Microbiology
Masoud keykhah; Morteza Karami; Hosseinali Rahdar; Elahe Taki
Volume 26, Issue 5 , November and December 2019, , Pages 627-640
Abstract
The genus Mycobacterium is a group of acid fast bacteria with DNA G+C content of 61-71% and the cell wall containing mycolic acid. According to growth physiology, mycobacteria grouped into two divisions: rapidly-growing and slow-growing mycobacteria. Three groups of mycobacteria exist based on pigment ...
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The genus Mycobacterium is a group of acid fast bacteria with DNA G+C content of 61-71% and the cell wall containing mycolic acid. According to growth physiology, mycobacteria grouped into two divisions: rapidly-growing and slow-growing mycobacteria. Three groups of mycobacteria exist based on pigment production: nonpigmented (nonphotochromogens), photo-chromogens and scotochromogen. Both human obligate pathogens (M. tuberculosis and M.leprae) and opportunistic species exist in mycobacteria genus. There is different kind of mycobacterial infections such asrespiratory infections, lymphatic node and skeletal involvement, dermal and disseminated infection. Spread of HIV virus and immunodeficiency in recent years makes the mycobacterial infections one of the most dangerous infections. Acid fast staining, biochemical tests and cell wall mycolic acid and fatty acid analysis are used for detection of mycobacteria. Different molecular tests including different PCR basedmethods; hybridization and sequencing tests are used for diagnosis and also verifying phenotypic and biochemical tests. Clarithromycin, rifabutin, ciprofloxacin, rifampin and ethambutol currently were used for treatment of slow growing mycobacterial infections. Whereas macrolides, cephalosporins and fluoroquinolones are used for rapidly growing treatment. For rapidly growing mycobacteria, disk diffusion method, disk elution method and broth micro dilution method are more appropriate. Radiometric methods and broth micro dilution method are choice methods for slow growing mycobacteria drug susceptibility test. Moreover molecular methods like PCR single-strand conformational polymorphism (PCR-SSCP), Sequencing, PCR-RFLP and Multiplex-PCR are developed for drug susceptibility determination in mycobacteria. According to non-tuberculosis mycobacteria clinical significance, clinical laboratories and health care team most take attention to diagnosis of these bacterial infections.