September 2006 Burns Victims and Cystic Fibrosis Sufferers could

Burns victims and cystic fibrosis sufferers could benefit from the latest research into hyper-resistant bacteria, often known as superbugs, at NUI Galway. The research, carried out by postgraduate Paul Mc Cay under the supervision of Dr Ger Fleming of NUI Galway's Microbiology Department, looked at the cross-resistance of a particular strain of bacteria to both antibiotics and disinfectant.

The three-year study focused on Pseudomonas aeruginosa, an opportunistic pathogen often associated with burn wound sepsis or sufferers of cystic fibrosis and is frequently connected with hospital acquired pneumonia. The University team developed a highly resistant strain of the bacteria and mixed it with the original strain, and a very low level of either antibiotic or disinfectant.

The research found that when low levels of antibiotic or disinfectant were present, the ordinary strain of the bacteria was significantly disadvantaged and the superbugs became dominant. The superbugs were also found to be more readily resistant to other types of antibiotic or disinfectant when they were subsequently introduced. Furthermore, superbugs with antibiotic resistance also had resistance to disinfectant, even though the disinfectant had never been present, suggesting a strong link between the development of resistance to antibiotics and disinfectant.

"This could have major implications for those administering antibiotics. Firstly, for burn victims and cystic fibrosis sufferers, infections can be long-term. While treatment with antibiotics is the obvious solution this approach is sometimes quite broad and if one antibiotic does not work, we switch to another. However, we may in fact be selecting for resistance and developing an even stronger pathogen. Secondly, disinfectant - tolerant bacteria are emerging more often and this may contribute to antibiotic cross resistance", commented Dr. Fleming.

With funding from Research Frontiers Programme, administered by SFI, and the Embark initiative, Paul Mc Cay is one of only a few researchers in Ireland or Britain that utilises long-term selective chemostat cultures for investigations. Using a chemostat culture system, which mimics a natural environment, a highly resistant strain of the bacteria can be grown and in theory grow indefinitely. This better mimics how bacteria behave in the natural environment while allowing bacteria to mutate, evolve and "adapt" to selective agents such as antibiotics and disinfectants.

Dr. Fleming and Mr. Paul Mc Cay presented their work at the Society for General Microbiology's 159th meeting, in York on Wednesday 13 September 2006.

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