Background:

Ciprofloxacin (Bay-09867) is a fluoroquinolone antibiotic, exhibiting potent antibacterial activity.
Ciprofloxacin (Bay-09867) is a fluoroquinolone antibiotic, exhibiting potent antibacterial activity[1]. Ciprofloxacin (CIP) shows potent activity against Y. pestis with MIC90 of 0.03 μg/mL[2].
Ciprofloxacin (Bay-09867) (1 mg/L) induces glutathione-S-transferase (GST) activity, in contrast with inhibited GST and Catalase (CAT) of larvae exposed to enrofloxacin. Ciprofloxacin (Bay-09867) (≥10 μg/L) and enrofloxacin are ecotoxic for development, growth, detoxifying, and oxidative stress enzymes in anuran amphibian larvae[1]. In a murine model of pneumonic plague, Ciprofloxacin (Bay-09867) (30 mg/kg, i.p.) results in a drug exposure which is similar to the drug exposure observed in human following a 500 mg dose of oral Ciprofloxacin (Bay-09867). Intraperitoneal Ciprofloxacin (Bay-09867) reduces the lung bacterial load compare to controls treated with intraperitoneal PBS[3].
Reference:
[1]. Peltzer PM, et al. Ecotoxicity of veterinary enrofloxacin and ciprofloxacin antibiotics on anuran amphibian larvae. Environ Toxicol Pharmacol. 2017 Feb 4. pii: S1382-6689(17)30029-7
[2]. Steenbergen J, et al. In Vitro and In Vivo Activity of Omadacycline Against Two Biothreat Pathogens: Bacillus anthracis and Yersinia pestis. Antimicrob Agents Chemother. 2017 Feb 21.
[3]. Hamblin KA, et al. Inhaled Liposomal Ciprofloxacin Protects against a Lethal Infection in a Murine Model of Pneumonic Plague. Front Microbiol. 2017 Feb 6;8:91.