The Growth of Superbugs
Reported January 05, 2010
(Ivanhoe Newswire) — Using disinfectants could cause bacteria to become resistant to antibiotics as well as the disinfectant itself, according to new research.
Researchers from the National University of Ireland in Galway found that by adding increasing amounts of disinfectant to laboratory cultures of Pseudomonas aeruginosa, the bacteria could adapt to survive not only the disinfectant but also the commonly-prescribed antibiotic ciprofloxacin — even without being exposed to it.
Disinfectants are used to kill bacteria on surfaces to prevent their spread. If the bacteria manage to survive and go on to infect patients, antibiotics are used to treat them. Bacteria that can resist both these control points pose a serious threat to hospital patients.
P. aeruginosa is an opportunistic bacterium that can cause a wide range of infections in people with weak immune systems and in those with diseases such as cystic fibrosis and diabetes. P. aeruginosa is an important cause of hospital-acquired infections.
The researchers showed that the bacteria in culture adapted to more efficiently pump out antimicrobial agents from the bacterial cell. The adapted bacteria also had a mutation in their DNA that allowed them to resist ciprofloxacin-type antibiotics specifically.
Importantly, the study showed that when very small non-lethal amounts of disinfectant were added to the bacteria in culture, the adapted bacteria were more likely to survive.
Study leader Dr. Gerard Fleming was quoted as saying, “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 defense against hospital-acquired infections.”
SOURCE: Microbiology, January, 2010