Acne Bacteria Resistance to Erythromycin

Factual Questions
1

I recently ran out of erythromycin for acne, and so did the pharmacy that I usually fill my prescription at. I have to wait until monday to get it, and because of this, I started reading the documentation on my old pledget container (I was bored).

One of the side effects mentioned was an overgrowth of erythromycin resistant acne bacteria. I have a few questions regarding this:

How common are these overgrowths with long term users of topical erythromycin? Are resistant bacteria floral or common? If not, how can I avoid coming into contact with strains of acne bacteria resistant to erythromycin. Will it take the introductionof a specific acne bacterium which happens to find the right pore, and will go on to cover all of my skin? Once this bacteria has become floral for me, how effective will my erythromycin be? Will it still slow down the division of acne bacteria or will everything just go to hell? If I stop using erythromycin, the resistant bacteria will gradually be taken over by normal acne bacteria, but will ANY use of erythromycinbring the resistant beceria roaring back? Will there be another antibiotic that I can switch to? What effect will the fact that I use a topical face wash with triclosan have on all of these questions?

Thanks a lot,
Elliot

2

I spent some more time with Google, and some studies for dermatologists said that around 60% of patients got some type of erythromycin resistant strain of acne bacteria. Unfortunately none of them really talked about the practical effects of this in terms of the number of pimples actually occuring compared to patients totally without erythromycin.

3

I would imagine the probability of resistance is dependent on several factors… length of antibiotic use, dose, topical vs. systemic use and geographical location.

Acne peaks between age 16-19 (earlier in guys) and in 90% of people resolves by age 24. Physicians look for the presence of comedones, cysts and scars and grade it from I-IV.

Washing twice a day is very important. If you are washing with triclosan, this will have a positive effect on the acne regardless of other treatments. Howevr, it probably would not effect antibiotic resistance. Soap, chlorhexidine, benzoyl peroxide and retinoic acids are also valuable.

Essentially, pilosebaceous units in the skin produce sebum. P.acnes bacteria promote lipolysis as well as produce chemotactic factors known to worsen acne. They may affect the complement pathway of the immune system as well.

Mild cases of acne are treated with topical ointments such as benzoyl peroxide, tretinoins, clindamycin, minocycline, erythromycin or coal tar. Moderate cases, with cysts or mild scarring, may be treated with long term systemic (oral) antibiotics. The most severe cases are treated with oral retinoids like Accutane – which reduce bacterial populations but which are teratogenic (induce birth defects) in women. Accutane does not seem to cause problems in fathers who use it.

Ironically, oral antibiotics have not been convincingly shown to decrease the population of Propriobacterium. Diet does not seem to effect acne, but genetics does with an autosomal dominant pattern in certain types.

To answer some of your questions… yes, you could switch to another antibiotic or other ointment easily in the case of antibiotic resistance. Resistance would not likely be caused by something you can avoid but a change within the actual bacteria. Once changed, the erythromycin would be much less effective regardless of how long you go without using erythromycin. Washing would help, but not affect the actual erythromycin resistance. Dermatologists aren’t concerned about this since many other options are available, and the problem often settles down with age. However, many would be more concerned about this problem with oral antibiotics and therefore they reserve these for more serious grades of acne.

Dr_Pap, MD.