Out of 197 samples, a total of 134(68.02%)
Escherichia coli and 33(16.75%)
Klebsiella pneumoniae were detected from the cloacal and environmental samples of the duck. The study showed a higher prevalence of
E.
coli (72.09%) and
Klebsiella pneumoniae (20.93%) in environmental samples
(Nnachi et al., 2015). In Nigeria, a similar investigation by
Adzitey et al., (2012) revealed 70.83%
E.
coli isolates from soil, confirming the present findings.
Bariha et al., (2019) from India, reported 55% positivity of
E.
coli from different duck samples from ducks. Again
Banerjee et al., (2019) found 53.96%
E.
coli and 14.80%
K.
pneumoniae from faecal samples of ducks in West Bengal, which were lower than the current findings. Both were gram-negative bacilli and typical in biochemical characterization
(Quinn et al., 1994).
All 134 nos. tentatively positive
E.
coli isolates were having the 16S
rRNA gene (585 bp) specific for
E.
coli (Fig 1). Around 33 isolates were confirmed to be
Klebsiella pneumoniae with 130 bp amplified product in PCR (Fig 2). A total of 12 different serogroups were found such as O98, O157, O135, O120, O63, O26, O121, O101, O8, O118, O119 and O22 among which, O120 was the most prevalent one, in serogrouping of
E.
coli isolates
(Banerjee et al., 2019; Wang et al., 2010).
Out of 134, 107 (79.85%)
Escherichia coli isolates (Fig 3) and out of 33, 24 (72.73%)
Klebsiella pneumoniae isolates (Fig 4) were detected as phenotypical ESBL/ACBL producers based on double-disc synergy assays. During molecular detection of the resistance genes, a total of 36(26.86%)
E.
coli and 6(18.18%)
K.
pneumoniae isolates were found to possess the
blaCTX-M gene (540bp) with other genes (
blaTEM and
blaSHV) too (Table 1). The presence of the
blaAmpC gene (634 bp) was quite high in both bacteria.
Nalband et al., (2020), Ma et al., (2012) also reported much higher prevalence of ESBL genes in
E.
coli which is almost similar to the present study. The findings of
Banerjee et al., (2019), Raza et al., (2017) also match this report and thus stand confirmed.
A total of 23 (17.16%)
Escherichia coli isolates were found to be positive for different virulence genes viz.
stx1 (180bp),
stx2 (255bp),
eaeA (384bp) and
hlyA (534bp) in the multiplex PCR assay (Table 2, Fig 5).
Majumder et al., (2017) and
Banerjee and Acharyya (2020) reported approx. 20-24% STEC producing
E.
coli from cloacal samples of duck which was higher than the present findings.
No
Klebsiella pneumoniae isolate was found positive for the
rmpA gene (535bp) in this study.
Yang et al., (2019) reported a very less (10.6%) prevalence of the
rmpA gene in human origin
Klebsiella pneumoniae. Animal origin
Klebsiella spp. may possess this gene
(Younis et al., 2016) but the present variation might be due to variation in geographical variances.
Around 67.91%
Escherichia coli and 78.79%
Klebsiella pneumoniae isolates were found to possess at least one of these biofilm-producing genes
viz.
rpoS (120 bp),
csgA (178 bp),
sdiA (239 bp) and
rcsA (306 bp) (Table 3). Approx. 27
E.
coli and 13
K.
pneumoniae isolates were found to possess more than one biofilm-producing gene in this study which was also supported by
Bakhtiari and Javadmakoei (2017) and
Banerjee and Acharyya (2020).
This study showed that 30.43% ESBL-
E.
coli and 47.82% biofilm-producing
E.
coli to possess virulence genes, but 56 ESBL-
E.
coli were positive for biofilm production too. Again only 02 isolates were positive for the ESBL, Biofilm producing and virulence genes as revealed in this study. This reveals a significant relationship were also reported by Jegadeesh
Kumar et al., (2016) and
Fattahi et al., (2015), which confirms these present findings too.
All the ESBL and biofilm-producing
E.
coli isolates were resistant to ampicillin and approx. 61-86% resistant to norfloxacin, ertapenem, ciprofloxacin, tetracycline and ceftazidime respectively (Table 4).
Na et al., (2019) also reported resistance to tetracycline (59.3%) and other drugs of
E.
coli in their study.
A total of 95.24% of all ESBL and biofilm-producing
K.
pneumoniae isolates (n=21) were resistant to ampicillin followed by 85.71%, 85.71%, 80.95%, 76.19%, 57.14% and 52.38% resistant to cefotaxime, ticarcillin/ clavulanic acid, ertapenem, ceftazidime, norfloxacin and ciprofloxacin respectively. Sensitivity was detected against chloramphenicol, co-trimoxazole and gentamicin (@61-92%) [Table 5]. Almost similar reports were shown by
Nnachi et al., (2015) and
Kumar et al., (2022), thus the current result stands confirmed.