Could taking antibiotics increase your risk of STDs?

Taking antibiotics could increase a person's chance of being diagnosed with a sexually transmitted disease, a new study warns. The drugs disrupt the microbiome of the vagina, resulting in a loss of bacterial diversity, scientists discovered.

This, in turn, increases a compound that blocks the immune system's T-cells from migrating to the vaginal tissues to fight any infections.

Researchers in Korea and Japan found mice treated with antibiotics succumbed to HSV-2, a type of genital herpes infection, faster than a control group not given the drugs. The mice were treated with antibiotics for four weeks before they were exposed to the HSV-2 virus.

Microbiota are known to play a vital role in antiviral immunity, providing signals to the immune system. However, the impact of an imbalance of bacteria in the microbiota, known as dysbiosis, remains unclear.

As a result, a team of scientists led by Ji Eun Oh from the Korea Advanced Institute of Science and Technology examined the role dysbiosis plays.

The authors of the study, published in the Proceedings of the National Academy of Sciences, found the imbalance is caused by oral antibiotic treatment.

Furthermore, they note it 'directly impairs antiviral immunity following viral infection of the vaginal mucosa'.

They discovered mice treated with antibiotics were more susceptible to becoming infected with a type of genital herpes virus, in comparison with mice given a placebo of water.

In addition, their findings revealed those antibiotic-treated mice infected with the herpes virus showed a 'delayed viral clearance at the site of infection', meaning the virus took longer to be treated.

All the mice treated with antibiotics prior to being exposed to the herpes virus died within 11 days of infection. The authors noted: 'Taking these data together, we find that depletion of commensal bacteria results in a severe defect in antiviral protection following mucosal HSV-2 infection.'

The scientists found that the imbalance in bacterial diversity in the vaginal microbiota in mice treated with the drugs, triggered an increase in an alarmin called IL-33.

This blocked the immune system's T-cells from migrating to the vaginal tissues, and also stopped them secreting antiviral cytokines, which are crticial in the fight against viruses.

The authors wrote: 'Our present study demonstrates that inhibitory signals induced by the depletion of commensal microbiota also affect antiviral immunity.

'Taken together, our findings provide a unique insight into the role of commensal bacteria in maintaining the integrity of surface barrier epithelial cells by preventing pathogenic bacteria colonization, thereby supporting a micro-environment conducive to antiviral defense.'

The scientists concluded that their results have implications for the use of oral antibiotics, and increased risk of STDs.    

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