Full text loading...
Chapter 42 : Other Nontuberculous Mycobacteria
Category: Clinical Microbiology; Bacterial Pathogenesis
Ebook: Choose a downloadable PDF or ePub file. Chapter is a downloadable PDF file. File must be downloaded within 48 hours of purchase
The list of clinically important nontuberculous mycobacteria (NTM) is growing as new species continue to be identified and older ones are found to be pathogenic. Molecular techniques such as real-time PCR and gene amplification and restriction length polymorphism are promising tools for rapid identification of NTM. Optimal therapy for a documented Mycobacterium gordonae infection remains undefined. The majority of isolates tested have been resistant in vitro to isoniazid and pyrazinamide, whereas many are susceptible to ethambutol, rifampin, clarithromycin, linezolid, and the fluoroquinolones. Unlike other nontuberculous mycobacteria, M. simiae produces niacin and thus may be confused with M. tuberculosis. M. simiae can colonize the respiratory tract, and the lung is the most commonly reported site of infection. The majority of reported infections have occurred in persons living near rivers or stagnant bodies of water. A recent open-label randomized trial conducted in Ghana compared two regimens for early, limited M. ulcerans infections. In this study, 73 of 76 patients who received streptomycin and rifampin for 8 weeks and 68 of 75 patients who received 4 weeks of streptomycin and rifampin followed by 4 weeks of rifampin and clarithromycin had healed lesions at 1 year after the start of treatment. Infections with M. xenopi have shown variable responses to drug therapy. Recommendations for initial therapy include isoniazid, a rifamycin, ethambutol, and clarithromycin with or without an initial course of streptomycin. Pyrazinamide and ciprofloxacin have been included in some successful regimens.
Key Concept Ranking
- 16s rRNA Sequencing
Nontuberculous mycobacterial infection sites and etiologic species