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?
- Today's Global Warming Is Nothing Special
- Conservation Of Massive: When You Lose Weight, Where Does The Fat Go?
- New Limits On VY Production From CDF: Good, But Also Disappointing
- There Was No 'Paleo Diet' - Ancient People Ate What They Had
- To Be Cool Kids, Are We Programmed To Make Bad Decisions?
- Physics is too hard for women, according to female physics students
- Silica-Based Carbon-trapping 'Sponges' Can Cut Greenhouse Gases
- "Though high-profile tragedies get mainstream media attention, the gun ban contingent has lost a..."
- "The wording of the article makes one wonder if there is not a political motivation. You would think..."
- "it took 200,000 years for the climate to return to normal Define normal...."
- "Another article today reports that electricity, in New England, has jumped to 24 cents/ KWHr. A..."
- The Lancet: World population gains more than 6 years of life expectancy since 1990
- Big data may be fashion industry's next must-have accessory
- Weigh-in once a week or you'll gain weight
- Targeted next-generation sequencing reveals a high number of genomic mutations in advanced malignant
- A survey of the general population in France identifies knowledge gaps in the perception of lung cancer