The First-in-Class Anti-Staphylococcal Antibiotic Afabicin Desphosphono is Not Associated With Clostridioides difficile Infection in an in vitro Human Gut Model.
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All Authors
Normington, C.
Clark, E.
Bentley, K.
Kaur, K.
Bromley, J.
Chogugudza, C.
Spittle, W.
Ewin, D.
Chaves, R.
Cameron, D.
LTHT Author
Clark, Emma
Wilcox, Mark
Wilcox, Mark
LTHT Department
Pathology
Microbiology
Microbiology
Non Medic
Healthcare Scientist
Publication Date
2025
Item Type
Conference Abstract
Language
Subject
Subject Headings
Abstract
Background. Antibiotic use is commonly associated with disruption of the healthy human gut microbiota (termed dysbiosis). Dysbiosis can diminish colonisation resistance and increase susceptibility to Clostridioides difficile infection (CDI). Use of the pathogen-Specific anti-Staphylococcal afabicin was not associated with dysbiosis in animals and healthy volunteers (Nowakowska et al, 2023). Here, we assessed whether this microbiota-Sparing property of afabicin would limit CDI in a clinically reflective in vitro human gut model. Methods. A well-established gut model was used as described previously (Baines et al, 2005). Four independent models were seeded with human fecal slurry (d0) and inoculated at d14 and d21 with C. difficile spores (107 CFU/mL). Two-week treatments were assessed beginning on d21 including (i) a CDI-positive control antibiotic levofloxacin (149.55 mg/L once daily), (ii) afabicin desphosphono high dose (35.7 mg/L twice daily [BID]), (iii) afabicin desphosphono mid dose (17.9 mg/L BID) and (iv) a vehicle control (1% DMSO BID). Endpoints for the model included facultative and obligate anaerobe counts, total viable and spore C. difficile counts and C. difficile toxin titre and were monitored daily until d63. Results. Each of the afabicin desphosphono treated models displayed colonisation resistance and no evidence of C. difficile germination or toxin production for the duration of the study. Further, no relevant changes in major facultative and obligate anaerobe groups were observed, indicating limited dysbiosis, similar to the vehicle control. In contrast, following a pre-treatment period where colonisation resistance was demonstrated (i.e. no germination following C. difficile inoculation), levofloxacin treatment resulted in dysbiosis characterized most notably by reductions (~5log10 CFU/mL) in facultative anaerobes including lactose fermenting Enterobacteriaceae. Dysbiosis caused by levofloxacin led to CDI including C. difficile germination and toxin production. Conclusion. Findings from this study provide further support for the microbiota-Sparing property of afabicin and suggest that limited off-targetmicrobiota effects associated with afabicin treatmentmay reduce incidence ofCDIwhen used clinically.
Journal
Open Forum Infectious Diseases