Effect of antibiotics on the oropharyngeal flora in patients with acne

To estimate the prevalence and resistance patterns of Streptococcus pyogenes and Staphylococcus aureus in the oropharynx of individuals with acne who were using or not using antibiotic therapy.

A cross-sectional study.

The Dermatology Department of the Hospital of the University of Pennsylvania, Philadelphia.

Patients with acne.

Presence or absence of S pyogenes and S aureus in the oropharynx as determined by culture and their resistance patterns to tetracycline antibiotics as determined by agar disk diffusion.

Of 105 patients who participated, 42 were using oral or topical antibiotics and 63 patients were not using antibiotics. Six (10%) of those 63 not using any antibiotics had positive S pyogenes cultures compared with 13 (33%) of those successfully evaluated using antibiotics (n = 39) (prevalence risk ratio, 3.5; 95% confidence interval, 1.4-8.6; P=.003). A total of 85% of S pyogenes cultures (11/13) from those using antibiotics were resistant to at least 1 tetracycline antibiotic compared with 20% (1/5) from those not using antibiotics (P=.01). Of those not using antibiotics, 29% (18/62) had positive S aureus cultures compared with 22% (9/41) of those using antibiotics (prevalence risk ratio, 0.76; 95% confidence interval, 0.38-1.5; P=.42). No significant differences in resistance patterns of S aureus were found.

Streptococcus pyogenes colonization and resistance in the oropharynx are associated with antibiotic therapy in patients with acne. The clinical and long-term effects of this finding need to be studied further.