Studies Resistant bacteria are more aggressive and contagious

Study: Antibiotic resistance makes bacteria even more aggressive
According to current knowledge, experts assumed that bacteria that are resistant to antibiotics are rather weakened. However, a new US study now proves the opposite. Thus, resistant pathogens are even more aggressive and contagious than bacteria without antibiotic resistance.

Antibiotics Resistant bacteria are a global problem
As the researchers around Gerald Pier and David Skurnik from the Harvard Medical School in Boston, Massachusetts in the journal "Science Translational Medicine" report, resistant bacteria are more dangerous than previously thought. The fight against resistance is becoming more difficult.

Much more aggressive and highly contagious: Resistant germs. Image: Sebastian Kaulitzki - fotolia

Antibiotic resistance, among other things, is a consequence of the frequent use of the drugs in medicine and animal breeding, especially in factory farming. For years, experts worldwide have been warning of the problem. Because more and more antibiotics are ineffective for certain bacteria. Special critics rate the use of so-called broadband antibiotics, which at the same time can fight several bacteria strains, but unfortunately can also make them resistant. Antibiotics have long been considered a miracle weapon in the fight against infections. It is questionable how inflammations will be combated without the usual antibiotics in the future. Researchers around the world are working on alternative means. Among other things, Swiss scientists recorded their first successes last year. They developed nanoparticles that do not eliminate the bacteria themselves, only their poison. Resistances do not arise. So far, however, the new substance has only been tested on mice. Whether it is effective in humans, must be clarified in further studies.

Antibiotic-resistant bacteria are more active than expected
It will be some time before an antibiotic alternative is available. Until then, not only the problem of resistance itself arises. According to the new study, antibiotic-resistant pathogens are more dangerous than previously thought.

Pier and Skurnik wanted to find out if resistant bacterial strains are actually less active than their antibiotic-sensitive relatives, as is common wisdom. To do this, they performed their experiments with three pathogens on mice: Pseudomonas aeruginosa, a common cause of pneumonia, Vibrio cholerae, the causative agent of cholera, and Acinetobacter baumannii, a frequent trigger of hospital infections. As it turned out, the three resistant pathogens were more easily transmitted and more aggressive.

"Our results show consistently for each of these very different pathogens that resistance and the acquisition of new resistance to promote fitness and survival in an infected host," quotes the news agency "dpa" the study authors. This is related to the good defense beyond the contact with antibiotics, which makes them more viable. Microorganisms are permanently confronted with poisons of other pathogens or immune system defenses. "Together, these findings warn that combating antibiotic resistance may be more difficult than we thought due to the improved fitness and virility of our antibiotic-resistant adversaries," write Pier and his colleagues in the journal.

Resistant bacteria could cause serious infections
"The increased aggressiveness of resistant strains in trials raises the serious concern that these can cause more difficult to treat infections, even beyond antibiotic therapy," the authors said. The absence of antibiotics alone is not enough to stem the development and spread of resistant pathogen strains. Alternatives would be needed to prevent and treat infections.

Helmut Fickenscher from Kiel University spoke to the news agency about a "very, very exciting study". The researchers had gone very detailed in their work. "Whether that will revolutionize medicine, however, is completely open." According to the physician, the question arises whether the results of animal studies on humans are transferable. However, he rates the study results as quite plausible. Because the genes for antibiotic resistance and high aggressiveness would often be transmitted together, which could explain an increased aggressiveness of multidrug-resistant microorganisms. (Ag)