BAY-Y 3118, a new chlorofluoroquinolone, has antimicrobial activity.

BAY-Y 3118 exhibits potent activity against Haemophilus influenzae, Moraxella catarrhalis, Acinetobacter baumannii, Xanthomonas maltophilia, gram-positive cocci, and anaerobes, with MIC50s and MIC90s of ≤0.015 and ≤0.015, ≤0.015 and ≤0.015, 0.03 and 2, 0.25 and 0.5, 0.06 and 1, and 0.12 and 0.25 μg/mL, respectively [1]. It achieves a cellular concentration-to-extracellular concentration ratio above 6.3 at extracellular concentrations of 2 to 100 mg/L, demonstrating rapid, reversible, nonsaturable uptake. Its intracellular penetration is significantly influenced by environmental temperature and cell viability. BAY-Y 3118 attains high intracellular levels within human polymorphonuclear leukocytes (PMNs) and remains active within these cells [2]. In vitro, BAY-Y 3118 is rapidly bactericidal, exhibiting a postantibiotic effect for 3 hours after antibiotic removal, and effectively eliminates L. monocytogenes from infected L929 cells [3].

Immunocompetent mice treated with 4 mg every 12 hours are rapidly cured, with interleukin 6 and gamma interferon levels in mouse sera declining swiftly. Additionally, treatment in immunocompetent mice with 2 mg of BAY-Y 3118 every 12 hours results in a greater initial reduction in listerial counts in organs compared to 2 mg of ampicillin every 12 hours [3].