When a bacterial population is placed under a stressor — such as an antibacterial chemical — a small subpopulation armed with special defense mechanisms can develop. New lines of bacteria survive and reproduce as their weaker relatives perish.
Scientific American reports that antibacterial products may increase our risks,
Traditionally, people washed bacteria from their bodies and homes using soap and hot water, alcohol, chlorine bleach or hydrogen peroxide. These substances act nonspecifically, meaning they wipe out almost every type of microbe in sight—fungi, bacteria and some viruses—rather than singling out a particular variety.
Soap works by loosening and lifting dirt, oil and microbes from surfaces so they can be easily rinsed away with water, whereas general cleaners such as alcohol inflict sweeping damage to cells by demolishing key structures, then evaporate. “They do their job and are quickly dissipated into the environment,” explains microbiologist Stuart Levy of Tufts University School of Medicine.
Unlike these traditional cleaners, antibacterial products leave surface residues, creating conditions that may foster the development of resistant bacteria. After spraying and wiping an antibacterial cleaner over a kitchen counter, active chemicals linger behind and continue to kill bacteria, but not necessarily all of them.
As bacteria develop a tolerance for these compounds there is potential for also developing a tolerance for certain antibiotics. This phenomenon, called cross-resistance, has already been demonstrated in several laboratory studies using triclosan, one of the most common chemicals found in antibacterial hand cleaners, dishwashing liquids and other wash products.
For additional worry, please note:
Antibacterial compounds, triclosan and its close chemical relative triclocarban, are present in 60 percent of America’s streams and rivers.