The present study provides first time the comprehensive molecular and phenotypic characterization of antimicrobial-resistant, biofilm-forming, and virulent Salmonella spp. isolated from apparently healthy ducks and their environments in West Bengal, India. A total of 462 samples from Indigenous, Khaki Campbell, and Pekin ducks yielded 436 isolates, of which 42.2% were ESBL producers carrying blaTEM (36.5%), blaCTX−M(20.6%), blaSHV (17.7%), and blaAmpC (32.6%). Sequence analysis revealed multiple clinically relevant alleles, including blaTEM-164, blaCTX−M-15, and blaSHV-45, underscoring their potential public health significance. The isolates were also screened for biofilm genes (csgA, sdiA, rpoS, rcsA), and the virulence gene invA. Biofilm-associated genes were widely distributed (csgA: 54.59%, sdiA: 52.52%, rpoS: 80.28%, rcsA: 63.76%), while 141 (32.34%) of isolates possessed the invA virulence marker. Of 26 selected strains, high multi-drug resistance was detected, mainly against tetracycline and cefixime. Phylogenetic analysis of ESBL gene sequences showed clustering across avian, animal, and clinical (human) Salmonella isolates, indicating potential interspecies transmission and evolutionary divergence. Notably, strong positive correlations were observed among biofilm formation, multidrug resistance, and virulence (τ = 0.656, ρ = 0.765, p < 0.001). Western blotting further identified two unique polypeptide markers (69 and 35 kDa) with diagnostic potential for detecting resistant, virulent, and biofilm-forming Salmonella. In short, these findings highlight, for the first time, duck as silent reservoirs of high-risk Salmonella strains, and propose novel protein markers to facilitate early detection at the human-animal-environment interface.

This study investigated the antimicrobial resistance (AMR) profile of Salmonella enterica (n = 446) of poultry origin (n = 1020) collected from West Bengal, India. Salmonella Typhimurium (n = 328) were the most frequently isolated serovar and found resistant to tetracycline (72

This study evaluated the effects of dietary supplementation with a Lactobacillus DH42-based probiotic and its corresponding postbiotic on growth performance, carcass characteristics, blood biochemical indices, and gut health in Rainbow Rooster chickens. A total of 160 one-day-old mixed-sex chicks were randomly allocated to four dietary treatments, with five replicates of eight birds each (n = 8). The treatment groups included (1) a basal diet without growth promoters (CON), (2) a basal diet supplemented with enramycin (80 g/ton feed; AGP), (3) a basal diet supplemented with the Lactobacillus DH42 probiotic (PRO), and (4) a basal diet supplemented with the inactivated Lactobacillus DH42 postbiotic (POS). Growth performance was recorded weekly, while carcass characteristics, serum biochemical parameters, caecal microbiota, and intestinal morphology were evaluated on day 42. Average daily gain, carcass characteristics, and meat quality were not significantly affected by the dietary treatments (P > 0.05). However, birds receiving probiotic or postbiotic supplementation exhibited lower average daily feed intake during the finisher phase (22–42 d) and the overall experimental period (1–42 d), resulting in an improved feed conversion ratio compared with the CON and AGP groups (P < 0.05). Serum cholesterol concentration was significantly reduced in the PRO and POS groups relative to the CON group (P < 0.05). Probiotic supplementation significantly reduced caecal Salmonella counts compared with the CON and AGP groups (P < 0.05), whereas Escherichia coli and Lactobacillus populations remained unaffected. Postbiotic supplementation increased villus height in the jejunum and ileum, while both probiotic and postbiotic supplementation increased the villus height-to-crypt depth ratio in the duodenum (P < 0.05). These findings indicate that Lactobacillus DH42-derived probiotic and postbiotic supplementation improved feed efficiency and intestinal health without compromising growth performance, highlighting their potential as sustainable alternatives to antibiotic growth promoters in Rainbow Rooster chickens.

Staphylococci are important mastitis pathogens in dairy animals and serve as reservoirs of antimicrobial resistance genes (ARGs) having zoonotic potential. Genomic characterization of resistant isolates is essential to understand their diversity, resistance mechanisms, and One Health implications. A total of 363 cow and buffalo milk samples—including 108 from animals with mastitis—were screened, yielding 98 staphylococcal isolates, comprising 20 Staphylococcus aureus and 78 coagulase-negative staphylococci (CoNS). Antimicrobial susceptibility testing revealed resistance to cefoxitin (CoNS: 21.7

Background: Antimicrobial resistance (AMR) is a global concern for human and animal health. As the development and commercialization of a new class of antibiotics are difficult, time-consuming and extremely costly, exploration of alternatives like bacteriophages is considered one of the most suitable sources. There is a paucity of databases on the isolation of bacteriophages and exploration of their antibacterial properties against pathogenic MDR E. coli. The current study was undertaken to isolate and identify the bacteriophages from sewages to evaluate their lytic activity against MDR pathogenic Escherichia coli isolated from domestic animals in Mizoram. Methods: Total 50 samples were collected to process for isolation, identification and characterization of bacteriophages. Simultaneously, a total of 192 rectal swabs from pigs were collected, followed by isolation and identification of Escherichia coli. All the isolates were subjected to detection of selected virulence genes by PCR and determination of their antimicrobial sensitivity profile using commercial disks. All the bacteriophage isolates were assessed for their lytic effect against the MDR pathogenic E. coli isolates. Result: A total of six bacteriophages were isolated. Transmission electron microscopy revealed that bacteriophages belong to the Myoviridae family. Total 163 E. coli was isolated, out of which 59 isolates were pathogenic, which could be classified under STEC, EPEC, EHEC and ETEC pathotypes. By disk diffusion assay, majority of the E. coli showed resistance against commonly used antibacterial agents, viz., ampicillin, ciprofloxacin, cefpodoxime, ceftriaxone, nalidixic acid, tetracycline, doxycycline, gentamicin and streptomycin. Except one, all the bacteriophages exhibited lytic activity against pathogenic and MDR E. coli field isolates. Bacteriophages isolated and identified from sewages of Mizoram exhibited antimicrobial activities against field isolates of multidrug-resistant pathogenic E. coli isolated from pigs. Bacteriophages can be considered as a potential alternative to antibiotics to control the menace of AMR.

This study was conducted to detect the occurrence and phenotypic resistance pattern of extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in livestock using docking-based analysis to reveal the classes of antibiotics against which ESBL-producers are active. Rectal swabs from healthy cattle (n = 100), goats (n = 88), and pigs (n = 66) were collected from backyard farms in Andaman and Nicobar Island (India). In total, 304 isolates comprising Escherichia coli (131), Salmonella (75), and Klebsiella pneumoniae (98) were recovered. The phenotypic resistance pattern showed that the highest resistance was found against erythromycin, followed by ampicillin/cloxacillin, ciprofloxacin, amoxicillin/clavulanic acid, and oxytetracycline. Screening of the isolates demonstrated maximum presence of blaTEM-Type, followed by blaCTX-M-Type, and blaSHV-Type. Sequence homology revealed the presence of CTX-M-15, SHV-228, SHV-40, and TEM-82. The possible interactions of CTX-M-15 with cephalosporins and SHV with carbapenems have been identified by docking analysis. The study revealed the occurrence of ESBL-producers with circulating emerging ESBL variants like SHV-40, along with the common variants with clinical relevance (CTX-M-15, TEM-82), highlighting the potential role of livestock as reservoirs for antimicrobial resistance genes. Identifying these ESBLs in livestock is crucial for understanding their contribution to the dissemination of antimicrobial resistant bacteria into the human food chain.

This study aimed to evaluate the impact of dietary supplementation with a synbiotic (Lactobacillus rhamnosus NCDC 298 + fructooligosaccharide) on the growth performance, carcass traits, blood biochemical profile, gut microbiome, gut morphology, and immune response of broiler chickens. A total of 162 day-old Ven Cobb 400 broiler chicks were randomly assigned to three dietary groups, each with six replicated pens (n = 6), containing nine broiler chickens: 1) basal diet without any growth promoter (CON), 2) basal diet with antibiotic (Bacitracin methylene disalicylate - BMD) at 500g/ton feed (AGP), and 3) basal diet with synbiotic (Lactobacillus rhamnosus NCDC 298 + fructooligosaccharide) at 1 ml/bird in drinking water (SYN). Body weight, feed intake, and feed conversion ratios (FCR) were monitored weekly for 42 days. Blood biochemistry was evaluated on day 28, and immune response was assessed on day 28 and 35 of the trial. Carcass traits, gut microbiome, and gut morphology were evaluated at the end of the trial. The results indicated that the SYN group had significantly higher final body weight and average daily gain compared to the CON and AGP groups (P<0.05). Moreover, the SYN and AGP supplemented groups showed improved FCR compared to the CON group (P<0.05). However, there were no significant differences in average daily feed intake (ADFI), carcass traits, blood biochemical profile, and antibody titers among the groups. Total E. coli and Salmonella counts were significantly lower in the SYN group compared to CON and AGP (P<0.05). Additionally, Lactobacillus counts were significantly higher in the SYN group compared to CON and AGP (P<0.05). Gut morphology was significantly improved in the SYN group compared to CON and AGP (P<0.05). In conclusion, synbiotic supplementation could be a promising alternative to antimicrobials in broiler production, demonstrating beneficial effects in broilers fed an antibiotic-free diet.

Chicken meat (broiler) production is a rapidly growing livestock sector in India, and one dominated by contract farming. Studies have reported high levels of antibiotic use in Indian broiler farms which is concerning given this is one of the driving forces for the development of antibiotic resistance. This study used the economic lens of agency theory to examine strategic decisions which occur during contract broiler production and their potential impact on antibiotic use, using West Bengal as a case study. Agency theory focuses on the informational asymmetry and opportunism between service providers and seekers and the subsequent agency cost needed to avoid aberrant outcomes. Interviews were conducted with key informants (n = 6) and stakeholders (n = 20) associated with broiler production, and broiler farmers (17 contract and four non-contract), using online and face-to-face interviews. Data were analysed descriptively using manifest content analysis and interpretatively using reflexive thematic analysis. Contract farming in West Bengal exists within a series of inter-dependent relationships, many of which contain information asymmetry and can be subject to opportunism. Positioning contract companies as principals seeking labour from agents, we see how out-sourcing of production to distal farms led to antibiotics being used as a risk mitigation strategy. This was further compounded by concerns about the Mycoplasma status of breeding stock, and a perception that broiler day old chicks were infected, resulting in use of antibiotics belonging to classes deemed critically important for human health. While antibiotic use decisions were predominately made by contract companies, they were dependent on the decisions farmers and breeding companies made concerning biosecurity and production practices. In turn, farmers’ decisions were shaped by factors such as access to financial and social capital. Thus, efforts to reduce antibiotic use in West Bengal’s broilers must not just focus on changing the prescribing behavior of individuals but more broadly consider the environment within which contracting exists.

Antibiotics remain key tools for maintaining human health, and in many settings, food production. However, emergence of antibiotic resistance has become a global challenge, one that has resulted in multi-national calls for policy to improve antibiotic use. One such call has been to restrict the use of antibiotics deemed critically important for human health, such as colistin, during the production of food producing animals. Between 2016 and 2019 numerous countries, including India, implemented policies to heavily restricted the use of colistin in livestock. While this represents a key shift in the antibiotic policy landscape, other classes of critically important antibiotics continue to be used during food production. This paper provides a policy analysis of India's 2019 colistin ban to provide insight into how this came to be and to identify factors which could shape the development of future legislation. The analysis revealed that while antibiotic reform in food production had been in the background of India's policy agenda for some time, it took key-focusing events to shift the policy climate into a period of action. These focusing events included reporting of mobile colistin resistance genes in bacteria isolated from pigs in China and colistin resistant bacteria isolated from food samples in India. Consistent narratives had been built around colistin's role as a last resort antibiotic which, together with relatively low proportion of colistin resistance in bacteria isolated from human patients, framed legislation as a worthwhile endeavour for policy makers. In addition, India acted as a global player in antibiotic stewardship and followed the precedent set by several other countries in restricting colistin use during food production. As most colistin for animal use was imported into India from China, and viable alternative animal treatments existed, there was limited industry opposition that could block legislation. We suggest evaluation of these five critical factors (focusing events, consistent narratives, worthwhile endeavour, precedent for change, and industry opposition) should be part of the policy formulation process for legislation regarding the use of other critically important antibiotics in food production.

The study was conducted to assess the effects of a postbiotic, Saccharomyces cerevisiae fermentation product (SCFP) and a commercial phytogenic feed additive (PFA) as alternative to antibiotic growth promoter(AGP) on growth performance, gut microbiota, intestinal morphology, and immune response of commercial broiler chickens at a Food and Agriculture Organization (FAO) classified sector 3 commercial poultry farm. One-day-old mixed sex Vencobb 430 Y chicks (n=4800) were randomly divided into four dietary treatment groups for 35 days experimentation encompassingT1 (positive control, PC) basal diet supplemented with bacitracin methylene disalicylate as an AGP at 500 g/MT; T2 (negative control, NC) basal diet without a growth promoter; T3 basal diet supplemented with commercial PFA at 500 g/MT; T4 basal diet supplemented with SCFP at 1.25 kg/MT.At day 35, ADG and FCR were significantly improved in PFA and SCFP groups compared to the NC group. The levels of blood glucose, total protein, albumin, triglyceride, cholesterol, and uric acid in serum showed no significant variation across different dietary treatments. From day 21 of the study, log cfu count and DNA concentration of pathogens (Enterohaemorrhagic Escherichia coli, Salmonella) decreased significantly in the AGP, PFA, and SCFP groups compared to the NC group. Whereas the log cfu count and average DNA concentration of Lactobacillus was significantly increased in PFA and SCFP groups, but not in AGP group. Increased Lactobacillus concentration in PFA and SCFP groups downregulated the virulence gene expression of pathogens (Enterohaemorrhagic E. coli and Salmonella). The duodenal and jejunal villi height was significantly higher in PFA and SCFP groups, although ratio of villi height to crypt depth in the duodenum, jejunum and ileum did not show significant differences among the groups. On day 28, antibody titers against the IBDV and NDV were significantly higher in SCFP groups than other groups. The present study did not identify any modulation of the cell mediated immune response in the chickens. In conclusion, addition of SCFP at 1.25 kg/MT or PFA at 500 g/MT in diet could produce better nutrient utilization ability, reduction of pathogens and their virulence gene expression, increased Lactobacillus count, but incorporation of SCFP increased antibody titre against two fatal viral infections such as NDV and IBDV which was not detected with PFA.

Background/Objectives: Antimicrobial resistance (AMR) is a growing global health challenge, driven in part by how antibiotics are accessed, distributed, and used within complex value chains. In peri-urban India, these supply chains involve a range of formal and informal actors and practices, making them a critical yet underexamined focus for antimicrobial stewardship efforts. While much research has focused on the manufacturing and regulatory end, less is known about how antibiotics reach consumers in rural and peri-urban settings. This study aimed to map the human antibiotic value chain in West Bengal, India, and to analyse how formal and informal governance structures influence antibiotic use and stewardship. Methods: This qualitative study was conducted in two Gram Panchayats in South 24 Parganas district, West Bengal, India. Semi-structured interviews were carried out with 31 key informants, including informal providers, medical representatives, wholesalers, pharmacists, and regulators. Interviews explored the structure of the antibiotic value chain, actor relationships, and regulatory mechanisms. Data were analysed thematically using a value chain governance framework and NVivo 12 for coding. Results: The antibiotic value chain in rural West Bengal is highly fragmented and governed by overlapping formal and informal rules. Multiple actors-many holding dual or unofficial roles-operate across four to five tiers of distribution. Informal providers play a central role in both prescription and dispensing, often without legal licences but with strong community trust. Informal norms, credit systems, and market incentives shape prescribing behaviour, while formal regulatory enforcement is inconsistent or absent. Conclusions: Efforts to promote antibiotic stewardship must move beyond binary formal-informal distinctions and target governance structures across the entire value chain. Greater attention should be paid to actors higher up the chain, including wholesalers and pharmaceutical marketing networks, to improve stewardship and access simultaneously. This study highlights how fragmented governance structures, overlapping actor roles, and uneven regulation within antibiotic value chains create critical gaps that must be addressed to design effective antimicrobial stewardship strategies.

The experiment was conducted during the month of June–July 2025 at the Department of Animal Nutrition, WBUAFS, Kolkata, West Bengal, to study the effect of postbiotics on broiler chicken performance. This study aimed to assess the impact of dietary supplementation with a postbiotic (inactivated Lactobacillus rhamnosus NCDC 298) on the performance of broiler chickens. A total of 162 day-old broiler chicks were randomly assigned to three dietary groups: 1) basal diet (CON), 2) basal diet with antibiotic (Bacitracin methylene disalicylate-BMD) at 500 gton-1 feed (AGP), and 3) basal diet with postbiotic at 1 ml/bird in drinking water (POS). Body weight, feed intake, and feed conversion ratios (FCR) were monitored weekly for 42 days. Blood biochemistry and immune response were assessed ondays 28 and 35 of the trial. Carcass traits, gut microbiome, and gut morphology were evaluated at the end of the trial.The results showed that the postbiotic supplementation (POS) significantly improved FCR compared to the CON and AGP groups (p<0.05). Antibody titers for infectious bursal disease virus (IBDV) and Newcastle disease virus (NDV) did not differ significantly among the groups, except for a higher NDV titer on day 28 in the POS group compared to CON and AGP (p<0.05). Total E. coli counts were significantly lower in the POS group compared to CON and AGP (p<0.05), while total Salmonella counts were lower in the POS group compared to CON (p<0.05). In conclusion, postbiotic supplementation shows promise as an alternative to antimicrobials in broiler production.

Investigating innate immunity and its signaling transduction is essential to understand inflammation and host defence mechanisms. Toll-like receptors (TLRs), an evolutionarily ancient group of pattern recognition receptors, are crucial for detecting microbial components and initiating immune responses. This review summarizes the mechanisms and outcomes of TLR-mediated signaling, focusing on motifs shared with other immunological pathways, which enhances our understanding of the innate immune system. TLRs recognize molecular patterns in microbial invaders, activate innate immunity and promote antigen-specific adaptive immunity, and each of them triggers unique downstream signaling patterns. Recent advances have highlighted the importance of supramolecular organizing centers (SMOCs) in TLR signaling, ensuring precise cellular responses and pathogen detection. Furthermore, this review illuminates how TLR pathways coordinate metabolism and gene regulation, contributing to adaptive immunity and providing novel insights for next-generation therapeutic strategies. Ongoing studies hold promise for novel treatments against infectious diseases, autoimmune conditions, and cancers.