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Researchers in Chile, studying the effects of climate change on microbes trapped in ice for thousands of years, discovered bacteria in Antarctica that contain antibiotic resistance genes. Microbiologists have described the evolution of the “superpowers” of Antarctic bacteria in an article in the journal Science of the Total Environment.
- Bacteria collected in Antarctic soil samples proved resistant to antibiotics and antibacterial agents (copper, arsenic and cadmium)
- Their presence in the environment where antibiotics are found will cause them to spread rapidly
- Research on Antarctic bacteria may provide clues to those looking for new antibacterial drugs
- More information can be found on the Onet homepage
Superbacteria hyperimmune
The head of the research group, Dr. Andres Marcoleta, emphasized that genes supporting survival in extreme conditions simultaneously confer natural resistance not only to antibiotics, but also to disinfectants.
‘We know that the soil of the Antarctic Peninsula, the area most affected by ice melting, is home to a wide variety of bacteria,’ said Dr Marcoleta. Some of them are potential sources of antibiotic resistance genes found in mobile DNA fragments and plasmids that can be passed on to bacteria that cause infections in humans and animals.
Dr. Andres Marcoleta, assistant professor at the Faculty of Biology at the University of Chile, and his team conducted two expeditions to the Antarctic Peninsula and South Shetland Islands in 2017-2019. Scientists took soil samples and, using modern equipment for measuring environmental parameters, tried to determine how resistant the microorganisms living there are. They exposed them to antibiotics commonly used to treat infectious diseases and agents with antibacterial properties such as copper, arsenic and cadmium. About 20 strains of bacteria exhibited the characteristics of “hyper-resistance”.
The rest of the text below the video.
– Virtually no antibiotic hurt themperhaps antibiotic resistance helps them resist the toxic compounds found in their natural environment, says Dr Marcoleta.
– The genes that determine antibiotic resistance, according to the available data, already existed before the discovery and application of antibiotics – comments Prof. dr hab. Waleria Hryniewicz, specialist in the field of medical microbiology.
– Chilean research is not the first to talk about it, but another one that strengthens and expands our knowledge about the origin of these genes. There is a large reservoir of potential resistance genes in bacteria that live in the wild (Ang. the environmental resistome). It consists of the genes of microbes that produce antibiotics in order to survive in their presence. They must ensure their own safety so as not to die from the antibiotic produced. However, the genes originally responsible for other functions in the cell have a much larger pool and greater importance, and this has been shown by studies of historical samples from the virgin areas of the MacKay Glacier in Antarctica, as well as the Bering permafrost from 30 years ago. years – says the expert, adding:
– The latter, published by Canadian scientists in 2011, showed the presence of ancient genes encoding resistance to β-lactam antibiotics, tetracyclines and glycopeptides, similar to modern vancomycin resistance genes, which most likely were responsible for various metabolic processes of microorganisms.
The word “superbacteria” is not a medical term, although this is how we refer to bacteria that are resistant to many antibiotics or contain a “super-resistance gene” (NDM-1 gene – New Delhi-Metallo-beta-lactam-1) that encodes antibiotic inactivating enzymes. This gene is found in the bacterium Klebsiella pneumoniae NDM, first detected in India in 2008 when treating a urinary tract infection in a Swedish tourist (hence the colloquial name of the New Delhi bacterium).
Pseudomonas and Polaromonas bacteria under a magnifying glass
– The research of scientists from Chile, thanks to the use of modern genomic methods, significantly enriches our knowledge about the presence in the Antarctic environment, i.e. in the area not exploited by man, of a huge variety of bacterial species, including potentially pathogenic for humans (e.g. Pseudomonas) having various, own, not acquired, genes for resistance to antibiotics, heavy metals and disinfectants – explains Prof. Hryniewicz. And adds:
– They indicate the existence of a large number of reservoirs of potential resistance genes in a very wide group of bacteria that are originally responsible for other functions in the bacterial cell. Meanwhile, the widespread use of antibiotics drives them to “fight” antibiotics. It should be emphasized that in the evolutionary process these genes “migrated” from the chromosome to mobile genetic elements (plasmids, trasnsposons). Their presence in the environment where antibiotics are found will cause them to spread rapidly. They can also be transmitted between species, i.e. to pathogenic microorganisms for humans. The soil of the Antarctic Peninsula contains particularly interesting bacteria – Pseudomonas, related to the microorganisms responsible, for example, for cystic fibrosis.
A plasmid is an extrachromosomal DNA that occurs in the cytoplasm of a cell independently of the chromosomal DNA, characteristic of bacteria, although it has also been identified in cyanobacteria and yeasts.
The plasmid can replicate itself, making one or more copies per cell. It contains genes that are not essential for growth and survival, but impart specific traits, such as resistance to antibiotics or heavy metals (mercury, nickel, cobalt, cadmium, etc.). One plasmid can carry resistance to several types of antibiotics.
Plasmids can be transferred in bacterial cells during cell division or by horizontal gene transfer (between different bacterial species).
Fortunately, all indications are bacteria Pseudomonas antarcticadominant in the Antarctic Peninsula are not pathogenic, however they can be a source of resistance genes that are relatively easily transferred to pathogenic Pseudomonas. Common disinfectants will not stop these subacteria, containing compounds of heavy metals, e.g. copper and chlorine or quaternary ammonia.
Another common type of bacteria in Antarctic soil is Polaromonaswhich also have the potential to inactivate beta-lactam antibiotics (a group of antibiotics that includes: penicillins, cephalosporins, carbapenems, monobactams).
Recall that penicillins are used to treat infections such as: streptococcal infections (angina, otitis media, abscesses, pyoderma, sepsis), staphylococcal infections (abscesses, osteomyelitis, sepsis), gonorrhea, pneumococcal pneumonia, meningococcal meningitis, diphtheria, tetanus, anthrax and syphilis.
Dr. Marcoleta claims that Polaromonas have already been found in inhabited areas of Siberia, where pathogenic bacteria are also present. Probably the bacteria typical of the polar regions came into contact with pathogenic bacteria, which could lead to the exchange of genetic material.
Why is the discovery of Chilean researchers a cause for concern? Dr. Marcoleta says that infections caused by bacteria that are highly resistant to the available drugs are becoming more and more common in the world. However, in the pages of “Science of the Total Environment” we read: «Antarctic bacterial resistance gene could be passed on to other pathogenic bacteria, causing serious global health problems«.
– Antibiotic resistance has become one of the most serious threats to human health and life, significantly limiting effective therapeutic options – says Prof. Waleria Hryniewicz.
– There is a dynamic growth of antibiotic-resistant bacteria responsible for the most common human infections, especially Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumanni and cocci such as: Staphylococcus aureus, Enterococcus spp and Streptococcus pneumoniae. The scale of the phenomenon is so huge that we hear about the antibiotic resistance pandemic more and more often. For years, the causes of resistant bacteria and the sources of the genes responsible for this phenomenon have been analyzed.
According to research published in January this year. in the prestigious British medical journal “The Lancet”, 2019 million people worldwide died from superbug infection in 1,2. Faced with antibiotic resistance, the World Health Organization has already announced a global health crisis and has set up a working group to investigate alternative therapies.
– Research by Chilean scientists should be an important element of the antibiotic resistance prevention strategy, as well as a guide to the search for new antibacterial drugs covering the spectrum of bacteria with new resistance mechanisms – notes Prof. Hryniewicz.
Some properties of Antarctic bacteria have already interested biotechnologists. Their incredible potential was confirmed not only in the field of production of new antibiotics, but also in the bioremediation of contaminated sites, neutralization of toxins and sustainable production of biopolymers, which are biodegradable substitutes for petroleum-based plastics.
Bacteria and climate change
Chilean scientists recall that the COVID-19 pandemic has taught mankind that microorganisms, especially pathogens, can cause global effects.
‘It is worth considering whether climate change could have an impact on the incidence of infectious diseases,’ suggests Dr Marcoleta. – One can imagine a scenario where resistance genes leave their reservoir and contribute to the expansion of infectious diseases.
– As a result of the evolutionary response to the strong selection pressure resulting from the overuse of antibiotics, there may be a rapid emergence and intensive spread of resistance among environmental bacteria, especially horizontal gene transfer within species and interspecies – emphasizes Prof. Hryniewicz.
Chilean scientists have already started a new in-depth research project called “Anillo mBioClim”. It aims to determine how resistant bacteria can be brought from Antarctica to other parts of the world, whether climate warming affects these bacteria, and how their genetic information can be transmitted by plants or animals living there.
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