Aerobic Vaginitis

Aerobic vaginitis is vaginal inflammation caused by aerobic enteric or skin bacteria, mainly Escherichia coli, group B Streptococcus, Staphylococcus aureus and enterococci, with loss of lactobacilli.

It differs from bacterial vaginosis because the flora is aerobic, inflammation is marked and metronidazole does not cure it.

It is commoner in postmenopausal and oestrogen-deficient women and in pregnancy.

Left untreated it is linked to preterm labour and chorioamnionitis in pregnancy.

Yellow or green purulent discharge with burning, dyspareunia and vulval soreness.

• Vaginal erythema, sometimes with erosions or petechiae, a pH above 6, and no fishy odour.
• Symptoms persist after metronidazole or antifungals.
• Differential diagnosis: bacterial vaginosis, vulvovaginal candidiasis, trichomoniasis, desquamative inflammatory vaginitis, atrophic vaginitis, cervicitis, retained foreign body.
• Complications: chronic vaginitis, pelvic inflammatory disease, preterm birth, chorioamnionitis and neonatal infection.

Diagnosis rests on microscopy.

• Wet mount: reduced lactobacilli, increased leucocytes, toxic granular leucocytes, parabasal cells, and cocci or short bacilli.
• Vaginal pH above 6; negative amine test.
• High vaginal swab culture for E. coli, group B Streptococcus, S. aureus.
• Exclude trichomoniasis, gonorrhoea and chlamydia; HIV and syphilis tests.
• Random blood glucose if recurrent.

Treatment targets the aerobic bacteria with topical clindamycin and corrects oestrogen deficiency where present.

• Supportive: avoid douching and scented products; cotton underwear; wipe front to back; treat constipation and faecal soiling.
• Pharmacological: clindamycin 2 percent cream 5 g intravaginal nightly for 7 days. Alternative: amoxicillin-clavulanate 625 mg oral 8-hourly for 7 days. In postmenopausal women add oestriol 0.1 percent cream 0.5 g intravaginal nightly for 2 weeks then twice weekly for 8 to 12 weeks. Metronidazole alone is not effective.
• Procedures: none.
• Special groups: in pregnancy give amoxicillin 500 mg oral 8-hourly for 7 days and obtain a culture before and after treatment; avoid oestrogen cream. In women with penicillin allergy use clindamycin cream or clindamycin 300 mg oral 8-hourly for 7 days.
• Red flags: fever, lower abdominal pain, cervical motion tenderness (pelvic inflammatory disease), preterm labour or rupture of membranes in pregnancy.
• Follow-up: review at 2 to 4 weeks with repeat microscopy; recurrent cases need a search for atrophy, foreign body and glycosuria.