Background:Milk is considered as complete food and an important part of human diet throughout the world including India. Bacterial contamination of milk such as Escherichia coli due to unhygienic condition and poor udder health can cause infections, especially in infants and elders or in immunocompromised persons. Possession of antimicrobial resistance genes by commensal bacteria present in milk makes the issue more serious.Aim:The study was aimed to isolate and characterize extended-spectrum beta-lactamase (ESBL)-producing E. coli from milk samples collected from different parts of West Bengal, India, to assess the potential risk associated with the food.Materials and Methods:Around 182 milk samples were collected from apparently healthy cows reared by organized dairy farms in West Bengal. E. coli was isolated from collected samples as per standard methods followed by serotyping. The detection of ESBL-producing E. coli was done both phenotypically and genotypically by detecting the presence of blaCTX-M gene. Antibiogram of the ESBL-positive isolates was done using common 12 antibiotics by disc diffusion method.Results:A total of 22 (12.1%) samples were found to be positive for E. coli in this study. Different serotypes such as O11, O20, O22, O34, O35, O128, O149, and UT were isolated from the collected samples. 12 (54.5%) E. coli strains showed the capability of producing ESBL, both phenotypically and genotypically with the presence of blaCTX-M gene. Antibiogram of these ESBL-positive isolates revealed the drugs such as colistin (100%), levofloxacin (83.33%), and imipenem (66.67%) to be highly sensitive against this pathogen but drugs such as cefotaxime (100%), ceftazidime (91.67%), amoxicillin/clavulanic acid (83.33%), tetracycline (75.00%), and gentamicin (58.33%) to be very much resistant.Conclusion:More than 50% of the E. coli strains prevalent in the bovine milk samples were positive for ESBL production and are resistant to most of the common antimicrobials which may be alarming for human health.

This study was undertaken to detect the occurrence of beta‐lactamase and biofilm producing Enterobacteriaceae in healthy ducks. A total 202 cloacal swabs were collected from ducks kept in organized (n = 92) and backyard (n = 110) farms in West Bengal (India). The ducks had no history of antibiotic intake. Among the 87 phenotypically beta‐lactamase producing Escherichia coli, 19 (17·43%), 6 (5·05%) and 15 (13·76%) isolates possessed blaTEM, blaSHV and blaCTX‐M respectively. Whereas, 5 (38·46%) Salmonella isolates were found to harbour blaCTX‐M. In K. pneumoniae 10 (33·33%), 3 (13·33%), 4 (13·33%) isolates possessed blaTEM, blaSHV and blaCTX‐M respectively. The sequences of selected PCR products were found 98% cognate with blaCTX‐M‐9, blaSHV‐12 and blaTEM‐1. Beta‐lactamase producing E. coli isolates belonged to 14 different serogroups such as O1, O2, O3, O5, O7, O8, O35, O83, O84, O88, O119, O128, O145 and O157. Moreover, 87 E. coli (79·82%), six Samonella (46·15%) and 13 K. pneumoniae (43·33%) isolates were detected as AmpC producers possessing blaAmpC. Majority of E. coli (46·79%), Salmonella (46·15%) and K. pneumoniae (70%) isolates were detected as biofilm producers and possessed the associated genes (csgA, sdiA, rcsA, rpoS). Significantly higher occurrence of beta‐lactamase and biofilm producing Enterobacteriaceae isolates was detected in backyard ducks than organized farms. Significance and Impact of the Study Consumption of antibiotic through feed or during therapy is considered as potential reason for generation of antimicrobial resistant bacteria in birds. This study provides valuable evidence that exposure to contaminated environment may be an additional source for generation of antimicrobial resistant bacteria in backyard ducks. The backyard ducks are reared by marginal farmers in India who cannot offer antibiotics to them either through feed or during therapy due to high cost. The study also reveals a significant correlation between biofilm formation and possession of antimicrobial resistance genes in the bacterial isolates from the ducks.

Aim:The aim was to characterize Salmonella enterica serovar Gallinarum isolated from backyard poultry by polymerase chain reaction (PCR) detection of virulence genes invasion (invA) and Salmonella plasmid virulence C (spvC).Materials and Methods:Two strains of Salmonella serovar Gallinarum isolates used in this study were obtained from an outbreak of fowl typhoid in backyard Vanaraja fowl. PCR technique was used for detection of invA and spvC genes using standard methodology. The invA PCR product from one representative isolate was sequenced and compared with other related Salmonella serovars in GenBank data.Results:Salmonella Gallinarum produced expected amplicons of invA and spvC gene products. Nucleotide sequence of 285 bp invA gene was deposited in GenBank with accession no. KX788214. Sequence analysis of invA gene was found conserved in Salmonella serovars and demonstrated 100% homology with closely related serovars of Salmonella.Conclusion:Invasion gene (invA) was found to be highly conserved in Salmonella Gallinarum and highly similar with closely related serovars. The isolates also contained plasmid-mediated spvC gene indicating possession of virulence plasmid.

Significance and Impact of the Study: Characterization of antimicrobial resistance is an utmost necessity in animals having direct contact with human as a part of the one health approach. This is the first large-scale monitoring of ESBL/biofilm-producing Klebsiella in companion/household animals in India sharing human habitat. Majority of the Klebsiella possessed bla CTX-M-15 which is associated with infection in both humans and animals throughout the world. Few nucleotide sequences of bla CTX-M in the present study are reported for the first time from the companion animals. The emergence of resistance determinants in Klebsiella isolated from companion and household animals was correlated with therapeutic antibiotic exposure and contaminated environment, respectively.

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