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20212
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Subject: Veterinary Microbiology × End date: 2021 × Start date: 2020 ×
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    ThesisItemOpen Access
    ISOLATION AND CHARACTERIZATION OF CAMPYLOBACTER IN POULTRY
    (KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR, 2021) SAHITHYA, N.G.; D. RATHNAMMA
    The present study was conducted to isolate and characterize Campylobacters from poultry. A total of 158 poultry samples were collected from RMS, CPF and BYPF from different districts. All the samples were subjected for pre-enrichment followed by selective isolation of Campylobacters on mCCDA and Columbia blood agar. Seventyfive (47.46%) Campylobacter isolates were obtained and further confirmed by PCR. Genus specific PCR was standardised to identify Campylobacter isolates at genus level by amplifying 16S rRNA gene. Further species level identification was done by amplifying lpxA gene where 52 isolates were identified as C.jejuniand seven as C.coli. Remaining 16 isolates were unidentified campylobacter species. The prevalence of C.jejuni was more (76%) compared to C.coli (9.33%). Antibiotic sensitivity of all 75 Campylobacter isolates was tested by standard Kirby-Bauer disc diffusion method. All Campylobacter isolates showed 100 per cent resistance to Clindamycin and Nalidixic acid, followed by Erythromycin (73.33 %), Tetracycline (61.33%), Azithromycin and Doxycline (53.33%) and Ampicillin and Amoxicillin/Clavulanic acid (44%). The presence of AMR genes in 52 C.jejuni isolates was carried out by PCR. Where all 52 isolates (100%) showed amplification of 23S rRNAgene for Macrolides followed by Fluoroquinolone (86.54%) by Amplifying QRDR region of gyrA gene, Tetracycline (53.84%) by amplifying tet (O) gene, 50 per cent isolates showed amplification of blaOXA-61 gene for Beta-lactams and 69.23 per cent isolates were found to harbour cmeB efflux pump gene. Amplification of cad-F and flaA virulent genes was carried out by subjecting 52C.jejuni isolates to PCR, all the C.jejuni isolates revealed cad-F gene and 29C.jejuni isolates revealed flaA gene . Partial nucleotide sequencing of cad-F gene was done for 12 campylobacter isolates. The phylogenetic analysis revealed two groups where farm isolates formed one group and isolates from retail meat shops formed another group. The highest mean interspecific divergence was found between LH and K2 (10.42%) and it was lowest between TF and BBY (0.02%). Genotyping of 50 C.jejuni isolates was carried out by ERIC-PCR and intra-species variability of C. jejuni isolates was determined by dendrogram analysis of C. jejuni that revealed 12 distinct clades with discriminatory power (D value) of 0.87. Campylobacter jejuni isolates under study formed two main clusters (A and B) with 100% heterogeneity.
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    ThesisItemOpen Access
    STUDIES ON AEROBIC BACTERIA ISOLATED FROM BOVINE SUBCLINICAL AND CLINICAL ENDOMETRITIS
    (KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR, 2021) PAVITHRA B.S.; B.E. SHAMBULINGAPPA
    Bacterial endometritis results in lower and delayed conception rates in affected cows. The present study was conducted to isolate and characterize aerobic bacteria from subclinical (SE) (n=82) and clinical endometritis (CE) (n=51) cases in cows. In addition, studies on antibiogram profile, MIC and major virulence genes were also carried out. Fifty eight of 82 uterine lavage samples showing 1-5% of PMN cells by endometrial cytology were considered as subclinical endometritis cases. Bacterial isolation and phenotypic characterization of the isolates revealed E. coli, S. aureus, S. uberis, P. aeroginosa, P. mirabilis, K. pneumoniae and B. cereus from SE and in addition to these, R. equi and C. bovis were also recovered in CE cases. PCR was used to confirm the bacterial species targeting uspA and uidA genes in E. coli and nuc gene in S. aureus. Major virulence genes in E. coli viz., fimH, fyuA, kpsMTII, csgA were detected by PCR in 100%, 47.82%, 17.39%, 26.08% of the SE isolates, and in100%, 73.07%, 38.46%, 34.61% of CE isolates respectively. Spa gene was detected in all S. aureus isolates and the spa type was t359. The antibiogram study by disc diffusion method using most commonly used 19 antibacterials revealed that most of the isolates were susceptible to ciprofloxacin, enrofloxacin, gentamicin and ceftriaxone, and resistant to penicillin and polymyxin B. MIC values for ceftiofur, ciprofloxacin and gentamicin were within the susceptibility range for most of the isolates. Out of 36 S. aureus isolates, phenotypic methicillin resistance was detected in two whereas mecA gene was detected only in one isolate by PCR. The study gives an insight into the etiological profile, antibiogram, virulence potential of the bacterial agents associated with bovine endometritis. Key words: Endometritis, aerobic bacteria, virulence genes, antimicrobial susceptibility, minimum inhibitory concentration