Detection and Characterization of b-lactamases and Biofilm-producing Escherichia coli and Klebsiella pneumoniae from Ducks and Duck Environments in West Bengal

Background: Escherichia coli and Klebsiella pneumoniae are two important commensals with pathogenic potentiality in animals and birds, causing intestinal and extra-intestinal infections. These are somewhat zoonotic too via different routes. So, the present study was undertaken to investigate the prevalence of these two bacteria from cloaca and environment of ducks from different districts of West Bengal, followed by detailed characterization and antibiogram. Methods: Around 197 duck and environmental samples were collected from different districts of West Bengal. E. coli and K. pneumoniae were isolated from collected samples as per standard methods followed by serotyping of the E. coli isolates. The detection of ESBL/ACBL producing isolates was done both phenotypically and genotypically by detecting the presence of antibiotic-resistant genes. Virulence property and biofilm-producing ability of these isolates were also studied. Antibiogram of the ESBL and biofilm positive isolates were done using common 12 antibiotics by disc diffusion method. Result: A total of 134(68.02%) Escherichia coli and 33(16.75%) Klebsiella pneumoniae isolates were recovered and confirmed by PCR. The prevalence of E. coli and K. pneumoniae in cloacal swabs were less in comparison to the environmental samples (72.09% and 20.93%). Approx. 79.85% E. coli and 72.73% K. pneumoniae isolates were found to be the ESBL/ACBL producers in vitro. E. coli and K. pneumoniae isolates possessed all major antibiotic-resistant genes with the blaAmpC (64.18% and 48.48%) being the most prevalent one. Twenty three (17.16%) E. coli isolates were found positive for the virulence genes, of which stx1 (39.13%) was the most common one as detected by multiplex PCR. No virulence gene was found in K. pneumoniae isolates. Ninety one (67.91%) E. coli and 26(78.79%) K. pneumoniae isolates possessed the biofilm-producing genes. All the ESBL and biofilms producing E. coli and K. pneumoniae isolates showed 100% - 95.24% resistance to ampicillin. A high percentage of resistances were also seen against cefotaxime, ticarcillin/ clavulanic acid, ertapenem, ceftazidime, norfloxacin and ciprofloxacin, which may be due to several reasons. Maximum overall sensitivity was detected against chloramphenicol, co-trimoxazole and gentamicin.