Vaginal pH and microbiota during fluconazole maintenance treatment for recurrent vulvovaginal candidosis (RVVC)

It is commonly stated that Candida in the vagina prefers a low pH to develop infection. However, mixed infections of Candida with bacterial vaginosis (BV) and aerobic vaginitis (AV) are rather common and may challenge the rule that Candida should only be looked for in low vaginal pH settings. In this study we tested whether the vaginal pH in acute vaginal candidosis is lower than in women successfully treated to prevent Candida recurrences.

Vaginal pH and microscopy findings of vaginal microbiota were recorded during 12 visits over 1.5 years in 117 patients medically monitored during a degressive fluconazole maintenance regimen for proven recurrent vulvovaginal candidosis (ReCiDiF trial). The fluctuation of the mean pH of and microscopic findings of the vaginal smears were studied before, during and after the treatment.

The mean vaginal pH of women with acute infection before or after ending maintenance treatment was (4.7±0.8 and 4.8 ±1.0, respectively, p>0.05). During maintenance treatment with fluconazole, the pH dropped significantly to 4.5±0.8 (p=0.01). Depression of Lactobacilli spp. (increased lactobacillary grades) was more frequent during the acute, pre-treatment period (30.0%) than during the treatment period (23.1%, p=0.03). Aerobic vaginitis type flora was also more prevalent pre-treatment than during treatment (30.0% vs 22.2%, OR=0.7 (95%CI 0.5-0.9), p=0.01).

In women with RVVC, acute vaginal Candida infection is associated with an increased pH, and disturbed vaginal bacterial microbiota. During fluconazole maintenance treatment, the pH drops to normal levels and the lactobacillary grade improves.

Acute Candida vulvovaginitis can be associated with a disturbance of the vaginal microbiota. In patients with recurrent vulvovaginal candidosis, decrease of pH, and increase of Lactobacilli spp. were observed during fluconazole maintenance treatment. This pH drop was seen in all response groups. This contradicts the common belief that active vaginal Candida infection is related to low pH.