ISOLATION AND CHARACTERIZATION OF CAMPYLOBACTER IN POULTRY
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Date
2021
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KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR
Abstract
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.