Researchers from the National University of Ireland in Galway have found that adding increasing amounts of disinfectant to cultures of the bacteria Pseudomonas aeruginosa resulted in the bacteria adapting in ways to survive the disinfectant itself - no real surprise there. However, the researchers also discovered that the disinfectant exposed bacteria had also developed resistance to a commonly used antibiotic known as ciprofloxacin, without

ever being exposed to it - causing alarm that the use of such disinfectants in a hospital setting could be promoting the growth of 'Superbugs'.

The team demonstrated that the bacteria had adapted to more efficiently pump out antimicrobial agents from the cell - both disinfectant, and antibiotic. It was also discovered that the adapted bacteria contained a mutation in their DNA that yielded resistance to ciprofloxacin-type antibiotics specifically.

Dr. Gerard Fleming, who led the study, said, "In principle this means that residue from incorrectly diluted disinfectants left on hospital surfaces could promote the growth of antibiotic-resistant bacteria. What is more worrying is that bacteria seem to be able to adapt to resist antibiotics without even being exposed to them."

Dr. Fleming also stressed the importance of studying the environmental factors that might promote antibiotic resistance. "We need to investigate the effects of using more than one type of disinfectant on promoting antibiotic-resistant strains. This will increase the effectiveness of both our first and second lines of defence against hospital-acquired infections," he said.

The research is to be published in the January issue of Microbiology.

Source: http://www.nuigalway.ie/microbiology/news.html