Antibiotic resistance, where several strains of pathogens are developing resistance to some of the most commonly used antibiotics, is a serious threat, particularly to people in hospitals and those who have compromised immune systems. Whilst developed resistance is a very real threat, that some bacteria are “naturally” resistant to antibiotics should not be forgotten.
New research suggests some bacteria in the human body have had the ability to resist antibiotics and this has been so long before antibiotic drugs were used to treat diseases. This conclusion has been drawn from a study of a tribe of Yanomami Amerindians in a remote mountainous area in southern Venezuela.
The tribe has been relatively isolated from other societies for thousands of years. For this reason, the tribe members have a different and scientifically interesting collection of bacteria. From a review of the bacteria, and with the use of molecular biological methods, scientists have found the tribe people carry genes resistant to most antibiotics.
The resistant bacterial populations were recovered from skin, mouths and the guts of the Yanomami. The diversity of all of the organisms was greater than a typical population from a typical town in the U.S. Of the antibiotic resistant organisms, these bacteria would deactivate a range of antibiotic drugs. This was shown in some laboratory studies where bacteria isolated from the tribe were exposed to modern medicines under laboratory conditions. Among the drugs rendered ineffective were third- and fourth-generation cephalosporins, which are invariably the antibiotics of last resort designed to treat patients with serious infections.
Because the Yanomami would not have been exposed to antibiotic drugs, that they carry resistant genes means they must have developed resistance through natural antibiotics. One likely source is from soil fungi and bacteria. Many organisms, particularly those found in the soil, produce antibiotics that are designed to kill competitors.
To explain how bacteria can resist drugs they never encountered, the theory of cross-resistance has been put forward. This is when genes that resist natural antibiotics also have the ability to resist related synthetic antibiotics.
By further studying the Yanomami researchers hope to gain insights into how people in industrialised countries deal with diseases and also to learn more about how antibiotic resistance develops within a bacterial community. One school of thought thinks modern Western diet has strongly influenced the types of microorganisms found within the human gut and that this has some health implications.
The research was conducted at Washington University in St. Louis. The findings have been published in the journal Science Advances. The research paper is titled “Microbiome of uncontacted Amerindians.”