HSP65-PRA identification of non-tuberculosis mycobacteria from 4892 samples suspicious for mycobacterial infections

Abstract

Various molecular methods have been used for the rapid identification of mycobacterial species. In this survey, evaluation of antibiotic resistance and PCR-restriction fragment length polymorphism analysis (PRA) of the hsp65 gene was carried out for identification of non-tuberculosis mycobacteria (NTM) isolates from different clinical specimens. Forty-eight different mycobacterial isolates were selected and followed by the conventional and PRA of hsp65 for species identification. The antibiotic susceptibility test was carried out according to standard methods. A 439 bp PCR product of hsp65 in all selected isolates was amplified and digested with the BstEII and HaeIII restriction enzymes. The restriction fragment length polymorphism (RFLP) patterns were analyzed for species identification. Using PRA for 48 mycobacterial selected isolates, including 15 M. tuberculosis, one M. bovis and all 32 isolates of NTM, revealed 11 different species among the NTM isolates. The most frequent NTM isolates were M. kansasii, M. gordonae III, M. marinum, M. chelonae, M. scrofluaceum and M. gastri. In most cases, the PRA results were perfectly in accordance with the classical biochemical method. Combination of resistance to rifampin and isoniazid was present among M. kansasi, M. gordoniae III, M. scrofluaceum, M. chelonae, M. marinum, M. gastri, M. gordoniae II and M. trivale isolates. A high incidence of co-resistance to six, five, four and three anti-TB drugs was observed in 18.5%, 9.1%, 6.6% and 11.7% of all NTM isolates, respectively. Our results showed that PRA, in comparison with classical methods, is rapid and accurate enough for the identification of mycobacterial species from LJ medium. Additionally, we found that in Iran we have a highly diverse population of NTM isolates among patients suspected of having TB.

Molecular Epidemiology of Nontuberculous Mycobacteria Isolates from Clinical and Environmental Sources of a Metropolitan City

“…It has been proposed that people from Middle East region have higher susceptibility to this mycobacterium [25] . There are a few reports on virulence of M. simiae for humans in Iran [9] , [27] , [28] . Baghaei and coworkers recently described the clinical and radiological characteristics of pulmonary M. simiae infection among Iranian patients [29] .…”

“…At present, there is little data representing the incidence of NTM infections in the metropolitan cities. Limited studies showed the occurrence of NTM in respiratory samples and scant reports discussed the prevalence of NTM in an urban environment [9] – [11] . To address this lack of information, we evaluated the prevalence of environmental NTM in soil and water in four highly populated suburbs of Tehran, Iran .…”

Nontuberculous Mycobacteria Isolation from Clinical and Environmental Samples in Iran: Twenty Years of Surveillance

“…At this time, the Iranian reference laboratory provided data from 98 patients (1980–1983), of which M. fortuitum and M. kansasii were identified as the most dominant NTM in clinical samples [ 1 ]. In the following years, many researchers attempted to determine the prevalence of NTM and its importance in Iran [ 2 – 4 ]. Unfortunately, these studies failed to capture a comprehensive measure of NTM in Iran.…”

Sociodemographic, microbial and phylogentic studies of Mycobacterium tuberculosis cases diagnosed in El-Minia governorate, Egypt

“…Similarly, low transmission of M. bovis between farmers and their cattle was found, suggesting requirement of ingestion of contaminated milk from cows with tuberculous mastitis. Saifi et al (2013) reported that 80% M. tuberculosis, 6% M. bovis and 14% NTM strains were obtained from positive cultures isolates. Species identification by conventional cultural methods and biochemical tests are of limited value because of the comparatively low yield of the culture and long time to grow.…”