Antimicrobial treatment for human intestinal spirochaetosis: a systematic review

The antimicrobial treatment options for patients with intestinal spirochaetosis (caused byBrachyspira pilosicoliandBrachyspira aalborgi) are not well defined. We aimed to systematically review the literature to explore antimicrobial treatment options to inform future clinical guidelines.We systematically searched three bibliographical databases (MEDLINE, EMBASE, SCOPUS and Web of Science) for manuscripts written in English up to January 2024. The primary author conducted an initial abstract screen and two authors conducted independent full-text reviews. We included manuscripts which included primary data for patients with intestinal spirochaetosis who had received antimicrobial treatment and had an outcome measured. Quality and risk of bias was assessed independently by two authors using the Joanna Briggs Institute critical appraisal tools. We used the nine-point synthesis method to synthesise narrative data.There were 58 manuscripts included in this review published between 1977 and 2023 (42 case reports, 12 case series, 3 cross-sectional studies, and 1 prospective cohort). In total, there were 270 individuals with intestinal spirochaetosis: 225 patients received oral metronidazole monotherapy, 1 intravenous metronidazole, 2 rectal metronidazole, 5 metronidazole as part of a dual/triple regimen, 17 doxycycline monotherapy, 5 doxycycline (or tetracycline) dual therapy with either a beta-lactam, or neomycin, 4 benzathine penicillin, 1 procaine penicillin/steroids and 3 other antimicrobials including clarithromycin and vancomycin. 230 (85%) of patients in this review had an adequate clinical and or histological response to treatment with a median follow-up period of 30 days (IQR 14–90). The combined treatment response to all metronidazole-based treatment was 195/233 (84%).Metronidazole, doxycycline and parenteral penicillin are the most frequently used antimicrobials for the treatment of human intestinal spirochaetosis and treatment response is generally good. More work is needed to understand the pathophysiology and treatment outcomes in patients with symptomatic intestinal spirochaetosis including the development of non-invasive diagnostic tools.