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Disinfectant misuse could help create superbugs

December 29, 2009 |  3:05 pm
Pseudomonas aeruginosa: A drug-resistant form of a bacterium usually associated with hospital-acquired infections led to the death of Brazilian beauty queen Mariana Bridi Disinfectants may be a double-edged sword in the fight against hospital-borne diseases, scientists say. 

According to a study to be published in January’s issue of Microbiology, researchers from the National University of Ireland in Galway slowly introduced higher levels of disinfectant to lab cultures of Pseudomonas aeruginosa, which lives in the soil and water around us. It can’t seriously hurt healthy people (it’s been implicated in “hot tub itch” and “swimmer’s ear”) but preys on those with compromised immune systems. This opportunistic pathogen can infect the lungs, joints, burn wounds, take advantage of a compromised urinary tract or cause blood diseases. The bacterium can live in man-made environments and colonize catheters and other medical equipment. It’s ideally suited for hospital transmission – the Online Textbook of Bacteriology calls it “the fourth most commonly-isolated nosocomial pathogen accounting for 10.1 percent of all hospital-acquired infections” – but it can infect anyone whose defenses have been weakened, whether from chemotherapy or diabetes, cystic fibrosis or AIDS. 

After gradually upping the dose of benzalkonium chloride, an antiseptic used in products that include eyedrops and wet wipes, researchers had on their hands a Frankensteinian pathogen that showed a 12-fold resistance to the common disinfectant. (Generally, showing four or five times the normal resistance level is enough to earn a newer, nastier disease “superbug” status.)

Even worse, that same variant of P. aeruginosadisplayed a whopping 256-fold increase in resistance to the antibiotic ciprofloxacin – even though it had never been exposed to the drug before. That’s worrisome, since the commonly prescribed Cipro has been used to treat such high-profile pathogens as anthrax spores.

The upshot? That hospitals that don’t use enough disinfectant to kill every last bacterium on a given surface could provide an ideal breeding ground for new superbugs. These mutations could become virtually immune to prevention and treatment.

“The message, for heaven’s sake, is use disinfectants properly,” lead author Gerard Fleming said in an interview. “The first line of defense is disinfection. The second line of defense is antibiotics.”

By misusing disinfectants, he concluded, “You're making an environment where you've now lost the first and second lines of defense.”

There’s a dangerous tendency toward using disinfectants as a clean-all, Fleming said, when there was a much more potent, proven remedy to rid oneself of germs.

“Soap and water. I am not messing with you,” Fleming said. “Why doesn’t the surgeon, when he’s going into the theater, just take a hand sanitizer? Why does he go to the sink and scrub and scrub and scrub? Because he’s physically removing the bacteria.”

-- Amina Khan

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Comments (4)

We live in a society of manufactured fear where advertisers hype a fear to sell disinfectants, mouthwash, cleaning products and everything else under the sun designed to give you, The Consumer, peace of mind from the fears that have been encouraged in you. Fear of germs incapacitated the brave and intelligent Howard Hughes, and it has turned us into a nation of Lysol-spraying paranoids.

True the surgeon scrubs to remove bacteria, however they use a product such as Hibicleanse which uses a germicidal ingredient. The instructions state to apply product and to make sure 100% of the bacteria is gone it states to scrub the whole hand especially the fingernails with a brush and then to rinse after 3 minutes and then to reapply and repeat again.

For the average person soap and water is great but to state surgeons scrub and scrub is not comparing apples to apples. A surgeon scrubs and scrubs with a antimicrobial product to make sure they do a through job. The average person does not need to do such a good job.

The average person exposed to the average germ should use soap and water. If a sink is not easy to get to then an alcohol based sanitizer is great. Most people don't use it properly and don't use enough. While this article is great we need to educate people on how to wash hands and how to use hand sanitizers.

To wash hands in a public place one should use water and soap to get any visible dirt etc off the hands. Then after the person left the restroom and outside the door the person should use a hand sanitizer as the door or paper towel dispenser way have germs on it.

I may sound like a germophobe but Flu and the Cold and be transmitted by door knobs, sinks, and towel dispenser handles.

During the flu season researchers asked 125 people to go to a restroom 25 were asked to use soap and water, 25 were asked to not wash up , 25 were asked to use hand sanitizer before the left the restroom and the last 25 used 1 pump sanitizer after they left the restroom. The last group of 25 used two pumps each hand.

All of the groups were tracked and all the groups except the ones who used sanitizer 12 were exposed to significant amount of bacteria and the others were trace amounts. The group that used a small amount of sanitizer had 10 with a significant amount of bacteria. The group that used two pumps each hand had only trace amounts of bacteria.

Most product labels say apply a generous amount. Few actually tell you how much to use. The rule of thumb is make sure your hand remain wet for atleast 15 seconds it will evaporate in under 45 seconds so dont worry about using more because in this case more is better.

If the bottle has a pump use 2 pumps each hand then rub and make sure product gets under nails do not dry it of with a towel. If you must use a towel wait at least 25 seconds.

If the bottle has no pump pour at least about 1 teaspoon in each hand.

For more info about hand sanitizers search for info at or

For us in medicine, this has always been a double-edged sword. The immediate returns of antimicrobial use are great, but those mutating superbugs make us all aware of the downside...Happy New Year, all.

There are new hand sanitizers that kill 3 times the germs, work up to 30 minutes, and they are safer for kids than the ones that contain alcohol. This one is my favorite:


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