Chemicals used in the environment to kill bacteria could be making them stronger, according to a paper published in Microbiology. Low levels of these chemicals, called biocides, can make the potentially lethal bacterium Staphylococcus aureus remove toxic chemicals from the cell even more efficiently, potentially making it resistant to being killed by some antibiotics.
Biocides are used in disinfectants and antiseptics to kill microbes. They are commonly used in cleaning hospitals and home environments, sterilizing medical equipment and decontaminating skin before surgery. At the correct strength, biocides kill bacteria and other microbes. However, if lower levels are used the bacteria can survive and become resistant to treatment.
"Bacteria like Staphylococcus aureus make proteins that pump many different toxic chemicals out of the cell to interfere with their antibacterial effects," said Dr Glenn Kaatz from the Department of Veterans Affairs Medical Center in Detroit, USA. "These efflux pumps can remove antibiotics from the cell and have been shown to make bacteria resistant to those drugs. We wanted to find out if exposure to biocides could also make bacteria resistant to being killed by the action of efflux pumps."
The researchers exposed S. aureus taken from the blood of patients to low concentrations of several biocides and dyes, which are also used frequently in hospitals. They looked at the effect of exposure on the bacteria and found that mutants that make more efflux pumps than normal were produced.
"We found that exposure to low concentrations of a variety of biocides and dyes resulted in the appearance of resistant mutants," said Dr Kaatz. "The number of efflux pumps in the bacteria increased. Because the efflux pumps can also rid the cell of some antibiotics, pathogenic bacteria with more pumps are a threat to patients as they could be more resistant to treatment."
If bacteria that live in protected environments are exposed to biocides repeatedly, for example during cleaning, they can build up resistance to disinfectants and antibiotics. Such bacteria have been shown to contribute to hospital-acquired infections.
"Scientists are trying to develop inhibitors of efflux pumps. Effective inhibitors would reduce the likelihood of additional resistance
mechanisms emerging in bacteria," said Dr Kaatz. "Unfortunately, inhibitors evaluated to date do not work on a wide range of pathogens so they are not ideal to prevent resistance."
"Careful use of antibiotics and the use of biocides that are not known to be recognised by efflux pumps may reduce the frequency at which resistant strains are found," said Dr Kaatz. "Alternatively, the combination of a pump inhibitor with an antimicrobial agent or biocide will reduce the emergence of such strains and their clinical impact."
Article: "Multidrug efflux pump overexpression in Staphylococcus aureus after single and multiple in vitro exposures to biocides and dyes", October 2008 Microbiology.
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- Will Aspartame Critics Now Be Less Bitter?
- New Results From The LHC At 13 TeV!
- New Ice Age Is Coming, By 2030, Says Analysis
- Grasping How The Brain Plans Gripping Motion
- Kepler 452b - Things That Could Go Wrong With Habitability & If It Is - Could We Detect Intelligent Life There?
- Michelangelo Likely Used Mathematics When Painting The Creation Of Adam
- An Anti-Aging Pill Is Still A Long Way Off
- "There are two zero-entries data points not shown (semi-log graph).Nobody gets excited by two events..."
- "That was a pun! Excesses usually appear toward the end of a spectrum... and the energy being 1..."
- "I'm not so sure about the point on the generic drug manufacturers abandoning a generic once it..."
- "Reproduction studies need some way to get published, and then somehow, some mechanism needs to..."
- "Hi T, Thanks for the note. Great LHC is back in business and your summary helps us get up to date!..."