Disinfectants could promote growth of superbugs, say researchers
Using disinfectants could cause bacteria to become resistant to antibiotics as well as to the disinfectant itself, according to research published in the January issue of Microbiology.¹
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 ciprofloxacin – a commonly-prescribed antibiotic – even without being exposed to it. The researchers showed that the bacteria had adapted more efficiently to pump out antimicrobial agents (disinfectant and antibiotic) from the bacterial cell. The adapted bacteria also had a mutation in their DNA that allowed them to resist ciprofloxacin-type antibiotics specifically.
Pseudomonas aeruginosa is an important cause of hospital-acquired infections and can cause a wide range of infections in people with weak immune systems and those with diseases such as cystic fibrosis (CF) and diabetes. The research findings could therefore have important implications for how the spread of infection is managed in hospital settings. Significantly, 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 compared with the non-adapted bacteria. “In principle this means that residue from incorrectly diluted disinfectants left on hospital surfaces could promote the growth of antibiotic-resistant bacteria,” said Dr Gerard Fleming, who led the study. “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.
Reference: 1. P. H. Mc Cay, A. A. Ocampo-Sosa and G. T. A. Fleming; Microbiology ; 156: 30-38
Contact Dr Gerard Fleming T +35 385 144 9751 {encode="ger.fleming@nuigalway.ie" title="ger.fleming@nuigalway.ie"}
The Society for General Microbiology www.sgm.ac.uk/pubs
