Gardnerella vaginalis and Trichomonas vaginalis infections and the risk of persistence or progression of low-grade cervical intraepithelial neoplasia

Gardnerella vaginalis (GV) and Trichomonas vaginalis (TV) infections have been proposed as risk factors for persistence or progression of low-grade precancerous cervical lesions (CIN1/L-SIL). However, their role is still undefined. We aimed to assess if GV and TV infections affect the risk of persistence/progression of CIN1/L-SIL. A retrospective cohort study was performed to assess the risk of CIN1/L-SIL persistence or progression, persistence alone and progression alone in patients with GV and/or TV infections (GV + and/or TV+), only GV (GV+), only TV (TV+), or GV and TV coinfections compared to patients without these infections. Relative risk (RR) with 95 % confidence intervals (CI) was adopted (significant p-value>0.05). Two hundred and seventy patients were included. RR for CIN1/L-SIL persistence or progression was 1.63 in GV + and/or TV+ (p = 0.02), 1.99 in GV+ (p = 0.0008), 0.25 in TV+ (p = 0.32), 1.78 in coinfection (p = 0.26). RR for persistence was 1.55 in GV + and/or TV+ (p = 0.1), 2.179 in GV+ (p = 0.0013), 0.32 in TV+ (p = 0.41), 0.45 in coinfection (p = 0.55). RR for progression was 1.92 in GV + and/or TV+ (p = 0.22), 1.34 in GV+ (p = 0.68), 1.16 in TV+ (p = 0.91), 8.39 in coinfection (p = 0.0002). In conclusion, GV infection may be a risk factor for CIN1/L-SIL persistence. TV infection alone does not significantly affect the risk of persistence or progression of such lesions, while it may greatly increase the risk of progression when associated with GV infection.