Volume 3, Number 11;  September 10, 2004

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Resident Report 8/02/04 / Samantha Kraly

Case: 

Patient is a 37yo Caucasian male with AIDS (CD4 count 56) who presents with 4 month history of fevers, night sweats, rigors, profound weight loss, L-sided pleuritic chest pain, and cough productive of bloody sputum.  He had been previously admitted  at which time he was found to have a LUL cavitary lesion.  During the prior admission, he had 3 negative AFB smears and underwent bronchoscopy that yielded negative bacterial cultures, AFB smears, and cytology.  Given the high clinical suspicion for pulmonary TB, the pt was discharged on empiric TB therapy awaiting AFB and fungal cultures.  Pt elected not to take RIPE and was readmitted a month later to an outside hospital for worsening symptoms.  He was again ruled out for TB, started on levofloxacin, and discharged.  He returned to Grady when his symptoms did not improve on levofloxacin.  Upon review of records, his AFB culture from one month prior was negative.

On presentation, patient was febrile with severe rigors.  He had L-sided chest wall tenderness to palpation with crackles and egophany in left upper lung field.  His CXR showed dramatic increase in the size of his cavitary lesion with surrounding consolidation.  He again was admitted to respiratory isolation.  This admission, the AFB smears of his sputum showed a mucoid appearing coccobacilli that weakly stained on flourochrome not histologically typical for tuberculosis.  He underwent bronchoscopy and his BAL cultures grew Rhodococcus equi. 

Clinical Question: 

Who is at risk for infection with Rhodococcus equi, how is it transmitted, and what is effective therapy?

Readings:

Link Directly to Fulltext Article at Publisher

<1>

Unique Identifier:11170969

Authors: Kedlaya I. Ing MB. Wong SS.

Institution: Department of Internal Medicine, Loma Linda University Medical Center, Loma Linda, CA, USA. IKedlaya@yahoo.com

Title: Rhodococcus equi infections in immunocompetent hosts: case report and review. [Review] [30 refs]

Source: Clinical Infectious Diseases. 32(3):E39-46, 2001 Feb 1.

Abstract: Rhodococcus equi is an unusual cause of infection in humans. Infection in immunocompetent patients is extremely rare-only 19 cases in immunocompetent hosts have been reported. Localized infections represent nearly 50% of reported cases. Pulmonary infections account for only 42% of infections in immunocompetent hosts, compared with 84% of infections in immunocompromised hosts. The mortality rate among immunocompetent patients is approximately 11%, compared with rates of 50%-55% among human immunodeficiency virus (HIV)-infected patients and 20%-25% among non-HIV-infected immunocompromised patients. Treatment of infections in immunocompetent hosts depends on the site of infection. Serious infections need to be treated with combinations of parenteral antibiotics, followed by combinations of oral antibiotics. Surgical treatment is necessary for certain types of local infections. We report a pulmonary infection due to R. equi in an immunocompetent patient, and we review all reported cases of R. equi infection in immunocompetent hosts. [References: 30]

<2>

Unique Identifier:8729207

Authors: Gallant JE. Ko AH.

Institution: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-6220, USA.

Title: Cavitary pulmonary lesions in patients infected with human immunodeficiency virus. [Review] [208 refs]

Source: Clinical Infectious Diseases. 22(4):671-82, 1996 Apr.

Abstract: The differential diagnosis of cavitary pulmonary lesions in individuals infected with human immunodeficiency virus (HIV) is broad, especially in patients with advanced disease. In patients with Pneumocystis carinii pneumonia, cavitation is an uncommon manifestation of a common disease. It is unusual in patients with pulmonary cryptococcosis, coccidioidomycosis, and histoplasmosis but occurs frequently in patients with invasive pulmonary aspergillosis. In patients with pulmonary tuberculosis, cavities are more common during earlier stages of HIV disease, when cellular immunity is relatively preserved. Mycobacterium avium complex is an uncommon cause of lung disease and infrequently produces cavities. However, Mycobacterium kansasii, is often associated with cavitation. Cavities can complicate any bacterial pneumonia and are especially common with pneumonia due to Pseudomonas aeruginosa, Nocardia asteroides, and Rhodococcus equi. Noninfectious causes of cavitary lesions are rare, but cavitary lesions caused by pulmonary Kaposi's sarcoma and non-Hodgkin's lymphoma have been reported. Because of the broad differential diagnosis and because most cavities are caused by treatable opportunistic infections, a definitive diagnosis is essential. [References: 208]

<3>

Unique Identifier:1453322

Authors: Magnani G. Elia GF. McNeil MM. Brown JM. Chezzi C. Gabrielli M. Fanti F.

Institution: Divisione di Malattie Infettive, U.S.L. 4 di Parma, Italy.

Title: Rhodococcus equi cavitary pneumonia in HIV-infected patients: an unsuspected opportunistic pathogen.[see comment].

Source: Journal of Acquired Immune Deficiency Syndromes. 5(10):1059-64, 1992 Oct.

Abstract: Two patients seropositive for human immunodeficiency virus (HIV) and with no previous acquired immunodeficiency syndrome-defining conditions developed cavitary pneumonia and pleural disease caused by Rhodococcus equi. R. equi was isolated from these patients' sputum and lung biopsy specimens, respectively, but the microorganism was initially considered to be a contaminant (patient 1) or misidentified as a nontuberculous mycobacterium (patient 2). The R. equi infection was fatal in one patient, who died after 4 months without specific antimicrobial therapy; the second patient was unresponsive to combination therapy with various antimicrobial agents. R. equi may cause life-threatening infections in HIV-infected patients. Microbiology laboratories should be cognizant of the need to exclude R. equi as a cause of infection in highly immunosuppressed patients.

<4>

Unique Identifier:1925723

Authors: Lasky JA. Pulkingham N. Powers MA. Durack DT.

Institution: Department of Medicine, Duke University Medical Center, Durham, NC 27710.

Title: Rhodococcus equi causing human pulmonary infection: review of 29 cases. [Review] [33 refs]

Source: Southern Medical Journal. 84(10):1217-20, 1991 Oct.

Abstract: Rhodococcus equi is a gram-positive pleomorphic bacillus that has been identified as a life-threatening pulmonary pathogen in the immunocompromised host. Infection with R equi may go unrecognized by physicians unacquainted with its presentation and unaware of the organism's ability to mimic diphtheroids and to stain weakly positive with an acid-fast stain. [References: 33]

Resident Report / Department of Medicine & Grady Branch Library

Emory University School of Medicine

2004 Edition

Participating Faculty:  Carlos Del Rio MD  / Joyce Doyle MD / Lorenzo Difrancesco MD /  Monica Adams MD  / Josh Larned MD

Contact: Karl Woodworth