Peculiar 'sex' makes bacteria antibiotic resistant

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Washington, June 12 (ANI): The reason why some bacteria are becoming resistant to antibiotics can be attributed to their peculiar sex lives, according to a new study.

Reported in the journal Science, the study from Imperial College London may further scientists' understanding as to how bacteria develop resistance to antibiotics, which is a major challenge for those treating infectious diseases.

It looks at bacteria called pneumococcus (Streptococcus pneumoniae), which cause diseases like pneumonia and bacterial meningitis.

Pneumococcal infections cause approximately one million deaths every year globally. Their treatment is increasingly becoming difficult because the bacteria are developing resistance to many antibiotics.

The scientists behind the current study believe that this resistance is due to the pneumococcal bacteria adapting by occasionally picking up DNA from other bacteria, even from other species.

Dr. William Hanage, the lead author of the study from Imperial College London, said: "Bacteria have very peculiar sex lives. When humans have kids they mix up their DNA with that of their partner, but bacteria can pick up DNA from all sorts of places, even other species. Our research shows that bacteria which do this, that is undergo sex, with their own and other species are more likely to develop resistance to antibiotics, protecting them from being killed by these drugs."

He points out that bacteria reproduce asexually by splitting in two to produce identical 'daughter' cells. However, they sometimes can take up DNA from other bacteria or the environment, and incorporate it into their own genome in a process called recombination.

Though this mixing process is most common between bacteria of the same species, bacteria can sometimes undergo recombination with different species of bacteria, which means that the daughter cells end up with DNA from those species.

Dr. Hanage says that some combinations of DNA help bacteria to survive better.

According to him, antibiotic resistant strains of pneumococcus are more likely to mix up their DNA in this way, and so are more likely to hit upon the adaptation which helps them resist antibiotic treatment.

He said: "Antibiotic resistance is a growing problem, particularly for potentially dangerous pneumococcal infections. Our new findings help us to understand how bacteria can wriggle their way out of tight spaces, finding ways to evade the drugs we bombard them with. Ultimately, we hope that we could use this knowledge to limit the emergence of new types of antibiotic resistance."

For this research, Dr. Hanage examined DNA from 1,930 different S. pneumoniae strains and three closely related species-namely, S. mitis, S. pseudopneumoniae and S. oralis.

He and his colleagues were able to find strains with DNA, which suggested recombination.

Comparing their findings with data on resistance to the commonly-used antibiotics penicillin, erythromycin, tetracycline, chloramphenicol and cefotaxime, the researchers came to the conclusion that bacteria with mixed DNA were more likely to be resistant to antibiotics, suggesting a link between recombination and antibiotic resistance. (ANI)

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