Promising Effect of Levofloxacin and Cefoxitin for Quinolone Resistant Pathogens

Background: The rise in antibacterial resistance, coupled with limited new antibiotic development, necessitates optimized treatment strategies, particularly through antibiotic combinations. Combination therapy offers advantages such as synergy, rejuvenation of older drugs, reduced resistance development, broadened spectrum, and toxicity avoidance. Objective: To identify synergistic combination treatments against clinical multidrug-resistant (MDR) isolates, specifically: Focusing on Levofloxacin in combination with other antibiotics. Methodology: The study employed an observational experimental design, testing the combinations of Levofloxacin with Amikacin, Cefoperazone, and Cefoxitin, and the Fractional Inhibitory Concentration Index (FICI) was used to interpret results, with synergy defined as FICI ≤ 0.5. Results: Regarding combinations, Levofloxacin and Amikacin, demonstrated a significant synergistic effect in 75.0% of Gram-positive isolates, reaching 100.0% for Staph. aureus. Levofloxacin and Cefoperazone, showed 93.8% no interaction for Gram-positive isolates. Levofloxacin and Cefoxitin, achieved a synergistic effect in 56.3% of Gram-positive and 70.6% of Gram-negative isolates, with S. aureus and with K. pneumoniae showed 80.0% synergy. This combination was identified as the most synergistic overall, with 66.0% synergy. Conclusion: The study successfully identified Levofloxacin and Cefoxitin as the most effective synergistic combination against both Gram-positive and Gram-negative pathogens, highlighting its potential for optimizing treatment against quinolone-resistant bacteria. This underscores the importance of combination therapy in combating the growing threat of antimicrobial resistance.