SUBRAMANYAM, K.V(MAJOR)RAMANI PUSHPA, R.N.SRINIVASA RAO, TPOORNA CHARAN, B2018-08-022018-08-022018-02http://krishikosh.egranth.ac.in/handle/1/5810063109THESESABSTRACT : The research work was undertaken with an objective to isolate, identify and characterize field isolates of P. multocida from sporadic outbreaks of fowl cholera. A total of 197 samples were collected from East Godavari, West Godavari and Krishna districts of Andhra Pradesh and 15 isolates of P.multocida were obtained. All the 15 isolates were analyzed for morphological, cultural and biochemical characterstics. The antibiogram with all the 15 isolates revealed, cent per cent sensitivity to Azithromycin, Ciprofloxacin, Co-Trimoxazole, Levofloxacin, and Piperacillin- Tazobactum and these antibiotics can use for therapeutic purpose, followed by Chloramphenicol (93.7%), whereas Sulphadiazine, Tetracycline, Streptomycin, Oxacillin, Metronidazole, Cloxacillin, Cefipime-Tazobactum, Ceftriaxone-Clavulanic Acid and Ceftazidime- Tazobactum were found to be highly resistant. The analyses of antibiotic-resistant genes revealed, that all 15 isolates were positive to strA and strB genes., 8 isolates were positive for sul1, 12 isolates were positive for sul 2, 3 isolates were positive for tet B and 1 isolate was positive for tetA and catA gene. All the isolates were confirmed as P. multoicda by PCR using species-specific KMT1T7 - KMT1SP6 primers with a product size of 460 bp. The capsular typing of all the isolates using capA primers confirmed the occurrence of type A capsule with a product size of 1044 bp. A multiplex PCR using species-specific and capA primers was perfomed. The virulence genes profiling was carried out for hgbA, hgbB, ompH, ptfA and pfhA genes. Each of the 15 isolates was positive for hgbA, ptfA and ompH genes, the other virulent genes such as hgbA and pfhA accounts for about 60% of the total isolates. The outer membrane proteins were extracted by the sarcosyl method and analyzed by SDS-PAGE. Out. Out of 4 protein bands, a major protein of 38 kDa was observed.ennullThesis