Molecular Characterization of Environmental Non-Tuberculous Mycobacteria Using PCR- RFLP Analysis of 441 Bp Heat Shock Protein 65 Fragments

BACKGROUND

Non- Tuberculous Mycobacteria are environmental opportunistic pathogens that can be found in various terrestrial and aquatic habitats. There are an epidemiological links between species isolated in tap water and those isolated from patients. hsp65 gene has more variability in its sequences, compared to the some more conserved genes in NTM, for identification of mycobacteria to species level. In this study, the prevalence of NTM in Isfahan City water samples was determined using culture, biochemical tests and PCR-RFLP analyses of hsp65 gene.

METHODS

Eighty-five water samples were collected and cultured. The mycobacterial isolates were identified by conventional biochemical tests. A 441 bp fragment of hsp65 genes was amplified and digested by two restriction enzymes, BstEII and HaeII. Digested products were analyzed using polyacrilamid gel electrophoresis (PAGE).

RESULTS

25.9% of the water samples contained different species of NTM. Dominant isolates were M. fortuitum (26.7%), M. chelonae like organism (13.3%) and M. mucogenicum (13.3%). Nineteen isolates of Mycobacteria were differentiated using hsp65 genes PCR-RFLP. Three isolates could not be identified at the species level because their RFLP patterns were different from other known PCR-RFLP profiles. There were different hsp65 gene PCR-RFLP profiles produced by digestion with BstEII and HaeIII.

CONCLUSION

This study showed that PCR-RFLP of hsp65 gene in mycobacteria is more reliable method for identification of NTM at the specie level than conventional phenotypic methods (P<0.05). In comparing of RFLP patterns of this study to other investigation, some minor differences were negligible.

Prevalence of Porphyromonas gingivalis and Bacteroides forsythus in chronic periodontitis by multiplex PCR

The present research decided to study prevalence of Porphyromonas gingivalis and Bacteroides forsythus in chronic periodontitis patient by use of Multiplex PCR. The subgingival plaque samples from 61 patients suffering from chronic periodontitis with probing depth PD > or = 6 and 40 healthy controls were collected by sterile curette. In this study we used two species-specific Forward primers in combination with a single Reverse primer. These primers target variable and conserved region of 16S rRNA gene, respectively. The study included 61 patients (34 women, 27 men; 24-69 years of age; mean 43) and 40 periodontally healthy controls (22 Women, 18 men, 21-69 years in age; mean 41.35%). Porphyromonas gingivalis was detected in 51 samples (83.61%) and 16 samples (40%) of chronic periodontitis patients and healthy subjects, respectively and Bacteroides forsythus was detected in 32 samples (52.50%) of chronic periodontitis patients and was not detected in any sample from healthy persons. We set up Multiplex PCR in order to detect P. gingivalis and B. forsythus simultaneously. The present data suggest that P. gingivalis is a more important cofactor in etiology of chronic periodontitis. Further studies are needed to determine spectrum of pathogenicity of the disease and effective management of diagnosis and treatment in order to decrease the risk of periodontic complicates such as systemic infection.