study: US migration and gut antibiotic resistance genes

Look, us mere mortals never really get to find out what is going on in the world of science. Well, not unless it’s (sometimes) sensationalised in the press. So, we wanted to bring you a snapshot of the latest science to whet your appetite to find out more if it’s something that piques your interest. Or, simply to keep you all in the “gut world” loop. Remember most of the studies are VERY new science, so keep your critical thinking cap on!

Background

Antibiotic resistance (when antibiotics are no longer effective in stopping a bacterial infection) is a major healthcare problem around the world caused by the overuse of antibiotics. Around 700,000 people die every year because of antibiotic resistance.

A large number of antibiotic resistance genes can be found in our guts.
Although migration is quite common nowadays. Little is known about its impact (and its associated changes in diet or geography) on antibiotic resistance genes found in the gut.

This study was published in the Clinical Infectious Diseases Journal on 4th November 2019. And examined the impact of migration from Thailand to the United States on the composition of antimicrobial resistance genes found in the gut among 50 women. There was no follow-up.

Key Findings

Migration from non-industrialised societies (Thailand) to industrialised societies (United States) leads to an increase in the amount and diversity of antibiotic resistance genes found in the gut.

This was a cohort study where 55 stool samples of 50 women were analysed. 15 Thai women living in Thailand; 5 Thai women that moved to US in the past 6 months (they had 1 sample analysed 1 month before they moved to US and 1 sample analysed 6 months after they moved to US); 15 Thai women living in US for 30+ years and 15 healthy women European American controls.

Study Findings

Thai women living in US for 30+ years had a wider range and more of antibiotic resistance genes in their guts than Thai women living in Thailand. The gut antibiotic resistance genes of Thai long-term US residents became more similar to that of European Americans. Resistance to commonly used antibiotics such as tetracycline, vancomycin or beta-lactam was found in these participants.

Even the guts of Thai women who were living in the US for 6 months had increased antibiotic resistance genes compared to just before they arrived in the US.

Study Limitations

While these results are very interesting, it only had 50 women participants from Thailand. And therefore we need larger and more ethnically diverse cohorts. Cohorts that include both men and women to understand better the impact of migration on the gut antibiotic resistance genes. There was also no control arm of this study. This was needed to account for possible antibiotic use upon migration. Since this study has no follow-up yet we do not know whether the women who have many antibiotic resistance genes will actually develop antibiotic resistance.

Conclusion

This study shows how sensitive to changes in geography and diets the gut antibiotic resistance genes are but further research is needed to apply this to diverse populations.

About the author

This study shows how sensitive to changes in geography and diets the gut antibiotic resistance genes are but further research is needed to apply this to diverse populations.