Drug-Resistant Bacteria Found Circulating Through India’s Poultry Supply Chain

A sweeping surveillance study across India’s western state of Gujarat has uncovered a troubling picture of foodborne pathogens and antimicrobial resistance circulating through the poultry industry, one of the largest in the world. Researchers sampled 65 live bird market shops and 50 poultry farms in eight cities, recovering Campylobacter from roughly 10 percent of birds and Escherichia coli from more than half. More alarmingly, many of the isolated bacteria were not merely resistant to one or two drugs: substantial fractions qualified as extensively drug-resistant, and a smaller but significant number were resistant to essentially every antibiotic tested. The findings, published in Frontiers in Antibiotics as part of the One Health Poultry Hub, provide one of the first systematic baselines of pathogen prevalence and resistance across the entire poultry distribution network of a major Indian state.

The scale of the potential problem is difficult to overstate. Foodborne pathogens infect an estimated 7.7 percent of the global population each year and contribute to roughly 7.5 percent of all deaths, with some 600 million outbreaks of foodborne illness occurring annually across 31 recognized illness types. India, as a major livestock-rearing nation, carries a particularly high burden: approximately 60 percent of its emerging and re-emerging pathogens are believed to pass from food and environmental sources to humans. Between 2008 and 2017, the country’s Integrated Disease Surveillance Program recorded more than 15,000 disease outbreaks, of which 2,688 were foodborne, and 58 of those were traced to meat, poultry, and eggs. Gujarat itself ranks among the Indian states with the highest reported average outbreak counts, making systematic surveillance in the region a pressing public health priority.

The research team, led by scientists at the Gujarat Biotechnology Research Centre with collaborators from the Royal Veterinary College in the United Kingdom, designed their study around the concept of poultry distribution networks. Rather than sampling randomly, they mapped the commercial pathways along which broiler chickens and indigenous desi chickens move from farms to consumers, then selected eight cities—Ahmedabad, Bharuch, Bhuj, Godhra, Himatnagar, Rajkot, Surat, and Vadodara—based on poultry density and network position. This approach reflects a key insight of modern food safety science: pathogens do not spread uniformly across a landscape but travel along the same routes as the animals themselves, concentrating risk at particular hubs of production, transport, and sale.

Between August 2021 and March 2022, the team collected 750 cecal samples from chickens to detect Campylobacter species, 150 cloacal samples for E. coli, and 150 environmental swabs from farm and shop surfaces to screen for non-typhoidal Salmonella. Only birds that appeared healthy and met breed-specific weight standards were included, meaning the study likely understates the true pathogen load. Campylobacter was cultured using the international ISO 10272-1:2017 protocol on selective charcoal cefoperazone deoxycholate agar under microaerophilic conditions at 42 degrees Celsius, the temperature at which these thermophilic bacteria thrive while competing microbes are suppressed. Identification proceeded in stages: biochemical tests, then matrix-assisted laser desorption ionization mass spectrometry, then multiplex PCR targeting genus- and species-specific genes, and finally 16S ribosomal RNA gene sequencing to confirm the most definitive identifications.

The results revealed a striking pattern of geographic and biological heterogeneity. Of the 750 cecal samples, 77 yielded confirmed Campylobacter isolates: 56 were Campylobacter coli, giving an overall prevalence of 7.46 percent, and 21 were Campylobacter jejuni, at 2.8 percent. Statistical analysis showed a significant association between city and C. coli prevalence, with Rajkot recording the highest rate at 13.04 percent and Himatnagar and Vadodara the lowest. Peak positivity appeared in broiler shop samples from Surat at 17.5 percent and in desi chickens from shops in Bhuj at 16.7 percent. Meanwhile, E. coli turned up in 51.33 percent of the sampled birds, a much higher rate that nonetheless varied far less between cities, suggesting this commensal-turned-opportunist is distributed fairly uniformly across the region’s poultry operations.

Perhaps the most intriguing biological finding concerned the desi chickens, India’s indigenous, often free-range birds. Not a single C. jejuni was detected in any of the 240 desi shop samples, while C. coli was present in 10 percent of them. This pattern held across every city. The researchers suggest two non-exclusive explanations: desi birds may possess inherent resistance to C. jejuni colonization, possibly rooted in genetic differences in gut microbiota or mucosal immunity, or their scavenging lifestyle simply exposes them to environmental C. coli rather than the dense horizontal transmission of C. jejuni that characterizes crowded commercial flocks. Farm-raised broilers showed the opposite tendency, with C. jejuni detected at 4.8 percent versus 2.4 percent for C. coli, reinforcing the idea that production system shapes which pathogen dominates. The study also noted seasonal effects, with Campylobacter prevalence dipping during the monsoon and rising from January to March.

The antimicrobial susceptibility testing painted a grimmer picture. Using the Kirby-Bauer disc diffusion method with 34 antibiotics for Campylobacter and 35 for E. coli across nine drug classes, the team found resistance exceeding 80 percent among Campylobacter isolates against a long list of clinically important drugs, including piperacillin/tazobactam, ampicillin/sulbactam, azithromycin, penicillin, and tetracycline. In total, 55.74 percent of Campylobacter isolates were multidrug-resistant. The E. coli results were even more dramatic: every one of the 77 isolates was resistant to vancomycin, a glycopeptide reserved as a last-line treatment for Gram-positive infections in humans, while 61.03 percent of E. coli isolates met the criteria for extensive drug resistance and 9.09 percent were pan-drug resistant. Nearly 30 percent of E. coli isolates showed resistance spanning glycopeptides, nitrofurantoin, macrolides, tetracyclines, beta-lactams, and fluoroquinolones.

Why does resistance reach such levels here? The authors point to the common practice in the study region of administering antibiotics prophylactically, as feed additives to keep flocks healthy. Farmers frequently use enrofloxacin, neomycin, levofloxacin, oxytetracycline, gentamicin, amikacin, and doxycycline, and antimicrobials are easily purchased over the counter without veterinary prescription. Resistance to one class of antibiotics can trigger or spread resistance to others, even those not present in the feed, because the underlying resistance genes often travel together on mobile genetic elements. The multiple antibiotic resistance index, which measures the proportion of tested drugs an isolate resists, exceeded the 0.2 threshold that signals high-risk environments for resistance gene dissemination in 60 of 61 Campylobacter isolates and all E. coli isolates.

The study is not without limitations, which the authors acknowledge candidly. Participation was voluntary, potentially introducing selection bias, and clinically ill birds were excluded, likely lowering measured prevalence. The sampling window could not capture the full seasonal range, and environmental surveillance relied on surface swabs rather than bulk soil samples, which may explain why no non-typhoidal Salmonella was detected—a null result that contrasts with studies elsewhere in India and abroad. Future work incorporating deeper soil sampling, along with water, feed, and airborne sources, would give a more complete picture of transmission routes through the poultry environment.

Nevertheless, the implications are clear. Raw or improperly cooked poultry meat can serve as a vehicle for transmitting these resistant organisms to humans, and the high prevalence of resistance against first-line clinical drugs poses a genuine threat to treatment options for foodborne infections. The researchers argue that coordinated policy action is needed at every stage of the food chain: regulating antibiotic use, mandating veterinary oversight of prescriptions, improving farm hygiene and biosecurity, and establishing continuous surveillance of resistance patterns in poultry, the rearing environment, and human populations. As India’s appetite for poultry continues to grow alongside intensification of production, the study stands as a warning that the same networks moving birds to market can also move something far harder to contain—bacteria that no longer respond to the drugs designed to stop them.

Subject of Research: Prevalence and antimicrobial resistance of Campylobacter and E. coli in Gujarat's poultry distribution network

Article Title: Prevalence and antimicrobial resistance profiles of Campylobacter coli, Campylobacter jejuni, and Escherichia coli in the poultry distribution network

Article References: Dantroliya, S., Chavan, M., Mittra, D., Pandit, R., Tomley, F., Blake, D., Koringa, P., Joshi, C., Shekh, S., Joshi, C., & Joshi, M. (2026). Prevalence and antimicrobial resistance profiles of Campylobacter coli, Campylobacter jejuni, and Escherichia coli in the poultry distribution network. Frontiers in Antibiotics, 5, Article 1875259. https://doi.org/10.3389/frabi.2026.1875259

Image Credits: AI Generated

DOI: 10.3389/frabi.2026.1875259

Keywords: Campylobacter coli, Campylobacter jejuni, Escherichia coli, antimicrobial resistance, poultry, Gujarat, One Health, foodborne pathogens, live bird markets, broiler chickens, drug resistance, food safety