“Hospitals have been warned not to over-dilute cleaning chemicals amid fears that this could boost antibiotic resistance in bacteria” says the BBC News website today. A study in the US found that exposing the bacteria Staphylococcus aureus to low concentrations of a wide range of antiseptic and antibacterial solutions lead to the formation of strains that had “a higher number of ‘efflux pumps’, a feature found on the surface of their cells which allows them to get rid of toxic molecules”, the website says. These pumps can also remove certain antibiotics, such as ciprofloxacin, from the bacteria.
This study did show that there was a possibility of increasing “efflux pump” levels after exposure to low levels of certain cleaning chemicals (disinfectants and antiseptics known as biocides) and dyes. However, it did not investigate directly whether this has been responsible for the development of either antibiotic- or biocide-resistant bacteria in hospitals. Unlike antibiotics, biocides can be used in very high concentrations, and the findings of this study suggest it may be important to use sufficiently high concentrations of cleaning products. Further research into whether different kinds of cleaning products or ways of using them could avoid this potential source of antibiotic-resistant bacteria is warranted.