Successful endometriosis treatment now possible with antibiotics, finds RCT

Chronic endometritis (CE), defined as the abnormal invasion of plasma cells within the endometrial stroma, has been one of the most investigated conditions.

Recent studies based on molecular biology-based methods and endometrial culture showed that chronic endometritis was often associated with an abnormal endometrial microbiome, with the local proliferation of common gram-positive (i.e., streptococci, staphylococci) or gram-negative (i.e., Escherichia coli, Klebsiella pneumoniae, Neisseria gonorrhoeae) or less common intracellular (Mycoplasmi, Ureaplasmi, Chlamydiae) or anaerobic (bifidobacteria, Prevotella) bacteria.

The randomized controlled trial by Song et al. brought to light the potential effectiveness of empiric double-regimen oral antibiotic therapy (i.e., levofloxacin 500 mg and tinidazole 1,000 mg daily for 14 days) for Chronic endometritis cure. "This was the first study studying the effects of antibiotics for endometritis treatment with even blinding of pathologists" as illustrated by author.

Interestingly, the investigators found "CE test negative rate was 89.3% after a single course of antibiotics in the treatment arm compared with 12.7% in the control group.In particular, levofloxacin would be active against most gram-positive and gram-negative bacteria including streptococci, staphylococci, and Enterobacteriaceae. Tinidazole would provide coverage for most intracellular and anaerobic bacteria includingUreaplasma, Mycoplasma, and bifidobacteria. On this basis, the combination of levofloxacin and tinidazole may offer appropriate antibiotic coverage against most pathogens involved in CE."

However, the increased use of antibiotics, especially quinolones cites a concern for possible increase in antibiotic resistance in individuals.

In order to avoid the situation, another recent retrospective case-control study was conducted that evaluated the effectiveness of a personalized, antibiogram-guided antibiotic treatment. "The approach led to a cumulative cure rate of 81.3% after 3 antibiotic cycles, which was inferior to the success rate of empiric therapy in the study by Song et al. (89.3% after a single antibiotic cycle)".

Cons of the study :

1. The treatment arm did not experience a significant improvement in the conception rate at 12 months follow-up
2. Additionally, among subjects who attempted pregnancy, the investigators found no difference between groups in terms of ongoing pregnancy rate and miscarriage rate
3. The diagnosis of chronic endometritis relied on the immunohistochemical detection of plasma cells in endometrial biopsy specimens. Given the blind nature of the endometrial sampling in the study by Song et al. (i.e., endometrial curettage), a certain bias in the estimates of CE cure was implicit

Song et al. provided a new evidence from a randomized, controlled trial about the effectiveness of empiric, broad-spectrum antibiotic therapy for chronic endometritis as published in Fertility and sterility journal

Nonetheless, some issues within the study limit the conclusions that can be drawn about the impact of chronic endometritis and its treatment on female fertility. While appropriate antibiotic regimens may definitely cure CE, the understanding of the relationship between CE therapy and female fertility appears a more challenging matter.