April 14, 2009

Mutant Acne-Causing Bacteria Grow Increasingly Resistant

As if teenagers didn't already have enough to worry about, dermatologists across the country are warning that the bacteria responsible for causing acne are growing increasingly resistant to the commonly prescribed antibiotics like tetracycline and erythromycin.

While most medical professionals are all too familiar with the incredible mutating abilities of super-bacteria like MRSA, most people are unaware that the lowly bacterium responsible for so many insecure teenage years (appropriately named P. acnes), is also able to avoid antibiotic drugs by changing its genetic make-up.

"There's been so much attention to MRSA and other kinds of resistant bacteria which truly can kill you, whereas acne doesn't kill you," says Alan Fleischer, the chair of dermatology at Wake Forest University School of Medicine.  "Yet we doctors see patients who have resistant acne and we do need to be cognizant of changes.  The bacteria are changing, are adapting and becoming resistant."

Antibiotics, which attack and kill bacteria, are among the most commonly used treatments for severe acne.  However, as dermatologists are beginning to recognize an increasing immunity against the antibiotics amongst patients, they are being forced to resort to other tools in the fight against acne.  And for those patients who do still receive antibiotics, they are being used for shorter amounts of time "“ months instead of years "“ and in combinations with other types of medications that help to lower the bacteria's resistance.

The fear amongst dermatologists is that continued, heavy use of antibiotics may lead to a drug resistance in the population at large as super-resistant bacteria become increasingly immune treatment.


Though acne can be emotionally traumatizing, the real health threat is the possibility that drug resistance could spread to other species of bacteria.

According to Dr. Peter Lio, a dermatologist at Northwestern University: "The dangerous thing about putting zillions of folks on antibiotics is that this pressures bacteria to develop to develop resistance methods"¦So while the acne bacteria almost never causes life-threatening infection, the ways that it can be resistant to our antibiotics can be passed over to bacteria that can cause life-threatening infection, which means that our only weapons against the bad guys suddenly do not work anymore."

Unlike animals, bacteria are able to exchange genetic information between different species through several different biological processes, such as transformation and transduction.  It is an evolutionary survival mechanism that has allowed bacteria to be one of the oldest and, by some standards, most successful forms of life on Earth.

"If it [bacterial resistance] became bad enough," said Dr. Lio, "it would be like the days before antibiotics, when infection was a common cause of death."

Between 75 and 90 percent of teenagers suffer from acne at some point during adolescence, while a surprising 50 of adults also have it to some degree.

"Acne is a really tough disease," added Lio.  "We can make a big difference with many patients, but it's a humbling disease; it brings people down.  People can be incredibly depressed coming in, so our job is to do whatever it takes to make them better."

Though there have been relatively few studies on drug-resistant acne up till now, a 2001 study from French researchers found that an astonishing 50 of the isolated P. acnes bacteria showed resistance to erythromycin, one of the most commonly used antibiotics.  Researchers suspect that some 10 to 30 percent of acne patients carry at least some of the resistant bacteria strains.


16-year-old Chris Fields, a high-school sophomore in Concrete, Washington, is all too familiar with the psychological and emotional stress caused by severe acne.  About half a year ago, his dermatologist had him start a tetracycline regimen of 500 mg a day.  Within a month his skin had dramatically cleared and he was feeling confident enough to look people in the face again.

"I had more self-confidence and stuff," he said.  "When I'd go out in public, I'd actually look people in the eye and not be so worried about how my face looks.  Right now, that's starting to slip away again."

As is often the case with antibiotic-resistant acne, Field's skin was clear for about two months before his acne seemed to come back with a vengeance.  Next week he'll go back to his dermatologist to see if they can figure out what went wrong and to determine what the next step in his treatment will be.

Keri, a dermatologist in Miami, says that one of the most common problems with acne treatment is that doctors in private practices don't typically test their patients for resistance.  "If they thought [patients] were resistant, they might switch antibiotics or add topical treatment to the mix."  Instead, they usually just increase the dosage of the antibiotic or switch to another one, thus increasing the probability that the bacteria will develop further resistance.


Whether or not a patient is resistant, there are numerous ways to attack the problem of acne, since the bacteria only constitute one step in pimple-forming process.

First, the amount of oil in a pore increases.  Then, the skin cells inside the pore become sticky from the excess oil, which eventually causes the pore to clog.  Next, the bacteria come in and begin to feed on the oil and reproduce.  Finally, the body's immune response recognizes the growing colony of bacteria and begins to fight against it, causing the red inflammation typically associated with a pimple.

"The fact is, because acne is much more complicated than a simple infection, there really are a wide variety of other approaches that are very useful," says Dr. Fleischer.

Fewer and fewer doctors are relying on antibiotics alone to treat acne these days.  In a 2005 study co-authored by Fleischer, he and his colleagues found that a major shift had taken place in the field of dermatology and that that more doctors than ever were resorting to non-antibiotic treatments.  Fleischer noted that when he began his practice 20 years ago, erythromycin was by far the most commonly used form of acne treatment.  "Now maybe I have one patient on it," he says.

"Acne is not a life-threatening situation; it is a quality of life situation.  Using drugs that don't display drug resistance will allow us to make patients look and feel better." 

For millions of self-conscious teenagers across the world, they couldn't ask for more.


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