PORTEEN KSANGAVIM CTANUVASSURESHKANNAN SAMUEL MASILAMONI RONALD B2024-01-112024-01-112021https://krishikosh.egranth.ac.in/handle/1/5810206141The aim of the study was to determine the occurrence of Non TuberculousMycobacteriainlivestockandfarm environment(organizedandunorganizedfarms) in and around Chennai, Tamil Nadu and to investigate the presence ofantimycobacterialresistancepatternagainst theisolatesobtainedinthestudy. A total of 218 samples, including 50 water samples, 55 milk samples, 50 soilsamples, 50 dung samples and 13 sewage samples were collected from multiplefarmpremisesin andaround Chennai andthesamplesweresubjected to isolation and identification of NTM species by conventional and molecular methods. Allthe samples were subjected todecontamination protocols using oxalic acid-NaOH and CPC. Sediments from the decontaminated samples were screenedinitially by Acid Fast Staining and the samples showing Acid Fast Bacilli were cultured in liquid mediaviz.Herrold’s eggyolk broth and Middlebrook 7H9 broth. The samplesfrom liquidmedia were streaked on MB 7H10 agar andincubated. The presumptive isolates were subjected to various biochemical testslike growth on McConkey agar, growth in 5% NaCl, catalase test, iron re-uptakemechanism from the medium and T2CH test. Further confirmation of the isolateswere done by PCR assay targeting 16SrRNA and hsp 65 genes and then the PCR products were subjected to sequencing.The isolates confirmed as NTM by genotypic characterization was subjected to AMR studies by broth microdilution method against first line antimyco bacterial drugs like rifampicin, isoniazid, ethambutol and pyrazinamide with varying concentrations starting from 100μg to 0.0048μg. The isolates were then tested for AMR by disc diffusion method using azithromycin, rifampicin, enrofloxacin, ciprofloxacin, imipenam, amikacin, doxycycline and cotrimaxazole and the sensitivity and resistance pattern were recorded.EnglishThesis