2023-08-10 13:15:13
This is stated by the Argentine biochemist María Soledad Ramírez, who directs her own laboratory at the California State University of Fullerton, United States, where she investigates the resistance mechanisms of the bacterium Acinetobacter baumannii (Ab), which is part of the list of WHO critical pathogens because it no longer responds to available antibiotics.
During her recent visit to Buenos Aires, the expert spoke about the risk to public health of the existence of “superbugs” and presented the results of her latest work.
When he chose it as his object of study, in the early years of the 21st century, it had not yet become one of the main threats to public health. But for the biochemist María Soledad Ramírez, who was doing her postdoctoral research at the Faculty of Medicine at the University of Buenos Aires (UBA), the bacterium Acinetobacter baumannii (Ab) was very interesting due to its enormous genetic versatility and high rate of mortality it has when invading the human organism.
Two decades later, the World Health Organization (WHO) and the United States Centers for Disease Control (CDC) already include Ab on the list of critical pathogens and consider it a “superbug” because it is resistant to all available antibiotics. Ramírez, for his part, investigates from his own laboratory at the California State University of Fullerton, United States, how to counteract the lethal power of this bacterium that is contracted mainly in the hospital environment and causes pneumonia, septicemia and meningitis, among others. infections that can lead to death.
“He has a terrible adaptability. It can remain on a surface for more than 100 days… on a counter or in hospital equipment, for example. Once Ab has entered the hospital, it is almost impossible to eradicate,” Ramírez specified to the CyTA-Leloir Agency, who makes a forceful declaration of principles on his personal website: “Never underestimate the power of a bacterium again.”
The specialist studies the adaptation mechanisms of Ab and how it becomes resistant to different antibiotics, as a way of looking for new therapeutic alternatives against one of the major health problems of today. “Bacteria have acquired a terrible capacity for evolution, much greater than that of humans,” she said. And she graphed: “Just 15 years ago, a urinary infection was very easily treated with antibiotics. But today this is no longer the case and the information provided by the antibiogram is necessary to be able to determine the best way to address it”.
According to the scientist, this loss of drug efficacy has to do, in part, with a natural ability of bacteria to adapt, but she stressed that another cause is the misuse of antibiotics. “For example, when one takes it without being told to or interrupts the treatment prematurely because it already feels good, and even because doctors prescribe it ‘just in case’ or give in to pressure from patients,” he listed. she. Another big problem, she emphasized, is the use of antibiotics in livestock, where they are used as a growth factor or preventively so as not to affect production.
Although Ab is a bacterium more typical of hospitals and there are very few case reports at the community level, Ramírez explained that, since it is also associated with tropical climates, it is estimated that beyond resistance to antibiotics, climate change will also impact on the type of infection it causes.
Maria Soledad Ramirez. (Photo: Cal State Fullerton/CyTA-Leloir Agency)
looking for solutions
A recent WHO report calls the rapid worldwide spread of multi-resistant and “pan-resistant” bacteria (to all antibiotics) causing infections that can no longer be treated particularly alarming. “Antimicrobial drug resistance is one of the top 10 public health threats facing humanity,” he warned.
“We have fewer and fewer antibiotics that work and it is very difficult to develop a new one. Resistance always emerges; in some cases faster, in others slower, but it is a dramatic situation. What we, as researchers, doctors, and patients, can do is delay this resistance,” said Ramírez, who took advantage of his recent visit to Buenos Aires to present the results of his latest work to scientists from the Fundación Instituto Leloir (FIL), with whom maintains a permanent collaboration; especially with Rodrigo Sieira, from the Laboratory of Molecular and Cellular Microbiology.
But the new antibiotics are not without their setbacks either. Ramírez shared in his speech his conclusions about cefiderocol, one of the last antibiotics approved by the FDA, the United States drug regulatory agency, to treat serious infections caused by “superbugs.” “Although it is quite promising for its effectiveness, we are already seeing increases in resistance,” he said.
Cefiderocol, which is not yet marketed in Argentina, is a very particular substance because it is a hybrid of two antibiotics from the penicillin family (beta-lactams), to which they added a chemical compound that attracts iron (catechol). , an element that the bacterium needs when it is causing the infection. The Japanese laboratory that created it (Shionogi) named it “Fetroja” in reference to the Trojan Horse, since it “tricks” the bacteria into taking the iron it needs and, in the process, opens the door to an insidious enemy. The drug thus attacks the microorganism from two places at once: from the outside, through the porins or channels in its outer membrane, and from the inside, through the active iron uptake system.
“Reports in the medical literature have shown that, for the treatment of infections caused by Abs, cefiderocol is not as successful. Our studies carried out at the transcriptomic level in the laboratory could explain at least part of the reason: we have seen that the human protein HSA triggers a response in bacteria, which changes and decreases the expression of active iron uptake systems. Thus, the antibiotic is less effective,” explained Ramírez. And he said that they are now investigating whether there is a specific receptor for HSA.
The problem of antibiotic resistance is so great that it is predicted that by 2050 it will cause more deaths than cancer. Faced with this “hidden pandemic”, the use of various strategies to combat superbugs is evaluated, such as providing hospitalized patients with three different antibiotics or the combination of antibiotics-phages. Phages are viruses that infect bacteria. They would attack the membrane so that the antibiotic would then act. But it has not yet been proven and it is not very clear whether the phages are harmless to humans”, highlighted the scientist.
With the objective of limiting and containing the threat to health represented by bacterial resistance, the Argentine government recently regulated the Antimicrobial Resistance Prevention and Control Law. With the purpose of promoting their responsible use, both in human and animal health, the regulation establishes, among other things, that they can only be sold under a filed prescription, in sufficient quantity for the complete treatment and in a single container. (Source: CyTA-Leloir Agency)
#prevent #bacteria #resistant #antibiotics #delay #happening