Recent research has shown that antimicrobial compounds used in a wide range of soaps and toothpastes can increase the risk of infection, alter the gut microbiome and help to breed antibiotic-resistant bacteria.
. These common agents such as triclosan and triclocarban are useful in hospitals, and can kill off bacteria when used as part of a long wash, but are no more effective than normal soap during a 30-second wash in warm water.
New studies have shown that exposure to triclosan, which easily enters the body through ingestion and absorption, can make it harder for your body to resist the Staphylococcus aureus bacteria, while triclocarban, used in some bar soaps, has been found to alter the microbiomes of mother and baby rats in studies.
There are specific circumstances in which those antimicrobials can be useful, civil engineer Patrick McNamara of Marquette University in Milwaukee says,it may be useful to doctors scrubbing for minutes at a time before a surgery or for hospital patients who can’t necessarily scrub with soap but could soak in a chemical bath.
Triclosan and triclocarban kill off bacteria only during long washes, but most people only clean their hands for a few seconds. There’s evidence that there is no improvement with using soaps that have these chemicals relative to washing your hands under warm water for 30 seconds with soaps without these chemicals.
In the meantime, researchers seem to be digging up more and more dirt on the chemicals, particularly triclosan. These antimicrobials are widely used not just hand soaps, but body washes, shampoos, toothpastes, cosmetics, household cleaners, medical equipment, and more. it’s just as pervasive in people as it is in homes and clinics.
Triclosan easily enters bodies by ingestion (think toothpaste) or skin absorption. It’s commonly found in people’s urine, blood and breast milk.
Microbiologist Thomas Sharpton of Oregon State University and his colleagues are currently studying triclosan’s effect on the gut microbiomes of zebra fish, a model organism for vertebrate development. The preliminary data suggest that the antimicrobial causes swift, sweeping changes in the zebra fish gut microbiome, altering both diversity and community structure.
In a 2014 study, McNamara’s research team found that triclosan messed with the microbial communities that break down sewage, in some cases sabotaging their ability to digest the sludge.
The chemical also caused a spike in the presence of a gene called mexB in the sewage microbes. This gene codes for a pump that allows bacteria to simply kick out triclosan before it can kill them off. This pump, McNamara hypothesizes, also spits out common prescription antibiotics, such as ciprofloxacin. In experiments, bacteria with mexB were resistant to antibiotics.
In a January study, McNamara, his graduate student Daniel Carey, and colleagues found that triclocarban had the same effect as triclosan—it also disrupts the microbial communities that digest sewage and spurs bacteria to become resistant to drugs.
The waste water treatment plants can be a source of these superbugs can leak out into waterways, wildlife, and potentially back to people.
read more http://arstechnica.com/science/2016/04/mounting-data-suggest-antibacterial-soaps-do-more-harm-than-good/
