Misuse of Antibiotics May Spur Bacterial Acquisition of Drug Resistance

A recent paper reviewed the scientific literature regarding acquisition of drug resistance by bacteria and advanced the theory that in most cases resistance is transferred by uptake of DNA that had been released by resistant organisms that had been broken open by the stress of antibiotic treatment.

The author, Dr. Mohammed Bakkali, professor of genetics at the University of Granada (Spain) reviewed some of the literature on bacterial acquisition of drug resistance and discussed four hypotheses on how and why bacteria take up DNA. He argued in the February 5, 2013, online edition of the journal Archives of Microbiology that DNA uptake by bacteria is an accidental by-product of bacterial adhesion and twitching motility. Adhesion and motility are generally increased in stressful conditions, which may explain why bacteria increase DNA uptake in these conditions.

This hypothesis has significant clinical implications and finds further support from the fact that antibiotics sometimes fail to eliminate the targeted bacterium while inevitably causing stress to others. The widespread misuse of antibiotics may thus not only be selecting for resistant strains, but may also be causing bacteria to take up more DNA with the consequent increase in the chances of acquiring drug resistance and virulence.

"Our current indiscriminate use of antibiotics not only selects the resistant bacteria, but also means that the bacteria take up more DNA, due to their increased motility in response to the stress that the antibiotic subjects them to," said Dr. Bakkali. "In this way, the nonresistant bacteria become resistant completely by accident on ingesting this DNA and can even become much more virulent, partly due to the stress we subject them to when we make an abusive use of antibiotics."

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University of Granada