title: Bacterial resistance to antibiotics in acne vulgaris: an in vitro study.
abstract: BACKGROUND
  Acne vulgaris is one of the most common skin disorders in youth especially during the puberty.
  
  
  OBJECTIVE
  This in vitro study was performed to determine the antibiotic resistance and sensitivity in acne vulgaris.
  
  
  METHODS
  Samples were collected from normal skin and nodulocystic and pustular skin lesions of one hundred youngsters (64 girls, 36 boys) among college students in the age range of 18-24 years old. The specimens were cultured individually on blood agar and Muller-Hinton media. The cultures were then incubated under both aerobic and anaerobic conditions for 2 to 7 days. Bacteria were identified and their resistance to common antibiotics was evaluated according to the standard procedures.
  
  
  RESULTS
  In aerobic culture of pustular and nodulocystic skin lesions, Staphylococcus aureus was present in 41% of subjects, Staphylococcus epidermidis in 53% and Micrococcus spp in 45% of subjects. In anaerobic bacterial culture of pustular and nodulocystic skin lesions, Staphylococcus aureus was present in 39%, Propionibacterium acne in 33% and Staphylococcus epidermidis in 21% of subjects. The results of present study revealed that clindamycin and erythromycin were the least effective antibiotics for Propionibacterium acne while tetracycline was the least effective for Staphylococcus aureus in vitro. A synergic effect of benzoyl peroxide, erythromycin or clindamycin was noticed. Rifampin was the most effective antibiotic in vitro.
  
  
  CONCLUSIONS
  Our results showed that rifampin was the most sensitive antibiotic in vitro for acne vulgaris. To achieve a better treatment, a combination of rifampin with other antibiotics may be more efficient. We suggest in vivo studies for better evaluation and treatment of acne patients with rifampin.
authors.affiliation: Department of Biology, School of Sciences, Shiraz University, Shiraz, Iran. hassanzadeh@susc.ac.ir
authors.forename: Parvin
authors.initials: P
authors.lastname: Hassanzadeh
authors.forename: M
authors.initials: M
authors.lastname: Bahmani
authors.forename: Davood
authors.initials: D
authors.lastname: Mehrabani