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Rhodococcus equi infection in patients with AIDS
M Drancourt1, E Bonnet, H Gallais
1Laboratoire de Microbiologie Clinique, Hôpital de la Conception, Marseille, France.
Abstract:
Rhodococcus equi is an emerging opportunistic pathogen of HIV-I infected patients. It is an aerobic, Gram-positive coryneform bacterium which acts as a facultative intracellular micro-organism, multiplying in the phagosome of macrophages. Eighteen cases of R. equi infection in HIV-I positive patients have now been reported. Sixteen of these had pneumonia, of which 12 had cavitating lung lesions. A history of contact with farm animals, which are the primary hosts of R. equi, was found in only three patients. There was a delay in establishing a definite diagnosis in most cases as this depended upon the isolation of R. equi from sputum, bronchoalveolar lavage fluid, or blood. Treatment included surgical resection in five patients and erythromycin with a second antibiotic in 13 cases, but II of the 18 patients died from the infection. In this report we describe our experience of R. equi pneumonia in two AIDS patients and review the published cases of the disease in man.
Insights
Rhodococcus equi is an opportunistic pathogen causing severe pneumonia in HIV-infected individuals. Early diagnosis and treatment are crucial, but mortality remains high, highlighting the need for better management strategies.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Immunology
Background:
- Rhodococcus equi is an opportunistic pathogen.
- It primarily affects immunocompromised individuals, particularly those with Human Immunodeficiency Virus (HIV).
- R. equi is a facultative intracellular microorganism that replicates within macrophages.
Observation:
- Eighteen cases of Rhodococcus equi infection in HIV-positive patients were reported.
- Sixteen patients developed pneumonia, with 12 exhibiting cavitating lung lesions.
- A history of contact with farm animals was reported in only three patients.
Findings:
- Diagnosis was often delayed due to reliance on microbiological isolation from clinical samples.
- Treatment involved surgical resection in some cases and antibiotics (erythromycin plus a second agent) in most.
- Despite treatment, 11 out of 18 patients died from the infection.
Implications:
- Rhodococcus equi poses a significant threat to HIV-infected patients, often leading to severe pneumonia and high mortality.
- The findings underscore the importance of considering R. equi in the differential diagnosis of pulmonary infections in this population.
- Improved diagnostic methods and treatment strategies are needed to reduce the fatality rate associated with R. equi infections.