PHENOTYPIC AND GENOTYPIC CHARACTERIZATION OF EXTENDED SPECTRUM BETA-LACTAMASE PRODUCING ESCHERICHIA COLI FROM POULTRY
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Date
2019-07
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KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR
Abstract
Extended Spectrum Beta-lactamase producing E. coli have emerged as important
food-borne pathogens. Food producing animals, especially poultry have been discussed as
an important source for transmission of ESBL producing pathogens to human being. In the
present work, samples were collected from poultry (n=515) from north-eastern Karnataka
region during the period November 2017 to April 2018 were analysed. The samples were
processed and analysed for the cultural isolation, biochemical characterization and
confirmation of E.coli by PCR. ESBL production was detected by phenotypic confirmation
test as per guidelines given by CLSI. The mPCR method for the molecular characterization
was adopted targeting major genes of ESBL E. coli viz.. blaTEM, blaCTX-M and blaSHV.
Further isolates giving positive results for blaCTX-M gene were subjected to mPCR for
investigatoin of blaCTX-M variant genes viz.. blaCTX-M-1, blaCTX-M-2, blaCTX-M-8,
blaCTX-M-9 and blaCTX-M-25. ESBL positive isolates were subjected to antimicrobial
pattern study and biofilm formation detection by tube method. Phage isolation from sewage
samples against ESBL positive isolates was attempted. The results obtained by
conventional method was compared with that of mPCR. The results of ESBL E.coli
detection by phenotypic method was 45.04% and by mPCR method 18.25%. Presence of
blaCTX-M gene variants blaCTX-M-2, blaCTX-M-8 and blaCTX-M-25 was also
detected. Antibiotic sensitivity pattern of ESBL E. coli isolate exhibited resistance
commonly used important antibiotics. Biofilm formation was revealed in 92.24 percent of
isolates. Four phages were isolated from sewage sample which were effective in killing
ESBL E.coli isolates. ESBL E. coli was found to be circulating in the poultry population
under study