Clinical features; diagnosis; therapy; and prevention of Rhodococcus equi infections
- Leonard N Slater, MD
Leonard N Slater, MD
- Professor of Medicine
- Health and Sciences Center
- University of Oklahoma
Rhodococcus equi once rarely produced human infection. The first case was reported in 1967 , and only 12 additional cases were recorded in the next 15 years . While still not commonplace, R. equi has increasingly been appreciated, especially as an opportunistic pathogen. Most human infections have been associated with immune system dysfunction, and a dramatic increase occurred early in the HIV pandemic [3-12]. Concurrently, increasing recognition of R. equi as a pathogen has led to improved laboratory identification of infections in both immunocompromised and normal humans.
The clinical manifestations, diagnosis, treatment, and prevention of R. equi infections will be reviewed here. The microbiology, pathogenesis, and epidemiology of R. equi infections are discussed separately. (See "Microbiology, epidemiology, and pathogenesis of Rhodococcus equi infections".)
CLINICAL FEATURES OF HUMAN DISEASE
The majority of R. equi infections have occurred in adults, but infection in children as young as nine months old has been reported. Most cases have been observed in men, which is probably partially explained by the predominance of HIV infection in men from North America and Europe, the source of a majority of the R. equi case reports . Nevertheless, cases have now been identified from virtually every continent.
The sites of infection and the specimens from which R. equi can be isolated include, in a roughly declining order of frequency [3-12]:
- Pulmonary (usually the primary site of infection) - sputum, bronchial washings, lung tissue or abscess contents, pleural fluid (empyema)
- Blood (predominantly dissemination from lung infection)
- Central nervous system (predominantly hematogenous spread) - brain abscesses, cerebrospinal fluid
- Subcutaneous and other soft tissue or organ abscesses (predominantly hematogenous spread)
- Wound drainage, infected joints, vitreous fluid (usually due to traumatic inoculation)
- Implanted indwelling devices such as peritoneal dialysis and intravenous catheters
- Other sites such as pharynx, middle ear, lymph nodes, bone, and stool.
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