Seventy one male bodybuilders using AAS were studied. In addition 23 male bodybuilders AAS non-users and 46 non-athlete students, with similar gender and age range, were selected as the control group. The average and median ages of the bodybuilders were 24.7 and 24 years, respectively. All the participants completed a questionnaire including bathing habits, using AAS and other supplements, administration of antimicrobial drugs for at least four weeks, and general medical conditions. The study was approved by the ethics committee of Shiraz University of Medical Sciences. All the participants willingly provided written informed consent approved by the ethics committee of Shiraz University of Medical Sciences. The skin of the examinees was checked for the presence of the lesions. Specimens were obtained from the skin surface by swabbing 1 cm2 of the back and chest areas by two wet swabs. Those received systemic or topical antibiotic drugs during the month before sampling were excluded from the study.
The swab was directly spread on Tryptone Soy Agar (Merck, Germany) supplemented with 5% v/v defibrinated sheep blood under an anaerobic condition at 37°C to isolate
P. acnes and under aerobic condition for
S. aureus species. The isolated strains of
S. aureus were identified by standard methods including colony morphology, gram stain, catalase test, mannitol fermentation and coagulase test on aerobic overnight cultured samples. To isolate
P. acnes, following seven days of anaerobic incubation, the plates were examined to detect bacterial colonies that were not present in the aerobic conditions. Suspected anaerobic colonies were then subcultured in the aerotolerance plates.
P. acnes were identified by lack of growth in aero tolerance plate, colony morphology, Gram stain, and indole test (S+) (
14). The number of isolated bacteria from each swab was counted and recorded for each bacterium per anaerobic and aerobic plates. The quantity of both isolated
P. acnes and
S. aureus from each sample site was clustered into four groups (0, 1-9, 10-49, > 50) based on the corresponding colony forming unit/cm
2 (CFU/cm
2). The χ2 test was used to examine the bacterial colonization at the examined sites between the AAS users and the others. Values of P < 0.05 were considered statistically significant.