Apply the disinfectant, kill the germs — right? Not necessarily.
With the advent of modern disinfectants, many of us may feel a false sense of security when using germicides. Why?
Scientists are finding germs are apparently smarter, tougher and more organized than anyone ever imagined. Recent discoveries have shown that bacteria on damp surfaces do not remain as isolated and free floating life forms but communicate and colonize with other germs to build a tough, protective biofilm that can withstand even the strongest disinfectants.
Scientific American Magazine reports that bacteria communicate to build “microcolonies within a sophisticated architecture” that protects the organisms in a kind of walled — if somewhat slimy — city.
According to Science News Magazine, scientists report that, “Pseudomonas [the bacterium that causes cystic fibrosis pneumonia] … [in a biofilm can] survive in bottled iodine solution for up to 15 months.” Based on another study, Scientific American reported that harmful microbes suspended in a biofilm were still alive and well after 60 minutes exposure to bleach.
Stanford University researchers reported that the germ that causes cholera (Vibrio cholerae) forms a biofilm that enables it to survive in the presence of chlorine in concentrations 1000 to 2000% higher than that found in chlorinated drinking water. Washington DC’s water supply was compromised by biofilms in 1996 for this very reason.
Ironically, bacterial biofilms can even colonize biomedical products. Scientific American reports that in 1993, 100 asthmatics died because their inhalants contained Pseudomonas aeruginosa that had formed a biofilm in the tank involved in manufacturing the inhalant. In 1989, bacterium P. cepacia colonized inside of an iodine-based antiseptic solution, causing infections in a Texas children’s hospital.
Where else are biofilms likely to form and what can you do about them? Bacteria and other microbes require a damp surface to form a biofilm. In our mouths, the biofilm is called plaque. Biofilms are also often found in places such as inside water distribution pipes, in kitchens, and notably, under the rims of toilets and urinals.
According to researchers J. W. Costerton and Philip S. Stewart, writing in Scientific American Magazine: “bacterial biofilms are ubiquitous … the slippery coating on a rock in a stream, and the slime that inevitably materializes inside a flower vase after two or three days are but a few common examples.”
Weapons Against Biofilm
Obviously, just applying your favorite disinfectant (even full-strength) may not remove a biofilm colony. What’s needed?
Since the disinfecting or sanitizing agent must be able to access or get to the germs embedded in the biofilm “matrix” that makes up two-thirds of the biofilm, the matrix must be broken down before the germs are vulnerable. Therefore, one method is brushing or agitation of the surface.
Therefore, a bowl brush can be an important ‘disinfecting’ tool when used beneath the rim of toilet bowls and urinals. The biofilm must be physically broken up by the bowl brush before the flushing action of the toilet can remove the microbes.