Microbes vs. super-microbes
A weapon against antibiotic-resistant Staphylococcus aureus found in other bacteria
Vasily Parfenov, Naked Science
The combination of two specific bacterial proteins – bacteriocins – made methicillin-resistant Staphylococcus aureus (MRSA) susceptible to penicillin again. This discovery provides new opportunities to combat a variety of nosocomial and intractable bacterial infections.
Scanning electron microscopy of a biofilm of methicillin-resistant Staphylococcus aureus (MRSA) after exposure to a three-component drug, which included garvicin KS, micrococcin P1 and penicillin G. The destruction of cell membranes and the general thinning of the biofilm are clearly visible. Sequential magnification of 3500, 7500, 20,000 and 50,000 times (scale rulers of 10, 2, 1 and 1 micrometer, respectively). Figure from the article by Kranjec et al.
Methicillin–resistant Staphylococcus aureus is the cause of a wide range of seriously curable human diseases and conditions. Among them are acne, erysipelas, pneumonia, meningitis, osteomyelitis, endocarditis, infectious and toxic shock and sepsis. Even if the disease is caused by another pathogen, MSRA can lead to serious complications and death. According to the World Health Organization, antibiotic–resistant strains of bacteria are in fifth place among all the key threats to human health.
A team of biologists from the Norwegian University of Life Sciences (Norwegian University of Life Sciences) together with Indian scientists from the non-profit organization LEPRA Society studied the effects of several bacteriocins on biofilms of Staphylococcus aureus.
The results of the study are published in the peer-reviewed journal npj Biofilms and Microbiomes (Kranjec et al., A bacteriocin-based antimicrobial formulation to effectively disrupt the cell viability of methicillin-resistant Staphylococcus aureus (MRSA) biofilms).
The ability of bacteriocins to destroy the outer shells of pathogenic bacteria has been known to scientists for a long time. In fact, this is the main function of this class of proteins – it is a kind of weapon of microorganisms against competitors. In recent years, some bacteriocins have attracted the attention of biologists due to their high effectiveness against a wide range of pathogens dangerous to humans. One of such potential substitutes or "helpers" of antibiotics is garvicin KS.
In their study, Norwegian and Indian scientists suggested that using two bacteriocins at the same time can increase the effectiveness of each of them. They experimented with several strains of methicillin-resistant Staphylococcus aureus. He is famous for almost completely ignoring the beta-lactam antibiotic benzylpenicillin (penicillin G, PCN G). In a series of experiments, two strains – USA300 and ATCC 33591 – were suppressed.
The combination of three drugs – garvicin KS, micrococcin P1 and trivial penicillin G – practically destroyed ATCC 33591 biofilms. On the USA300 strain, the efficiency was somewhat lower, but also impressive. Scientists suggest the following mechanism of such treatment. Garvicin KS destroys biofilms into which Staphylococcus bacteria are collected. Micrococcin P1 enhances this effect and damages the cell membranes of bacteria. Only two of these drugs already have a powerful effect and inhibit the growth of staphylococci. Adding an antibiotic to them accelerates the process and finally destroys the bacteria.
Despite the fact that some MSRA strains could not be "penetrated" with such a cocktail, progress is evident. Biologists plan to continue their research and develop more universal combinations of bacteriocions with each other or with antimicrobial drugs. The results of the above work already allow us to start creating medicines against many strains of Staphylococcus aureus. And this will lead to the preservation of thousands of lives.
Nosocomial infections caused by antibiotic–resistant bacteria are a real scourge of modern medicine. Staphylococci, for example, adapt quickly to new medications by themselves, but if they form biofilms, they become virtually invulnerable to most treatments.
Portal "Eternal youth" http://vechnayamolodost.ru