Chickens are creating more resistant bacteria – 01/21/2024 – Balance and Health

A study on commercial chicken farms in China revealed that E. coli and salmonella species share genetic elements in order to more effectively resist antimicrobial agents.

A study of samples from 10 chicken farms and slaughterhouses in China, containing Escherichia coli It is Salmonella entericarevealed that these bacteria managed to develop antimicrobial resistance (AMR) through the exchange of genetic information, using mobile genetic elements.

This property was already known, but “it is not completely clear to what extent this is possible between bacteria of different species, since most studies focus on a single species”, explains study co-author Tania Dottorini.

The researchers collected samples – feces, carcasses, feathers, feed, soil, used water, anal swabs, slaughterhouse surroundings and drinking water – from the same birds and locations. Both species investigated, normally present in both the animal and human food chain, are a potential source of food poisoning.

“We discovered for the first time that many samples of AND. colla and the S. entericain the context of the real world that we analyzed, presented the same mobile genetic elements”, continues the researcher. “This could indicate that these carriers of antimicrobial resistance are necessary for survival [das bactérias] within the host and in the environment.”

Data exchange is a factor in bacterial survival

The fact that the E. coli and the S. enterica sharing mobile genetic elements specifically related to AMR is a phenomenon “that has not been previously identified, but may be happening on a large scale in environments similar to the farms we studied.”

“The mobile genetic elements of the bacterial genome play a crucial role in the evolution of microbes, with repercussions on antibiotic resistance”, confirms Filipa Vale, specialist in microbial biology and genetics at the University of Lisbon.

According to her, the current study – in which she was not involved – showed that “real-world scenarios represent a significant threat of AMR transmission to humans and the environment, emphasizing the importance of studying mobile genetic elements among bacteria.”

Bacteria that threaten global health

Bacteria like E. coli and the S. enterica can cause potentially fatal diarrhea in humans, especially in low- to middle-income countries. Therefore, they are considered an important global threat to health and development.

The WHO (World Health Organization) calculates that antimicrobial resistance caused a total of 1.27 million deaths in 2019, in addition to contributing to 4.95 million. The fact is attributed to the “misguided and excessive use” of antimicrobials in humans, animals and plants.

Antimicrobial agents are medicines and chemicals used to combat bacteria. Its most common form is antibiotics, but they also include antiseptics, disinfectants and fungicides. They are used not only to treat infections in humans, but also to prevent them and promote the growth of birds on industrial farms.

In turn, bacteria have developed mechanisms against these agents, targeting AMR, to the point that antibiotics are becoming ineffective in treating several illnesses, even relatively harmless ones, such as urinary tract infections.

Special interest in lower-middle income countries

Another relevant fact from the present study is that, compared to similar European establishments, farms in China had a much higher number of mobile genetic elements.

According to Dottorini, these differences may be due to “variations in antibiotic use and intervention strategies”, and “these findings most likely apply to other geographic settings with antibiotic use practices similar to those in China.”

Dottorini also recalls that the study “only considered two species”: “It is likely that similar behavior will be observed in other bacterial species occupying this same microbiome. Future studies will expand our research in order to address this issue.”

Of special interest will be lower-middle income countries, where “intensive breeding strategies are being increasingly used and the regulation of antimicrobial administration tends to be less rigorous than in Europe”, anticipates the researcher.