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细菌也有“懒汉”对付耐药菌或可不靠抗生素

作者:
英国诺丁汉大学9月6日发表公报说,该校研究人员发现细菌中存在一些“好吃懒做者”,它们的存在会减弱整个菌群的致病性。研究人员认为可以利用这些“懒汉”细菌帮助治疗疾病。

  研究人员发现在致病性葡萄球菌中存在这样一些“懒汉”细菌。通常葡萄球菌会通过分泌毒素来造成感染,并从受感染的机体中获得营养物质,但有一些葡萄球菌发生变异后就不怎么出力分泌毒素,而是利用其他细菌的感染能力来获取食物,它们这样做的好处就是可以有更多精力繁殖后代。

  研究人员发现,由于不劳而获,“懒汉”细菌的数量很快就超过那些努力分泌毒素细菌的数量,结果整个菌群的感染能力下降。

  参与研究的埃里克·波利特(Eric Pollitt)说,为验证这个想法,他们让这些细菌感染了一些虫子,结果发现“懒汉”细菌不仅逐渐在自己的菌群中数量占优,还会去“入侵”其他的菌群。这说明的确存在用“懒汉”细菌治病的可能性,并且这种疗法不依靠抗生素,将来可能是对付现在许多抗药性细菌的一种新选择。

  波利特在英国普通微生物学会(Society for General Microbiology)当天举行的学术会议上提出了这项发现。

Backstabbing bacteria: a new treatment for infection?

06 Sep 2010 12:00:00.00

Selfish bacterial cells that act in their own interests and do not cooperate with their infection-causing colleagues can actually reduce the severity of infection.

The selfish behaviour of these uncooperative bacteria could offer a new hope in the future fight against antibiotic resistant infections such as MRSA, according to a study carried out by researchers at The University of Nottingham.

Bacteria work together by using a well-studied communication system called Quorum Sensing (QS). During infection, bacteria talk to each other using QS to coordinate the release of toxins.

Researchers at the University, led by Dr Steve Diggle in the Centre for Biomolecular Sciences, have discovered that in Staphylococcus aureus infections, bacteria defective in QS can benefit from 'opting out' of toxin production. By doing so, they can invest more energy in reproducing - while taking advantage of the nutrient-rich infection maintained by their neighbours.

By looking after themselves in this way, QS-deficient bacteria are quickly able to outnumber other bacteria that are busy making toxins. As a result, the overall severity of infection is reduced as fewer toxins are produced.

"This opens up the interesting possibility of using these uncooperative bacteria to treat infection," said PhD student Eric Pollitt, who conducted the experimental work for the research and will present a paper on the study at the Society for General Microbiology's autumn meeting today (Sept 6).

The Nottingham group tested the theory by introducing S.aureus into waxworms that subsequently developed infections.

"We found that the QS-deficient bacteria could not only outgrow normal bacteria in the same population, but that they could also invade other cooperating populations to reduce the severity of infection. This means that we could potentially isolate QS-deficient bacteria and use them to treat clinical S.aureus infections," he added.

New approaches for the treatment of S.aureus infections are desperately needed as many strains of the bacterium such as Methicillin-resistant Staphylococcus aureus (MRSA) are resistant to antibiotics. "Importantly, as any treatment involving QS-deficient bacteria would not be based on antibiotics, it could complement current treatments for S.aureus infections," said Mr Pollitt.

Using bacteria to treat bacterial infections is a potentially useful, yet paradoxical approach. "It's an interesting concept of 'fighting like with like'", suggested Mr Pollitt. "This work highlights that the interactions between bacteria during an infection can be just as important as the interactions between the bacteria and the host."