Antibiotic Use Before Chlamydia and Gonorrhea Genital and Extragenital Screening in the Sexually Transmitted Infection Clinical Setting

Background antibiotic use (i.e. administration of antibiotics not directly related to Chlamydia trachomatis (Ct) or Neisseria gonorrhoea (GC)) infections has been associated with a lower prevalence of genital Ct infection in a clinical setting. Associations with specific antibiotic types or with GC are lacking. Here, we assess the prevalence of antibiotic use, the different classes and agents used and their association with a subsequent STI clinic Ct and GC test result. At our STI clinic, we systematically registered whether antibiotics were used in the past month (in 29% of the cases, the specific antibiotic agent was named). Patients were screened for urogenital Ct and Ng; a third of them were also screened for anorectal and oropharyngeal Ct and GC. The proportion of antibiotics used and their association with Ct and GC prevalence was assessed for heterosexual men, men who have sex with men (MSM) and women. During 14775 clinic consultations, antibiotic use was reported by 12.2% (95% CI: 95% CI: 11.7%-12.7%), i.e. 14.8% of women, 8.6% of heterosexual men and 11.6% of MSM. Tthe most reported antibiotics were penicillins, tetracyclines and macrolides, respectively. The prevalence was 11.0% (95%CI: 10.3%-11.3%) for Ct and 1.9% (95% CI: 1.7%-2.1%) for GC. Only tetracycline use was associated with a lower Ct prevalence (3%). Overall antibiotic use was associated with lower anorectal Ct prevalence in MSM only (odds ratio: 0.4, 95% CI: 0.2-0.8). STI clinic visitors commonly report recent antibiotic use. Even in a country with low antibiotic consumption, tetracycline use impacted Ct prevalence, while there was a notable absence of association with azithromycin.