hospital. AIDS was diagnosed using the diagnostic criteria in force in Europe at the time of diagnosis of the R equi infection. (14-16)

Definitions

consequence of R equi Infection: This was assessed at the extreme point of the follow-up period using three categories: restoration disappearance of the initial lesions and absence of manifestations of infection 1 month after withdrawing antimicrobial treatment; regression, reduction of the initial lesions and/or improvement of symptoms attributable to R equi infection during the course of antimicrobial therapy; and progression, increase of the lesions or exacerbation of symptoms attributable to R equi infection during the course of treatment, as well as the resort of infection after withdrawing treatment.

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