In present study, total 240 samples comprising 160 normal and 80 diarrhoeic faecal samples were processed for isolation and confirmation of
E. coli and
Klebsiella spp. The presumptive positive isolates of
E. coli and
Klebsiella spp. on the basis of their morphology, growth, cultural and biochemical characteristics were found 91.25% and 26.25% respectively (Table 3). Further PCR analysis revealed total 90.80% confirmed isolates comprising 71.67%
E. coli and 19.16%
Klebsiella spp. (Fig 3, 4 and Table 3). Similar findings have been also reported by
Yadav et al., (2024) and
Gupta et al., (2019). The isolation rate of
E. coli was found much higher than
Klebsiella spp. in both cattle and buffaloes which may be attributed to high prevalence of
E. coli in GIT of ruminants as compared to other members of family
Enterobacteriaceae.
The present study also aimed to detect the occurrence of carbapenemase producing isolates among the clinical and apparently healthy animal isolates. Total 218 isolates (172
E. coli and 46
Klebsiella spp.) were subjected to screening and confirmatory phenotypic tests. Out of 218 confirmed isolates, 21.55% (47/218), 16.51% (36/218) and 12.84% (28/218) presumed as carbapenemase producer by screening test, DDST and MBL-E strip test respectively (Table 4). There was little difference in the sensitivity of both phenotypic confirmatory test used for detection of carbapenemase producers and this observation corroborated with the findings of
Bora et al., (2014) and
Yadav et al., (2021). Phenotypic confirmatory method revealed the occurrence of 8.75% (3.75%
E. coli and 5.0%
Klebsiella spp.) in normal faecal 12.5% (7.50%
E. coli and 5.0%
Klebsiella spp.) in diarrhoeic faecal, 11.25% (5.0%
E. coli and 6.25%
Klebsiella spp.) in normal faecal and 17.50% (7.50%
E. coli and 10.0%
Klebsiella spp) in diarrhoeic faecal samples of cattle and buffaloes respectively (Table 5). Similar to our finding, low percentage of carbapenemase positive
E. coli has also been reported by
Braun et al., (2016), Webb et al., (2016), Nirupama et al., (2018) from faecal samples of different spp. and Yadav
et al. (2021) from milk samples of bovine. However some of the workers have reported higher occurrence of carbapenemase producers among faecal samples ranging from 21.64% to 29.03% from various parts of India
(Gupta et al., 2019; Murugan et al., 2019; Pruthvishree et al., 2017). These differences in the findings of various co-workers may be attributed to variations in source and animal husbandry practices in geographical locations.
Confirmation of carbapenemase producing isolates was done by PCR analysis by targeting
bla-
NDM,
bla-
KPC and
bla-
OXA-48genes (Fig 5, 6, 7), which revealed 17/218 (7.80%) carbapenemase positive isolates comprising 7/172(4.07%)
E. coli and 10/46(31.25%)
Klebsiella spp. (Table 6). The overall gene distribution study showed 30.77% occurrence of
bla-
NDM and 23.07%
bla-
KPC in
E. coli isolates while 53.33% of
bla-
KPC and 13.33%
bla-
OXA-48 genes in
Klebsiella spp. It was notable under this study that
bla-
KPC gene was reported both in
E. coli and
Klebsiella spp where as
bla-
NDM was only reported in
E. coli and
bla-
OXA-48 only in
Klebsiella spp. (table-6). The occurrence of
bla-
OXA-48 was found very low but it is very significant from public health point of view, as it is increasingly being reported from nosocomial infections in which
Klebsiella spp. is most commonly implicated and in best of my knowledge, this is the first report of
bla-
KPC and
bla-
OXA-48 gene detection in faecal samples of bovine in India. Similar to our finding these carbapenemase genes have been also reported from various parts of India and abroad in previous studies like
bla-
NDM-1 and
bla-
OXA-48 genes in piglets
(Pruthvishree et al., 2017; Nirupama et al., 2018), bla-
VIM in calves
(Murugan et al., 2019), bla-
OXA-48 in cattle faeces
(Braun et al., 2016) and in milk (
Diab et al., 2017;
Yadav et al., 2021). The occurrence of such genes in faecal samples of bovine is of great significant as can be transferred to human and animal horizontally through contaminated food, water and environment leading to various food-borne diseases.
Nowadays antimicrobial resistance is of great concern globally and a matter of serious threat to humanity which has received the attention of policy makers along with scientific community. In present study all
E. coli and
Klebsiella spp. isolates were 100% sensitive to aminogycosides, polypeptides and chloramphenicol whereas 84.61% to 100% resistant against carbapenems, 3
rd and 4
th generation cephalosporines, monobactams and penicillin group of antibiotics (Table 7). Both
E. coli and
Klebsiella spp. isolates showed resistance 26.67% to 80.0% against non-β-lactam group of antibiotics. There are several evidences that corroborate with these findings in India and abroad for both
E. coli and
Klebsiella spp. isolated from bovine
(Gupta et al., 2019; Ibrahim et al., 2018; Yadav et al., 2022). The plausible factors showing extreme level of resistance to several groups of antibiotic may be due to irrational and over use of these antibiotics without performing antibiotic sensitivity testing for treatment and in feed additives.
@table7
