Chronic Bacterial Vaginal Infection That Is Not Bacterial Vaginosis
The condition you're describing is most likely Aerobic Vaginitis (AV), which should be treated with local kanamycin or, in severe cases with deep tissue involvement, oral amoxicillin-clavulanate or moxifloxacin targeting enteric gram-positive and gram-negative aerobes.
Understanding Aerobic Vaginitis
Aerobic vaginitis is fundamentally different from bacterial vaginosis despite both involving lactobacillary disruption 1. While BV is a non-inflammatory condition with multiple anaerobic bacteria, AV is characterized by:
- Sparse colonization with one or two enteric commensal bacteria (Streptococcus agalactiae, Staphylococcus aureus, or Escherichia coli)
- Marked inflammatory response or prominent epithelial atrophy
- Diagnosis by wet mount microscopy, not culture alone
Critical Diagnostic Pitfall
Do not treat vaginal culture results alone - this is a common mistake 1. Vaginal cultures only serve to confirm microscopy findings or exclude Candida. The diagnosis must be based on wet mount microscopy showing inflammatory cells and enteric bacteria, not the multiplex anaerobes seen in BV.
Treatment Algorithm
First-Line Approach
- Local non-absorbed broad-spectrum antibiotics covering enteric gram-positive and gram-negative aerobes
- Kanamycin is the preferred local antibiotic 1
- Avoid oral antibiotics in general practice since colonization is frequent but rarely causes inflammatory infection
Severe Cases Only
Use oral therapy for:
- Deep dermal vulvitis
- Severe colpitis with Group B Streptococcus or MRSA
- Amoxicillin-clavulanate or moxifloxacin orally 1
Component-Based Treatment
AV requires combined local treatment addressing three components 1:
- Infectious component: Antibiotic (as above)
- Inflammatory component: Topical steroids
- Atrophy component (if >10% parabasal cells): Local estrogens
Special Considerations
If Candida is present on microscopy or culture: Treat with antifungals first, then reassess if additional AV treatment is needed 1.
Rapid symptom relief: Vaginal rinsing with povidone-iodine provides quick relief but doesn't reduce bacterial loads long-term 1.
Postmenopausal or breast cancer patients: Consider probiotics with ultra-low dose local estriol if estrogens are contraindicated 1.
Why This Differs from Standard Vaginitis Treatment
The CDC guidelines 2 focus exclusively on BV, trichomoniasis, and candidiasis - they do not address aerobic vaginitis. This explains why patients with chronic symptoms fail standard metronidazole or clindamycin regimens designed for anaerobic bacteria in BV. AV requires aerobic coverage, not anaerobic coverage 1.
The 2015 research on AV 1 represents the most specific guidance for this under-recognized condition, which is frequently misdiagnosed as recurrent BV or intermediate flora on Nugent scoring.