What Doesn’t kill Them Makes Them Stronger

By Nick Gubitosi         February 13, 2010

This past Thursday, a group of scientists from Boston University released a new study which revealed that treating bacteria with low levels of antibiotics produces mutations in the bacteria instead of killing them, allowing them to gain resistance to a wide range of antibiotics.  This newly gained understanding for the biomolecular processes that produce these “superbugs” can lead to the development of new antibiotics or even enhanced treatments that could prevent the creation of these extremely dangerous cross-resistant bacteria.

The team of scientists led by Professor James Collins, performed their tests on strains of E. coli and Staphylococcus.  They started by administering low levels of five different antibiotics to the bacteria, which caused the introduction of mutations into the bacterial DNA.  They followed this by then giving lethal doses of antibiotics to these mutated bacteria.  The results revealed that many of the bacteria initially exposed to low levels of antibiotics now exhibited cross-resistance to a variety of antibiotics.

In lethal levels, antibiotics cause bacterial DNA to be shredded.  However, when the antibiotic is not at a lethal level, mutations are entered into the bacterial DNA instead.  The bacteria not only survive with these mutations, but gain protection from antibiotics including ones that the bacteria weren’t even exposed to.

This study helps to show the serious dangers involved with taking low or incomplete doses of antibiotics, which is common practice in many areas today.  Farmers who include antibiotics in their livestock feed, doctors who prescribe antibiotics at random, and patients who don’t follow their full course of drugs are all promoting the creation of these bacterial “superbugs.”

With the information gained from these findings, enhanced antibiotic treatments can be developed that could prevent the emergence of multi-drug resistant bacteria and even increase their DNA killing ability so that low doses of antibiotics would be enough to kill mutated bacterial cells.

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