The present study was conducted to detect the occurrence of beta‐lactamase and biofilm‐producing Escherchia coli and Salmonella in apparently healthy broiler birds reared in household and contract poultry farms. In total, 150 cloacal swabs were collected from apparently healthy broiler birds of various age groups reared in backyard (n = 100) and contract farms (n = 50) in West Bengal (India). The isolation rate of ESBL producers was significantly more (P < 0·05) reared in contract poultry farms than those reared in backyard. Majority of the E. coli isolates possessed blaCTX‐M followed by blaSHV and blaTEM. Majority of the Salmonella strains possessed blaTEM followed by blaCTX‐M, and no blaSHV was detected. The selected sequences of the PCR products were found cognate with blaCTX‐M‐1, blaCTX‐M‐2, blaCTX‐M‐9, blaCTX‐M‐14, blaCTX‐M‐15, blaSHV‐12 and blaTEM‐52. The study detected 46·8% of E. coli and 42·5% of Salmonella strains as biofilm producers. Beta‐lactamase‐producing Enterobacteriaceae strains showed resistance against tetracycline, chloramphenicol, doxycycline, co‐trimoxazole and ampicillin and sensitivity to imipenem‐EDTA, colistin and gentamicin. The study revealed the partial clonal relationship of ESBL sequences possessed by the poultry isolates of the present study and local clinical isolates available in the database. The study made consumer awareness about careful handling of live birds or poultry meat to avoid the zoonotic transmission of antimicrobial‐resistant Enterobacteriaceae.

ObjectivesThe present study was conducted to detect the occurrence of β-lactamase and biofilm-producing Escherichia coli, Salmonella, and Klebsiella in broilers and native fowl reared in the Andaman and Nicobar Islands, India. The study also included molecular docking experiments to confirm the nature of the catalytic domains found in the β-lactamase variants obtained and to reveal the clonal relationship of the isolates with human clinical strains from the database.Materials and methodsA total of 199 cloacal swabs were collected from five poultry breeds/varieties (broiler, Vanraja, Desi, Nicobari, and layer) in three districts of the Andaman and Nicobar Islands. E. coli, Salmonella enterica, and Klebsiella pneumoniae were isolated by standard techniques and confirmed by PCR. Phenotypical β-lactamase producers were identified by a double-disc test. The genes (blaCTX, blaSHV, blaTEM, and blaAmpC) were screened, and selected sequences of β-lactamase variants were submitted to DDBJ. Homology modeling, model validation, and active site identification of different β-lactamase variants were done by the SWISS-MODEL. Molecular docking was performed to identify the catalytic domains of the β-lactamase variants. The selected β-lactamase sequences were compared with the Indian ESBL sequences from human clinical strains in NCBI-GenBank.ResultsIn total, 425 Enterobacteriaceae strains were isolated from the collected samples. Klebsiella pneumoniae (42.58%) was found to be the most prevalent, followed by Salmonella enterica (30.82%) and E. coli (26.58%). The phenotypical antibiogram of all 425 isolates showed the highest resistance against oxytetracycline (61–76%) and the lowest against gentamicin (15–20%). Phenotypical production of β-lactamase enzymes was observed in 141 (33.38%) isolates. The isolation rate of β-lactamase producing E. coli, Salmonella enterica, and Klebsiella pneumoniae was significantly higher (p &lt; 0.05) in the birds reared in the South Andaman district (25.6, 17.5, and 18.7%, respectively) than in Nicobar (11.5, 7.6, 7.1%, respectively). Genotyping of the β-lactamase-producing isolates revealed the maximum possession of blaTEM, followed by blaSHV and blaCTX − M. The nucleotide sequences were found to be similar with blaCTX − M−15, blaSHV − 11, blaSHV − 27, blaSHV − 228, blaTEM − 1, and blaAmpC in BLAST search. Distribution of studied biofilm-associated genes in Enterobacteriaceae strains from different varieties of the birds revealed that the layer birds had the maximum possession, followed by Vanraja, Desi, broilers, and Nicobari fowls. The phylogenetic analysis of selected sequences revealed a partial clonal relationship with human clinical strains of the Indian subcontinent. Molecular docking depicted the Gibbs free energy release for 10 different macromolecules (proteins) and ligand (antibiotic) complexes, ranging from −8.1 (SHV-27 + cefotaxime) to −7 (TEM-1 + cefotaxime) kcal/mol.Conclusion and relevanceThe study revealed β-lactamase variants circulating in the fowl population of the Andaman and Nicobar Islands (India), even in remote places with low anthropogenic activity. Most of the strains possessed blaTEM − 1, followed by blaCTX − M−15. Possession of blaSHV − 11, blaSHV − 27, and blaSHV − 228 in poultry Enterobacteriaceae strains was not reported earlier from any part of the world. The phylogenetic analysis revealed a partial clonal relationship of β-lactamase sequences with the human clinical strains isolated from the Indian subcontinent.

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The emergence of biogenic nanomaterials as novel antimicrobials introduces a new paradigm in human health care. Based on the recent reports of the World Health Organization, infectious diseases pose one of the greatest health challenges. Increased multi-drug resistance prevalence among human pathogens, due to the inefficiency of commercially available antimicrobial drugs in the market is a great threat to humans. The poor solubility, stability and side effects of the antibacterial therapy prompted the researchers to explore new innovative strategies for developing new antimicrobials. Recently, biogenic nanoparticles have proven their effectiveness against multidrug-resistant (MDR) pathogens as an alternative to conventional antibiotics. Biogenic nanoparticles such as silver nanoparticles (AgNPs) and Zinc Oxide nanoparticles (ZnONPs) are easy to produce, biocompatible, provide enhanced uptake and are eco-friendly. Moreover, the capping of the biogenic nanocrystals provides an active surface for interaction with biological components, facilitated by free active surface functional groups to enhance their efficacy and delivery. Inorganic nanocrystals (AgNPs and ZnONPs) are effective both as nano-bactericides and as nanocarriers against sensitive and MDR) pathogens. The present chapter focuses on the utilization of the recent nanosystems to combat drug resistance in human pathogens. Nanomedicine represents a new generation of potiential antimicrobial candidates capable of combating the drug resistance in various pathogenic organisms.