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Probiotic bifidobacteria resistant to anti-TB drugs

Serious chance that resistance may spread through horizontal or vertical gene transfer, researchers say.

K. S. Jayaraman

doi:10.1038/nindia.2018.127 Published online 29 September 2018

A commonly used probiotic organism bifidobacteria carries genes capable of conferring antibiotic-resistance to a host of anti-tubercular drugs, new research says1. The study sounds alarm bells on the indiscriminate and rampant use of  such 'good bacteria' in the booming probiotics industry.

Probiotics are living organisms that several companies market as foods or supplements offering protection against diarrhoea and a host of other diseases. Researchers at the Central Food Technology Research Institute (CFTRI) in Mysuru have now warned that one such probiotic – bifidobacteria belonging to Bifidobacter genus – shows the "highest possible resistance" to drugs, such as rifamycin, isoniazid, streptomycin and pyrazinamide, used in the treatment of tuberculosis (TB).

The research team led by Kammara Rajagopal discovered the mechanism behind the antibiotic-resistance of bifidobacteria genes. This raises important questions on the invalidated and indiscriminate use of bifidobacteria as food, their report says.

TB requires long term treatment and so offers a good window for transfer of resistant genes, Rajagopal said. "Bifidobacteria resistant to  anti-tubercular drugs can transfer the resistance genes to  Mycobacterium tuberculosis and other susceptible bacteria in the gut," he said suggesting careful use of the biobacterium species.

"The trouble with the use of antibiotic-resistant probiotics is the serious chance that resistance may spread through horizontal (between organisms) or vertical (from parent to offsprings) gene transfer", the report says.

“It may therefore be safer to use only antibiotic-sensitive microbes as probiotics, or use antibiotic and probiotic therapy only after experimenting for the purpose,” Rajagopal said. "Perhaps the Food Safety and Standards Authority of India should start assessing individual probiotic microbes for antibiotic resistance markers before marketing." 

The authors say their study is the first to describe the process by which anti-tubercular drug-resistant probiotic microbes acquire such resistance. "Further research is essential to determine whether antibiotic resistance gene transfer can occur between bifidobacteria and other enteric bacteria." 

Vinay Nandicoori, a tuberculosis researcher at the National Institute of Immunology in New Delhi says the study shows that Bifidobacterium adolescentis, which is part of the gut microbiota, is naturally resistant to anti-TB drugs. “This provides a strong basis for future trials using animal models to test use of Bifidobacterium adolescentis as a probiotic in anti-TB treatment,” he told Nature India.


References

1. Lokesh, D. et al. Bifidobacterium adolescentis is intrinsically resistant to anti tubercular drugs. Sci. Rep. 8: 11897 (2018) doi: 10.1038/s41598-018-30429-2