1691. Rhodococcus equi in Immunocompromised and Immunocompetent Individuals and Antibiotic Susceptibility of Clinical Isolates:  A Case Series of 12 Patients with Literature Review
Session: Poster Abstract Session: HIV: Other Opportunistic Infections in HIV
Saturday, October 10, 2015
Room: Poster Hall
Posters
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  • Background:

    Rhodococcus equi is an unusual zoonotic pathogen that can cause pneumonia in susceptible hosts.  Twelve cases of R. equi infection were identified at a tertiary care center in central Kentucky.   These patients were compared to cases reported in the literature, and an empiric treatment regimen for R. equi infection proposed.

    Methods:

    Following IRB approval, patients with R. equi infection were identified by a SUNQUEST Epi computer search and the charts were reviewed.   A literature search for publications with at least 10 cases of R. equi infection identified 4 studies from Europe and 2 studies from the United States (US) representing 137 cases.   Current and previously reported cases were analyzed for clinical manifestations, prognosis, and susceptibility of R. equi isolates to antibiotics. 

    Results:

    In the series of 12 cases of R. equi infection from Kentucky, all 8 immunocompromised patients (6 HIV-positive and 2 organ transplants) and 2 immunocompetent patients presented with pneumonia at initial diagnosis.  Although the lungs were the primary site of infection in immunocompromised patients, extrapulmonary involvement only was more common in immunocompetent patients (p <0.0001).  Mortality in R. equi-infected HIV patients was lower in the HAART era (8%) than in pre-HAART era (56%) (p<0.0001), suggesting that HAART improves prognosis in these patients.

    In patients for whom susceptibility test results were available, 85%-100% of isolates were susceptible to vancomycin, erythromycin/clarithromycin, rifampin, aminoglycosides, ciprofloxacin and imipenem.  In contrast, 0-14% of isolates were susceptible to penicillin, ampicillin, cephalothin oxacillin, and clindamycin.   Of interest, there was a marked difference in susceptibility of R. equi to co-trimoxazole between the isolates from Europe (35/76; 46%) and those from the US (15/15; 100%) (p<0.0001). 

    Conclusion:

    The clinical presentation for R. equi infection differed for immunocompromised and immunocompetent patients. Empiric treatment of R.equi infection should include a combination of two antibiotics, preferably selected from vancomycin, clarithromycin/azithromycin, ciprofloxacin, rifampin or co-trimoxazole. Co-trimoxazole may be a therapeutic option in the US, but not Europe.

    Praveen Gundelly, MD, ID Consultants Inc, Middleburg Heights, OH

    Disclosures:

    P. Gundelly, None

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