When you travel abroad, you get exposed to different cultures, traditions and challenging experience. However, gaining new life insights may not be the only thing you get from an expat life, rather you might get very minute changes that you don’t even realize them. Such changes will take place very deep inside you; in your gut.
The human gut provides shelter for millions of bacteria, fungi and archaea; constituting what is widely known as human gut microbiome (HGM). Generally, HGM is composed of three majors groups: Prevotella, Bacteroides and Ruminococcus. Nutritional habits and environmental factors widely affect the distribution and balance between different groups. For instance, Prevotella group is mostly associated with carbohydrates and simple sugars intake, while Bacteroides group thrives with higher consumption of animal proteins, amino acids and saturated fats. Thus, the diet composition determines the dominating group in our guts.
The microbial communities constituting HGM help in digesting certain kinds of foods as a sort of symbiotic relationship with humans. Additionally, HGM triggers the first spark of the innate immune system in infants leading to a lifetime immunity and adaptive response. In context, HGM plays a critical role in fighting pathogenic microbes by suppressing the domination of undesirable ones.
Unsupervised use of antibiotics without proper medical prescription harms our microbiome and alters the delicate balance between different groups. Adding to that, it accounts for an increment in numbers of antibiotic-resistant bacteria which are mostly pathogenic microorganism. Unfortunately, such antibiotic resistance can’t be restricted to a certain population or a limited geographical area, rather it tends to spread out across different continents raising a serious global concern.
A recent Swedish study carried out on 35 university exchange students has shown that our microbiome can gain lots of antibiotic-resistant bacteria through food and water when we travel abroad, even without being ill.
The authors of the study sequenced bacterial DNA of stool samples collected from the exchange students before and after travelling for a period of 15 to 150 days to India or Central Africa. They found a relative increase in the abundancy of antibiotic resistance genes, most prominently for genes encoding resistance to sulfonamide, trimethoprim and beta-lactams.
“We can get resistant bacteria into our bodies through the food and water in the countries we visit. The resistant bacteria can spread without ourselves becoming ill and notice them, and therefore move quickly across borders” says Joakim Larsson, professor of environmental pharmacology at the Sahlgrenska Academy, University of Gothenburg, and a co-author of the study.
More interestingly, the authors observed an increase of DNA mobile elements and genes encoding for enzymes that help in moving and translocating DNA fragments between different bacteria. Also, they reported a remarkable stability of the microbiome changes that happened during the exchange period which comes in line with previous studies.
“Our results suggest that not only the overuse of antibiotics is responsible for the dramatic increase in resistance. Since resistance can spread to healthy people, hygiene is very important to limit the spread of such worrying situation” says Anders Johansson, associate professor of infectious diseases at Umeå University and senior author of the study.
The researchers concluded that contaminated food or water resources as well as close contact with an environment containing antibiotic-resistant bacteria might lead to a global pandemic situation. So, efforts should be made to improve the standard of living in a global perspective, and more resources should be devoted to increase the awareness of diseases and resistant bacteria.
The research was published in journal Antimicrobial Agents and Chemotherapy.
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