You’ve most likely had an infection that required treatment with antibiotics. At the time that you were prescribed antibiotics, you probably heard that familiar spiel about needing to take the entire course of antibiotics even if you feel better before finishing them. You might be wondering, why does it matter? Hopefully after reading this post you will be able to answer that question for yourself.
As you might imagine, bacteria developing the ability to survive antibiotic treatment is bad news for us. This means that over time, our commonly used antibiotics are becoming less effective at killing bacteria. As bacteria evolves more antibiotic resistance, we may no longer be able to treat common infections unless we come up with another alternative treatment. It is important that we try to delay the evolution of antibiotic resistance as much as we can to buy time to develop other effective treatments. So what are the driving forces of bacterial evolution and what can we do about it?
Background:
About 70% of the planet is covered in water with about 60% of your body being made up of water. Lakes, rivers, and reservoirs contain some of the most diverse and abundant communities of bacteria according to a 16S rRNA gene study by Tamames et al. (2010). Our own microbiota interact daily with these different communities as we drink, bathe, and excrete bacteria. One of the more pressing issues in today’s modern medicine is antibiotic resistant bacteria that are becoming increasingly hard to treat. Antibiotic resistance is caused by evolution of bacteria, which is the bacteria gaining antibiotic genes that increase its fitness. In the presences of antibiotics, bacteria that are lacking a resistance mutation die, whereas bacteria with immunity to antibiotics have a higher survival rate. These antibiotic resistant bacteria then pass on that resistance to antibiotics to the next generation, as well as potentially other bacteria through lateral gene transfer, which is the transfer of genetic material between a parent and daughter bacteria. Continue reading “Antibiotic Resistant Bacteria in the Human Water Cycle”
The geographical location of the Yanomami tribe as a whole. The specific village exists in the highlighted region. (Image courtesy of Viralfast)
Background
The Yanomami people are patches of isolated South American tribes who occupy mountainous regions of southern Venezuela. Recently, a Yanomami tribe of 34 subjects discovered by helicopter, was investigated by a team of researchers who accompanied medical care professionals who were providing care to the villagers. These researchers, Clemente et. al. (2015), then wrote the paper, “The microbiome of uncontacted Amerindians’ to analyze this population which was uniquely untouched by Western Society. An interesting topic that this research paper addresses is antibiotic-resistant bacteria. Antibiotic-resistance are the adaptations of a bacterial species in response to antibiotics. Antibiotics are medications that have been developed in more recent times to destroy bacteria cells but not human cells. They do this by targeting specific differences between the two types of cells, for instance, penicillin inhibits the synthesis of the peptidoglycan layer of bacterial cell walls a feature not present in animal cells. Other bacteria have distinct DNA replication processes and some antibiotics are able to interrupt that function as well. This Yanomami population is intriguing because their microbiomes are likely the most accurate representation of an ancient human microbiome due to their isolation from the Western world. The presence of antibiotic-resistant bacteria in the Yanomami gut provides evidence for the claim that antibiotic-resistant bacteria have been around since before the invention of antibiotics, so stay tuned for a persuasive evidentiary argument further down. Clemente et. al.also state that the Yanomami population that is sampled is the most diverse microbiome ever recorded. It is important to understand what kind of diversity the researchers are talking about. The Yanomami show extremely high beta diversity when compared to Guahibo, Malawi, and U.S. populations but exhibit low alpha diversity amongst individuals in the village population. Beta diversity represents the differences in species composition among samples while alpha diversity is just the diversity of each sample. This means that the Yanomami microbiome sample is extremely unique but microbiomes within that sample are very similar, this is most likely due to the Yanomami leading vastly different lifestyles than Western societies and individuals in the village being in extremely close quarters with each other (eating the same food, drinking from the same water source, no waste removal, etc.).Continue reading “Which came first, antibiotics, or antibiotic-resistance? A study of Uncontacted Amerindians.”
