Comparison Between Moxifloxacin and Chloramphenicol for the Treatment of Bacterial Eye Infections

Valentina Gentili; Giovanni Strazzabosco; Rossella Spena; Sabrina Rizzo; Silvia Beltrami; Giovanna Schiuma; Andrea Alogna; Roberta Rizzo

doi:10.1016/j.curtheres.2024.100740

Comparison Between Moxifloxacin and Chloramphenicol for the Treatment of Bacterial Eye Infections

Curr Ther Res Clin Exp. 2024 Feb 28:100:100740. doi: 10.1016/j.curtheres.2024.100740. eCollection 2024.

Authors

Valentina Gentili¹, Giovanni Strazzabosco¹, Rossella Spena², Sabrina Rizzo¹, Silvia Beltrami¹, Giovanna Schiuma¹, Andrea Alogna¹, Roberta Rizzo¹

Affiliations

¹ Department of Chemical, Pharmaceutical, and Agricultural Science, University of Ferrara, Ferrara, Italy.
² Department of Translational Medicine, University of Ferrara, Ferrara, Italy.

Abstract

Background: Moxifloxacin is a bactericidal methoxyquinolone used for the treatment of conjunctivitis and prophylactic therapy in cataract and refractive surgeries. Chloramphenicol is a bacteriostatic organochlorine introduced into clinical practice in 1948 and used mainly in topical preparations because of its known toxicity.

Objectives: The study aimed to evaluate the in vitro antibacterial effect and the ocular cytotoxicity of these broad-spectrum antibiotics.

Methods: Antimicrobic activity was tested on 4 bacteria strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis), and determined through calculation of MIC and half inhibitory concentration for each microorganism. Antibacterial activity was determined by microdilution method after 24 hours' incubation with 2-fold serial dilutions (2.5 mg/mL to 4.883 µg/mL) of moxifloxacin and chloramphenicol. Disk diffusion test were performed according to European Committee on Antimicrobial Susceptibility Testing methodology. Biofilm formation inhibition and biofilm eradication concentration assay were conducted for P aeruginosa and S epidermidis using the microdilution method. Cytotoxicity of antibiotics was evaluated by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) colorimetric assay on human corneal cell.

Results: Cytotoxicity of antibiotics was evaluated on human epithelial corneal cells after 4 hours treatment by viability assay. Results showed that corneal cell viability was significantly higher after moxifloxacin treatment compared with chloramphenicol (P < 0.01). Moxifloxacin is characterized by a significantly lower MIC and half inhibitory concentration values and a larger inhibition zone for all the strain tested, with high performance in controlling gram-negative growth, compared with chloramphenicol. Moreover, moxifloxacin showed higher activity compared with chloramphenicol in the inhibition of biofilm formation and in the disruption of biofilm, especially against S epidermidis biofilm.

Conclusions: The lower corneal cell toxicity and the broader spectrum of antibacterial activity observed with moxifloxacin suggests its use in ophthalmic solution for the treatment of bacterial eye infections.

Keywords: Antibacterial activity; Antibiofilm; Cytotoxicity; Prophylaxis.