Carried like stowaways in the guts of international travellers, new and potentially deadly strains of antimicrobial-resistant superbugs may be coming to a community near you, suggests new research from Washington University School of Medicine in St. Louis.
“Even before the COVID-19 pandemic, we knew that international travel was contributing to the rapid global increase and spread of antimicrobial resistance,” said Alaric D’Souza, an MD/PhD student at Washington University and a co-first author of the study to be published June 6 in Genome Medicine.
“But what’s new here is that we’ve found numerous completely novel genes associated with antimicrobial resistance that suggest a worrisome problem on the horizon.”
According to research, it has been found that international travellers often return home with an unexpected glut of new bacterial strains jostling for position among the thousands that normally reside within the gut microbiome. Poor sanitation, changing agricultural practices and poverty have turned many low-income, developing regions into hot spots for the spread of the diseases by bacteria, including infections that are increasingly resistant to a range of antibiotic drug treatments.
Among community residents and travellers through long exposure to contaminated drinking water and food, or poorly sanitized restrooms, restaurants, hotel rooms and public transportation are some reasons why high-population densities make it easy for these bacteria to be shared. Travellers have a high risk of spreading these novel bacteria to family, friends and other community residents back at home.
The research has been conducted with Maastricht University in the Netherlands, involved analyzing bacterial communities in the gut microbiomes of 190 Dutch adults before and after travel to one of four international regions where the prevalence of resistance genes is high: Southeastern Asia, South Asia, North Africa and Eastern Africa. Faecal samples analyzed as part of the study were randomly selected from a larger, multicenter investigation of about 2,000 Dutch travellers, the majority of whom were tourists, known as the Carriage Of Multi-resistant Bacteria After Travel (COMBAT) study.
“We found significant travel-related increases in the acquisition of resistance genes, abundance and diversity encoded by bacteria that are endemic to the region visited,” D’Souza said.
“These findings provide strong support for international travel as a vector for the global spread of clinically important antimicrobial resistance genes and highlight the need for broader surveillance of antimicrobial-resistant bacteria in the gut microbiomes of returning travellers.”
The new study was designed by co-senior authors John Penders, a medical microbiologist at Maastricht University, and Gautam Dantas, PhD, a professor of pathology & immunology at Washington University.
Manish Boolchandani, PhD, a member of the Dantas Lab during the research and a 2020 graduate of the university’s doctoral program in Computational and Systems Biology, is also the first author on the paper. The rapid spread of antimicrobial resistance like one of the most serious public health threats now facing the world which is looming medical catastrophe that could outweigh the chaos created by the COVID-19 pandemic, this has been described by the World Health Organization, the U.S. Centers for Disease Control and Prevention, and other agencies.
“While previous studies have scanned travellers’ stool samples for well-known antimicrobial-resistant bacteria, we used a combination of whole metagenome shotgun sequencing and functional metagenomics to identify both known and novel genes that code for antimicrobial resistance,” Dantas said.
In all, 121 antimicrobial resistance genes across the gut microbiomes of the 190 Dutch tarvellers were detected by the researchers. More than 40% of these resistance genes (51 of them) were only discovered using the more sensitive metagenomics technique, suggesting that potentially dangerous genes are being missed by the more conventional approaches.