The In Vitro Antibacterial Effects of Genipin Against Pathogens Commonly Associated With Infected Ulcerative Keratitis: A Canine Preliminary Study.

PURPOSE: To evaluate genipin as a novel antimicrobial therapeutic agent with established crosslinking abilities by investigating its antibacterial activity against canine ocular pathogens and exploring its pharmacodynamic profile.

METHODS

Nineteen bacterial strains were selected from frozen stock, including ten Staphylococcus pseudintermedius (five of which were methicillin-resistant [MRSP]), five Pseudomonas aeruginosa, and four Streptococcus canis. All strains were isolated from dogs with corneal stromal ulcerations. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were examined; subsequently, time-kill assays were performed. Viability counts were performed at 0, 10, 30, 60, and 120 minutes.

RESULTS

Blue discoloration of the contents in the wells impeded the determination of the MIC values for all pathogens. MBC values ranged from 0.1% for MRSP, 0.075%-0.125% for S. pseudintermedius and P. aeruginosa, and 0.25%-0.5% for S. canis. Time-kill analysis demonstrated a mean bacteriostatic effect of genipin against staphylococci at 1 × MBC after 120 minutes, and a mean bactericidal effect after 120 minutes at 2.5 × MBC and after 60 minutes at 5 × MBC. No antibacterial effect was measured for P. aeruginosa within the tested timeframe and genipin concentrations.

CONCLUSIONS

Genipin exhibited promising antibacterial activity against all tested isolates, including MRSP. We suggest that genipin acts as a concentration-dependent antimicrobial agent, demonstrating bactericidal activity at higher concentrations against staphylococci. P. aeruginosa appeared less susceptible to the short-term effects of genipin. Further investigation is warranted to elucidate genipin's full antimicrobial potential and clinical performance.