Successful treatment of disseminated Mycobacterium haemophilum infection in a patient with AIDS

Clinical manifestations, diagnosis, and treatment of Mycobacterium haemophilum infections

Mycobacterium haemophilum is a slowly growing acid-fast bacillus (AFB) belonging to the group of nontuberculous mycobacteria (NTM) frequently found in environmental habitats, which can colonize and occasionally infect humans and animals. Several findings suggest that water reservoirs are a likely source of M. haemophilum infections. M. haemophilum causes mainly ulcerating skin infections and arthritis in persons who are severely immunocompromised. Disseminated and pulmonary infections occasionally occur. The second at-risk group is otherwise healthy children, who typically develop cervical and perihilar lymphadenitis. A full diagnostic regimen for the optimal detection of M. haemophilum includes acid-fast staining, culturing at two temperatures with iron-supplemented media, and molecular detection. The most preferable molecular assay is a real-time PCR targeting an M. haemophilum-specific internal transcribed spacer (ITS), but another approach is the application of a generic PCR for a mycobacterium-specific fragment with subsequent sequencing to identify M. haemophilum. No standard treatment guidelines are available, but published literature agrees that immunocompromised patients should be treated with multiple antibiotics, tailored to the disease presentation and underlying degree of immune suppression. The outcome of M. haemophilum cervicofacial lymphadenitis in immunocompetent patients favors surgical intervention rather than antibiotic treatment.

Mycobacterium haemophilum osteomyelitis: case report and review of the literature

Background

Mycobacterium haemophilum is a slow-growing, fastidious, iron-requiring microorganism that, relative to other non-tuberculous mycobacterial species, has rarely been documented as a cause of human infection. This microorganism appears to be acquired via environmental exposure although its natural habitat and mode of acquisition are unknown. It has primarily been implicated as a cause of ulcerating cutaneous or subcutaneous nodular skin lesions, particularly in immunocompromised patients, although infections at extracutaneous sites have also been described. Osteomyelitis, while rarely documented, appears to be an important complication of infection with M. haemophilum in these patients.

Case presentation

We describe a unique case of culture-confirmed M. haemophilum osteomyelitis in an adult woman with polycythemia vera and review the world literature on bone infections due to this organism.

Conclusion

Mycobacterium haemophilum is an important but infrequently encountered cause of osteomyelitis in immunocompromised patients, often requiring months to years of medical therapy, with or without surgery, to effect a clinical cure.

Mycobacterium haemophilum infections in heart transplant recipients: case report and review of the literature

Non-tuberculous mycobacteria are becoming increasingly important pathogens among transplant recipients. We report a case of disseminated Mycobacterium haemophilum infection in a heart transplant recipient, manifesting as cellulitis, subcutaneous nodules, septic arthritis, and pneumonitis. Our case illustrates diverse challenges in the identification and treatment of this pathogen, such as its unique culture requirements and variable antimicrobial susceptibilities. Heightened clinical suspicion is necessary to establish a timely diagnosis so that optimal treatment can be administered.

Mycobacterium haemophilum in immunocompromised patients

Mycobacterium haemophilum, a recently described pathogen, can cause an array of symptoms in immunocompromised patients. To date, 90 patients with this infection have been described worldwide. We report our institution's experience with 23 patients who were treated from 1990 through 2000. Fourteen patients had undergone bone marrow transplantation, 5 were infected with human immunodeficiency virus, 3 had hematologic malignancies, and 1 had no known underlying immunosuppression. Clinical syndromes on presentation included skin lesions alone in 13 patients, arthritis or osteomyelitis in 4 patients, and lung disease in 6 patients. Although patients with skin or joint involvement had favorable outcomes, 5 of 7 patients with lung infection died. Prolonged courses of multidrug therapy are required for treatment. A diagnosis of M. haemophilum infection must be considered for any immunocompromised patient for whom acid-fast bacilli are identified in a cutaneous, synovial fluid or respiratory sample or for whom granulomas are identified in any pathological specimen.

The changing spectrum of rheumatic disease in human immunodeficiency virus infection

CONTEXT

Although it has been known for over 15 years that a number of rheumatic diseases occur in patients with human immunodeficiency virus (HIV) infection, increasing knowledge about these disorders and advances in HIV treatment need to be considered in approaching patients with HIV-associated rheumatic disease.

OBJECTIVE

To examine the clinical, pathologic, and therapeutic features of HIV-associated rheumatic diseases in the context of what is known about the immunology of HIV infection.

DATA SOURCES

The author's own extensive collection of references, supplemented by PubMed Medline searches for articles in English-language journals published between 1985 and 2000. The indexing term HIV and the following coindexing terms were used for searching: arthritis, Reiter's syndrome, psoriatic arthritis, rheumatoid arthritis, osteonecrosis, vasculitis, pulmonary hypertension, myositis, myopathy, fibromyalgia, septic arthritis, parotid enlargement, diffuse infiltrative lymphocytosis syndrome, systemic lupus erythematosus, septic arthritis, mycobacterial arthritis, fungal arthritis, autoantibodies, anti-cardiolipin antibodies, and anti-neutrophilic cytoplasmic antibodies.

STUDY SELECTION

All papers identified in the literature search were reviewed. Studies presenting data that merely confirmed previous studies were not included in the analysis.

DATA EXTRACTION

All identified papers were abstracted by the author. Letters to the editor were included only if a new observation had been made.

DATA SYNTHESIS

This was a qualitative review of papers published, with new knowledge about these disorders summarized and presented.

RESULTS

Despite new treatments for HIV, reports of rheumatic diseases presenting in AIDS patients persist, especially in HIV-associated arthritis, diffuse infiltrative lymphocytosis syndrome, HIV-associated vasculitis, and polymyositis. However, new HIV treatments may ameliorate these diseases.

CONCLUSIONS

The spectrum of HIV-associated rheumatic disease remains a diagnostic and therapeutic challenge for the clinician. The impact of changes in HIV treatment on these disorders requires further assessment.

Musculoskeletal infections in patients with human immunodeficiency virus infection

Musculoskeletal infections constitute an unusual clinical manifestation in patients with human immunodeficiency virus (HIV) infection. Available information about patients' characteristics and their clinical course has been obtained mainly from case reports and small retrospective studies. Our retrospective study is the largest in the literature providing detailed information about the clinical and laboratory characteristics of HIV-infected patients with different musculoskeletal infections. We identified 30 patients with various infections of the musculoskeletal system during a 5-year period among a cohort of 3,000-4,000 HIV-infected patients, and we describe them along with all cases of musculoskeletal infections in patients with HIV reported in the literature since 1985. Septic arthritis was the most commonly reported infection of the musculoskeletal system. It usually affects young men with a median CD4 count of 241. The exact contribution of a previous history of intravenous drug abuse in the pathogenesis of septic arthritis is unclear from the present and previous studies. Staphylococcus aureus was the most commonly isolated agent (31.3%). Numerous atypical pathogens were also identified as causes of septic arthritis. Approximately 90% of patients recovered with appropriate antibiotic treatment. Osteomyelitis was a more serious infection which also affected young individuals but with lower CD4 counts (median, 41). Half the cases were due to atypical mycobacteria. The mortality rate in the previously reported cases and in our series was high (20%). Pyomyositis is an increasingly recognized infection of the striated muscles in HIV-infected patients. It affects almost exclusively males with advanced HIV infection (median CD4 count, 24). Most cases are due to Staphylococcus aureus (67%). Drainage of the involved muscle(s) accompanied by proper antibiotic treatment resulted in resolution of the infection in the majority of patients (90%). Although the incidence of musculoskeletal infections in patients with HIV from this and previous studies appears to be low (0.3%-3.5%), these infections add a significant morbidity and mortality in the affected individuals. Better understanding of their pathogenesis and clinical course would aid the proper diagnosis and management of these infections.

Mycobacterial complications of HIV infection

Tuberculosis is the most common opportunistic infection worldwide and is caused by the only readily transmissible pathogen among persons with HIV infection. If treatment is initiated promptly and is supervised appropriately, cure, fortunately, is highly likely. Isoniazid preventive therapy substantially reduces the risk of tuberculosis in persons with HIV infection. Of the nontuberculous mycobacteria, Mycobacterium avium complex (MAC) is the most frequent cause of disease; however, disseminated MAC disease usually is not seen until the CD4+ cell count is less than 50 cells/L. Newer agents, such as the macrolides and rifabutin, form the nucleus of treatment regimens and also are effective in preventing the disease.

Mycobacterium haemophilum: microbiology and expanding clinical and geographic spectra of disease in humans

Reports of the association of Mycobacterium haemophilum with disease in humans have greatly increased. At least 64 cases have now been reported, with symptoms ranging from focal lesions to widespread, systemic disease. The organism is now known to cause primarily cutaneous and subcutaneous infection, septic arthritis, osteomyelitis, and pneumonitis in patients who are immunologically compromised and lymphadenitis in apparently immunocompetent children. Underlying conditions in the compromised patients have included AIDS; renal, bone marrow, and cardiac transplantation; lymphoma; rheumatoid arthritis; marrow hypoplasia; and Crohn's disease. Reports have originated from diverse geographic areas worldwide. The epidemiology of M. haemophilum remains poorly defined; there appears to be a genetic diversity between strains isolated from different regions. The organism is probably present in the environment, but recovery by sampling has not been successful. M. haemophilum has several unique traits, including predilection for lower temperatures (30 to 32 degrees C) and requirement for iron supplementation (ferric ammonium citrate or hemin). These may in the past have compromised recovery in the laboratory. Therapy has not been well elucidated, and the outcome appears to be influenced by the patient's underlying immunosuppression. The organisms are most susceptible to ciprofloxacin, clarithromycin, rifabutin, and rifampin. Timely diagnosis and therapy require communication between clinician and the laboratory.

Treatment of Mycobacterium haemophilum infection in a murine model with clarithromycin, rifabutin, and ciprofloxacin

An animal model of disseminated Mycobacterium haemophilum infection was utilized to compare treatment with azithromycin, ciprofloxacin, rifabutin, and the combination of clarithromycin with rifabutin. Following subcutaneous challenge with M. haemophilum, local and disseminated infection occurred only in immunosuppressed mice. For disseminated infection, ciprofloxacin was relatively ineffective therapy. Clarithromycin and rifabutin alone significantly reduced the tissue burden in the spleen after 4 weeks of therapy. Combination therapy with rifabutin and clarithromycin was superior to 4 weeks of treatment with the individual agents. When immunosuppressed mice were treated for 20 weeks with the combination of rifabutin and clarithromycin, the tissue burden remained reduced in the spleen at 1 month following the completion of therapy. Combined rifabutin and clarithromycin provide effective treatment for M. haemophilum in this model.

Mycobacterium haemophilum: an emerging pathogen

Mycobacterium haemophilum is emerging as a pathogen of immunocompromised patients particularly those with AIDS and organ transplants. Infection has also occurred in healthy children. Adults usually present with cutaneous manifestations, septic arthritis or occasionally pneumonia. Children have perihilar, cervical or submandibular adenitis. The organism grows on mycobacterial media supplemented with ferric ammonium citrate or hemin, incubated at 30 degrees C to 32 degrees C, two to three weeks after inoculation. The most active antimicrobial agents in vitro are amikacin, ciprofloxacin, clarithromycin, rifabutin and rifampin. Development of resistance to the rifamycins has been demonstrated after patients were treated for several months with several antimycobacterial agents, including the rifamycins. Treatment for several months with at least two agents demonstrated to have low MICs for the organism has been shown to be effective.