A nursery of drug resistance

Friendly gut bacteria can transfer resistance traits to pathogens

August 26, 2018 12:02 am | Updated 12:09 am IST


Scientists at the Translational Health Science and Technology Institute (THSTI), Faridabad, Haryana, have found that friendly gut bacteria are a reservoir of drug resistance genes which, when transferred to disease-causing bacteria, may make them untreatable.

Antibiotic resistance is emerging as a threat to the successful treatment of infectious diseases, organ transplantation, cancer chemotherapy and major surgeries. Although a natural process involving changes at the genetic level, antibiotic resistance is now increasing due to indiscriminate antibiotic use in health care and the agriculture and veterinary sectors.

Gut bacteria used

In this case, researchers studied antibiotic resistance traits in dominant gut bacteria isolated from human faecal samples. Six healthy individuals who had not consumed antibiotics for the past six months were selected for the study. It was found that friendly gut bacteria from these individuals harboured resistance against multiple antimicrobials, which was attributed to the presence of a vast number of antimicrobial genes.

In all cases, the most abundant resistant genes were the ones associated with tetracycline resistance (an antibiotic used to cure cholera, malaria and other infections). It was followed by the beta-lactamase genes which function to negate the effect of medicines used to fight a broad spectrum of bacteria.

In-depth analysis showed the presence of several resistance genes for each class of antimicrobials.

“Isolation of commensal gut bacteria and their culture in the laboratory was challenging. The significance of molecular studies to combat antibiotic resistance and guide treatment regimens cannot be underrepresented,” said Dr. Bhabatosh Das, who led the research team.

The researchers found that the antimicrobial genes are physically connected to genetic elements that could aid their transfer to their progeny and surrounding bacteria. It is cause for concern as friendly gut bacteria can transfer resistance traits to pathogens, supported by the observation that cholera-causing bacteria have been found capable of taking DNA from their surroundings.

‘Need for research’

With a high burden of infectious diseases such as tuberculosis and diarrhoeal diseases, India’s fight against antibiotic resistance has been escalated because of poor sanitation and malnutrition. The resistance patterns among organisms are also found to vary with their geographical location. “It was surprising to see that friendly gut bacteria fostered resistance traits. This unexplored arm acts as a huge potential source of antibiotic resistance dissemination. We are currently working to re-sensitise these bacteria and make them antibiotic-sensitive,” Dr. Das said. “There is a pressing need to pursue active research to overcome antimicrobial resistance crisis in India. Strategic use of antibiotics would be a crucial step in the process,” he added.

The findings have been published in the journal, Microbial Ecology . The study was funded by the Department of Biotechnology. — India Science Wire

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