Drug-resistant bacteria found in fowls in remote Andaman and Nicobar Islands

A team of scientists from two government research institutes has detected strains of drug-resistant bacteria in fowls reared in some of the remote islands of the Andaman and Nicobar Islands.

Some strains of these bacteria - Escherichia coli, Salmonella enterica and Klebsiella pneumoniae – are responsible for life-threatening diseases including Hemolytic uremic syndrome, pneumonia, diarrhoea and typhoid among others in humans.

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“What comes as a concern is that some of these drug-resistant strains were detected in Nicobari and desi varieties of fowls, reared by tribal people in their backyards in some of the remote islands such as Nicobar. These tribal people and the fowls have no exposure to antibiotics,” said Jai Sunder, principal scientist and head of the animal science division at Central Island Agricultural Research Institute (CIARI).

The findings made by the scientists from the West Bengal University of Animal and Fishery Sciences (WBUAFS) in Kolkata and the Central Island Agricultural Research Institute under the Indian Council of Agricultural Research (ICAR-CIARI) in Port Blair have been published Frontiers in Veterinary Science, an international peer-reviewed journal in January this year.

“We collected 199 cloacal swab samples from five breeds of fowls between November 2019 and January 2021 from three districts – South Andaman, North and Middle Andaman and Nicobar,” said Sneha Bhowmick, the principal research scholar of the study.

In the laboratory the researchers identified around 425 strains of bacteria. While Klebsiella pneumoniae was found to be the most prevalent, Salmonella enterica and E. coli came second and third.

“One out of every three strains (more than 33%) collected were found to be producing the enzyme beta-lactamase, which made them drug-resistant. While 61% - 76% of the strains were resistant to oxytetracycline, the lowest resistance was against gentamicin (15– 20%),” said Surajit Pal, another researcher associated with the study.

Antimicrobial resistance in livestock is a global challenge as the bacteria possessing the resistance genes can be disseminated into the human food chain through cross-contamination by means of occupational exposure, contaminated environment, and consumption of undercooked animal-origin food.

“Once the drug-resistant strains enter the body they can change the nature of other harmless strains of the same species in our body, making them drug-resistant too. They can also set off chain reactions, which may ultimately make other bacteria in humans, drug resistant,” said Indranil Samanta, principal investigator of the study and assistant professor of veterinary microbiology at WBUAFS.

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The scientists said that while some bacterial strains may have the intrinsic capacity to produce the enzyme beta-lactamase, which made them drug-resistant, they apprehend that the strains may have also come from migratory birds which frequent the islands.

“The 2004 tsunami has made some land changes in some of the islands of the archipelago and new wetlands have appeared. These have become the haven for migratory and other birds. More studies are needed to find out where these drug-resistant strains came from,” said Samanta.