Management of opportunist mycobacterial infections: Joint Tuberculosis Committee Guidelines 1999. Subcommittee of the Joint Tuberculosis Committee of the British Thoracic Society

Human immunodeficiency virus type 1-related pulmonary Mycobacterium xenopi infection: a need to treat?

We report treatment decisions and outcomes for 20 patients who were infected with human immunodeficiency virus type 1 (HIV-1) and were receiving highly active antiretroviral therapy (HAART) who had respiratory symptoms and from whom Mycobacterium xenopi was isolated. All patients also had coexisting pulmonary pathologic conditions. The median blood T cell CD4 count was 37 cells/microL (range, 2-480 cells/microL). Fifteen of 20 patients received no antimycobacterial therapy and remain healthy after a median of approximately 4 years of follow-up, and 2 patients required treatment specifically for M. xenopi infection, both showing clinical improvement. We conclude that pulmonary M. xenopi isolation in HIV-1 patients receiving HAART does not usually require specific treatment.

Nontuberculous mycobacterial pulmonary diseases in immunocompetent patients

Nontuberculous mycobacterial (NTM) infections are an increasingly recognized cause of chronic lung disease in immunocompetent adults, and the M. avium complex, M. kansasii, and a rapidly growing mycobacteria such as M. abscessus, M. fortuitum, and M. chelonae account for most of the pathogens involved. Because the clinical features of NTM disease are not distinguishable from those of tuberculosis, and NTM are ubiquitous in the environment, diagnosis requires that the bacilli are isolated and identified. NTM diseases have been difficult to treat, though since the introduction of new macrolides, the outcome for patients with some NTM diseases has improved significantly. For correct diagnosis and the successful treatment of NTM pulmonary disease, a knowledge of the full spectrum of clinical and radiological findings is important.

Comparison of the Automated Mycobacteria Growth Indicator Tube System (BACTEC 960/MGIT) with Löwenstein-Jensen medium for recovery of mycobacteria from clinical specimens

We examined whether the BACTEC/Mycobacteria Growth Indicator Tube (MGIT) system alone could supplant the use of a supplemental Löwenstein-Jensen (LJ) slant for routine recovery of Mycobacterium species from clinical specimens. A total of 6,062 specimens were included in the study. Of these, 273 specimens were positive for 278 mycobacterial isolates while 15 specimens were smear positive but culture negative using both media. Further analysis showed that 143 (51.4%) of the 278 total isolates were recovered from both the MGIT and LJ media. An additional 106 isolates (38.1%) were recovered from the MGIT only, while 29 (10.4%) isolates grew only on the LJ slant. The overall sensitivities of the MGIT and LJ media were 86.5% and 59.7%, respectively, for the recovery of mycobacteria from clinical materials. This study shows that although the MGIT system demonstrates better sensitivity for the recovery of mycobacteria from clinical specimens, both media types are necessary to maximize the sensitivity of detection.

When typical is atypical: mycobacterial infection mimicking cutaneous vasculitis

Patients with systemic lupus erythematosus (SLE) who present with skin disease pose the clinician with diagnostic challenges. The skin disease can reflect an increase in systemic disease activity suggested by other features of active lupus and, as such, usually responds well to more aggressive immunosuppressive therapy. Other possibilities of skin disease include drug eruptions, skin disease unrelated to SLE and, more rarely, opportunistic skin infection. In patients who show a poor response to more aggressive immunosuppressive therapy, consideration must be given to the possibility of opportunistic infection. A high index of suspicion will allow prompt treatment. We describe two patients with SLE who developed cutaneous atypical mycobacterial infection during immunosuppressive therapy. The diagnosis of cutaneous vasculitis was considered in both cases, but subsequent skin biopsy revealed the correct diagnosis. This report illustrates the importance of skin biopsy in patients with suspected cutaneous lupus who are not responding to immunosuppressive therapy.

Non-tuberculous mycobacterial pulmonary infections

Pulmonary disease due to EM occurs worldwide, and its prevalence has increased as a consequence of the HIV pandemic. It is not often detected in the tropics owing to a lack of laboratory facilities, but when sought it has been found. In addition to HIV infection certain occupations such as mining render the work force more susceptible to disease and calls for a revision of working conditions. Resolution by therapy can be achieved in many cases. As the prevalence of TB diminishes worldwide--and hopefully it will in the wake of the resurgence of interest and the widespread application of the World Health Organization's Directly Observed Therapy Short Course (DOTS) strategy--disease due to EM will become relatively more important and will necessitate revised strategies in clinical, microbiological, and public health approaches to mycobacterial disease.

Infection and disease caused by environmental mycobacteria

Many species of mycobacteria that normally live as environmental saprophytes, the environmental mycobacteria (EM), are opportunist causes of disease in humans and animals. Many, but not all, cases are associated with some form of immune deficiency. An increasing number of species and clinical presentations are being described, and advances are being made in the understanding of the underlying predisposing factors. In recent years, four aspects of EM disease have become particularly relevant to human health: (1) the high prevalence of EM disease in patients with AIDS; (2) the emergence of Buruli ulcer, an ulcerative skin disease caused by Mycobacterium ulcerans, as the third most prevalent mycobacterial disease; (3) the effect of infection by EM on the immune responses to BCG vaccination and on the course and outcome of tuberculosis and leprosy; (4) the controversy over the involvement of mycobacteria, notably M. avium subspecies paratuberculosis, in human inflammatory bowel disease. These aspects change the status of EM from mere curiosities to important direct, indirect, and putative causes of serious and increasingly common human disease.

Idiosyncratic rifabutin-induced leukopenia and SIADH: case report and review

Rifabutin is increasingly critical for treatment of atypical mycobacterial infections. One of its serious adverse effects is leukopenia. When encountering rifabutin-induced leukopenia, clinicians are faced with the dilemma of whether to lower the dosage of rifabutin or discontinue it because existing literature does not indicate whether rifabutin-induced leukopenia is dose related or idiosyncratic. We report the first established case of idiosyncratic rifabutin-induced leukopenia in an immunocompetent man treated for pulmonary Mycobacterium avium complex infection. The patient also developed rifabutin-induced syndrome of inappropriate antidiuretic hormone (SIADH), which also has not been previously reported.