Hospital disinfectants created drug-resistant Acinetobacter strains
DENVER — Exposure to disinfectants can lead to resistant isolates of Acinetobacter spp. in hospitals, researchers reported here at the 2013 Interscience Conference on Antimicrobial Agents and Chemotherapy.
“We wanted to see if the proven method of disinfectant is capable of eliminating the threat of Acinetobacter in hospitals,” Charalampos Tsoukalas, a PhD student at Nottingham Trent University in the United Kingdom, told Infectious Disease News. “We found that the commonly used disinfectants cannot always eliminate the entire threat, and they can actually produce resistant isolates that are resistant to other disinfectants and cross-resistant to other antibiotics.”
Tsoukalas and colleagues cultured 43 Acinetobacter spp. strains in increasing concentrations of two disinfectants: Trigene and Hycolin. Thirteen of the strains developed resistance to Trigene and three developed resistance to Hycolin. The researchers examined these resistant strains for cross-resistance to polymyxin B. They also examined all 43 of the Acinetobacter strains to analyze genetic distance.
They found that seven of the strains that were resistant to Trigene were also resistant to polymyxin B, and there was a genetic link between the resistant strains; namely. In addition, one efflux pump system for the Acinetobacter spp., AdeABC, is involved in resistance. In the resistant strains, there were also altered virulence factors, namely the ability of the strains to translocate through differentiated human lung cell membranes in vitro was increased. According to Tsoukalas, this means that the resistant isolates can potentially be more pathogenic than the natural ones.
“It is important to understand the mechanisms of resistance of bacteria and also to find ways to bypass them,” Tsoukalas said. “Our study suggests a need to change disinfectants regularly and, if possible, use two or three different disinfectants to make sure that there will be no surviving bacteria.”
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Disclosure: Tsoukalas reports no relevant financial disclosures.