耐药细菌 z-bo 2020-09-19 416

　　A new study shows that bacteria that are resistant to antibiotics may be more tenacious than we previously thought. Not only are these bacteria difficult to treat, they also seem to be more "adapted" in the general sense, which means they can survive better in the host and cause more deadly infections.

　　These findings are contrary to the prevailing view in the medical field. Traditional views believe that when bacteria acquire resistance, they become less "adapted" to some extent, for example, their ability to spread will be weakened. Although scientists usually assume that this view is true, the evidence to support this view is actually very limited, the researchers said.

　　In the new study, the researchers tested the effect of drug resistance genes on Pseudomonas aeruginosa. This bacteria can cause lung infections.

　　They found that during the research phase, mice infected with antibiotic-resistant Pseudomonas aeruginosa were more likely to die than mice infected with non-resistant Pseudomonas aeruginosa (without any kind of treatment).

　　Antibiotic-resistant strains are also better at killing certain types of immune cells (the cells in the human body that defend against bacteria and other pathogens).

　　"We may have overlooked another result of the pathogen's acquisition of drug resistance, that is, this may also enhance the adaptability and virulence of the pathogen," a researcher from Brigham and Women's Hospital in Boston wrote in Science Translational Medicine. (Science Translational Medicine) pointed out in an article in the journal. This discovery "raises a serious problem. In addition to increasing the complexity of antibiotic treatments, drug-resistant strains may be more adaptable and therefore can cause serious and more difficult-to-curable infections," they said.

　　Researchers also found similar phenomena in two other bacteria: Acinetobacter baumannii, which causes infections in hospitalized patients, and Vibriocholera, which causes diarrhea and cholera. For example, Vibrio cholerae with specific antibiotic resistance genes can grow in the gastrointestinal tract of rabbits better than bacteria without these genes.

　　"Our results show that efforts to cope with the worldwide increase in antibiotic resistance may be hindered by the increased adaptability of resistant bacteria. This adaptability enhances the virulence of bacteria." The researchers wrote.

　　Research findings also “emphasize the need to effectively control the emergence of drug-resistant pathogens and the need to develop alternative methods to prevent and treat infections,” they wrote.

　　Infectious disease expert and senior associate dean of the University of Pittsburgh Center for Medicine and Health Safety, Dr. Amesh Adalja, said the new findings are not entirely unexpected. This is because the mutations that make bacteria resistant to certain antibiotics also have other effects, including enhancing the viability of bacteria. "This is not a simple balance of interests." Adalja said, he did not participate in the study. Acquiring resistance does not necessarily sacrifice survivability.

　　Adalja also mentioned that researchers found bacteria resistant to many antibiotics in the cave, even if these bacteria have never been in contact with humans, they have never been treated with antibiotics. Bacteria may have evolved these resistance genes long ago to protect themselves from other bacteria or to help them survive in other ways, Adalja said.

　　"Antibiotic resistance is not a new characteristic created after the discovery of penicillin," Adalja said.

　　Research shows that there may always be some degree of antibiotic resistance, even if doctors improve the way they use antibiotics. "Antibiotic managers can do only a limited amount," Adalja said.

　　This means that to prevent the spread of antibiotic resistance, it is not just the scientific use of antibiotics, Adalja said. Researchers need to develop treatments and prevention methods that are different from antibiotics, such as drugs or new vaccines that target specific bacterial toxins, Adalja said.