Occurrence of Non-Tuberculous Mycobacterium in clinical samples - a potential pathogen.

Background: Silent presence of non-tuberculous mycobacterium (NTM) has been observed since the last 100 years, but now the increasing incidence of NTM is of great concern for clinical microbiologists as well as clinicians. Although many advanced efforts are being made for identification and control of Mycobacterium tuberculosis, still the silently growing menace of non-tuberculous mycobacteria is receiving negligible attention. Objectives: This study was aimed to find NTMs in positive cultures and identify them up to species level. Material & Methods: During the study period, i.e. from January 2009 to June 2011, a total of 4104 positive cultures were subjected to species identification by different morphological and biochemical tests. All the tests for identification were performed as per standard procedure along with the standard strains of NTM provided by JALMA, Agra. Results: The identification of positive cultures showed 4044/15581 (25.95%) Mycobacterium tuberculosis complex and 60/15581(0.38%) NTM. The mycobacterium species identification results showed that out of total 60 NTM, 21 different species of NTM were found and they belonged to all the four groups of runyon. The most common species identified in this study was M.simiae (07) followed by M.avium(06), M.gordonae(05), M.kansasii(05), M.fortuitum(05), M.chelonae(05), M.pheli(05), M.terrae(04), M.szulgai(02), M.vaccae(02), M.flavescens(02), M. trivale(02), M.malmoense(01), M.scrofulaceum(01), M.intracellulare(01), M.xenopi(01), M.ulcerans(01), M.tusciae(01), M.triplex(01), M.septicum(01), M.mucogenicum(01). Conclusion: The isolation of NTMs from different clinical samples indicated that they may be the causative agents for pulmonary and extra-pulmonary non-tuberculous diseases. Elaborate and focused studies are needed to differentiate NTMs amongst commensal/colonizer, pathogen and laboratory contaminants.

Comparison of media and antibiotic supplements for isolation of Helicobacter pylori from gastric biopsies.

Our objective was to improve the media and the antibiotic supplements in order to increase the detection rate of Helicobacter pylori from gastric biopsy specimens. For the primary isolation of H. pylori taken from gastric biopsies, we compared the efficacy of two media: Columbia blood agar (CBA, Difco); brain heart infusion agar (BHIA, Difco); and two antibiotic supplement sets--a commercial antibiotic supplement (SR147, Oxoid) and an in-house antibiotic supplement (IHS). Gastric biopsies obtained from 210 patients were diagnosed by culture, rapid urease test (RUT) and histology. The true positive criteria were defined as a culture or both urease and histology tests being positive. The H. pylori infection rate was 44.3% (93/ 210). To compare the two media, a total of 106 gastric biopsies were plated on CBA or BHIA with 7% human blood, containing the antibiotic supplement SR147 and incubated under microaerophilic conditions. Of the 106 samples, 48 (45.3%) case of H. pylori infection, compared to the true positive criteria. The isolation rate using a combination of the two media was 83% (40/48). Of the 40 samples, 36 (90%) and 35 (87.5%) were positive on CBA and BHIA, respectively. To compare the two antibiotic supplement sets, a total of 104 gastric biopsies were plated on CBA, containing the commercial antibiotic supplement SR147 (5 mg/l trimethoprim, 10 mg/l vancomycin, 5 mg/l amphotericin B and 5 mg/l cefsulodin) or containing IHS (5 mg/l trimethoprim, 10 mg/l vancomycin, 2 mg/l amphotericin B and 2,500 U/l polymyxin B). Of the 104 samples, 45 (43.2%) case of H. pylori infection were found compared to the true positive criteria. The isolation rate using a combination of the two selective supplement sets was 82% (37/45). Of the 37 samples, 35 (95%) and 34 (92%) were positive with SR147 and IHS, respectively. Our study indicates that the combination of the two media and two antibiotic supplements is useful for maximum recovery of H. pylori isolated from gastric biopsies. CBA, and the commercial antibiotic supplement SR147 provided higher detection rates for H. pylori than BHIA, and IHS but the differences were not statistically significant.