Frequency of Rapid Growing Mycobacteria among Tuberculosis Suspected Patients in Basra- Iraq

Objective: The purpose of this study was to estimate the frequency of rapid growing mycobacteria among tuberculosis suspected patients in Basra governorate and study their resistance to drugs. Methods: A total of 150 sputum samples were obtained from 150 suspected patients who attended the Advisory Clinic for Chest Diseases and Respiratory (ACCDR) in the Basra Governorate from 01/03/2013 to 1/02/2014. Smears were stained with the Ziehl Neelsen technique and specimens were inoculated on Lowenstein Jensen medium, Identification to species level was achieved on the basis of the growth characteristics, pigment production and conventional biochemical tests. Drug susceptibility was tested to rifampicin, ethambutol, pyrazinamide, isoniazid, and streptomycin using the proportional method. Results: From 150 sputum samples, 23 isolates were Mycobacterium tuberculosis (MTB) (15.33%) and 16 (10.66%) were nontuberculous mycobacteria, seven isolates of them (43.75%), 2 males and 5 females, mean age 40 years, were identified using biochemical tests as rapid growing mycobacteria of which 4 (25%) as M. chelonae, 2 (12.5%) M. abscessus and 1 (6.2%) M. smegmatis. In addition to that, the bacteria were successfully differentiated by Duplex-PCR, as MTB and NTM based on amplification of rpoB gene sequences. Sequencing of 16S rDNA showed matching with 6 biochemically identified ones, and one of the 4 M. chelonae was M. chitae. Drug susceptibility testing showed that one M. abscessus isolate appeared to be resistant to all antibiotics (TDR), while two isolates of M. chelonae showed resistance to ethambutol and rifampicin, while M. smegmatis showed weak resistance to pyrazinamide and resistance to rifampicin. Also, all isolates of M. chelonae were sensitive to pyrazinamide, isoniazid and streptomycin. Conclusion: It appears that the rapidly growing mycobacteria represents a high frequency, among nontuberculosis detected patients, which requires phenotypical and genotypical confirmation on a follow-up, along with the examination of patterns of sensitivity. Implementing Duplex-PCR proved to be decisive for differentiating NTM from MTB.