Cell experiment:

Bacterial inocula are prepared by suspending colonies into Mueller-Hinton broth (CAMHB) (containing Ciprofloxacin hydrochloride) from 18 to 24 h (B. anthracis) or 42 to 48 h (Y. pestis) on sheep blood agar (SBA) plates that are incubated at 35℃. Suspended cultures are diluted with CAMHB to a bacterial cell density of 105 CFU/mL adjusted based on the optical density at 600 nm. To each well of the 96-well plate, 50 μL of dilutions is added for a final inoculum of ~5×104 CFU/well. Plates are incubated at 35℃. MICs are determined visually at 18 to 24 h (B. anthracis) or 42 to 48 h (Y. pestis) and also by absorbance at 600 nm[2].

Animal experiment:

Female BALB/cAnNCrl (BALB/c) mice, 8 to 10 weeks old and 20 g (±4 g) are used in this assay. A single dose of Ciprofloxacin hydrochloride (30 mg/kg) is administered to mice (n=30) via the intraperitoneal (i.p.) route. The mice (n=3/time point/group) are culled at 1, 10, 20, or 30 min and 1, 1.5, 2, 4, 8, 12 h following Ciprofloxacin hydrochloride (Bay-09867 (hydrochloride)) administration and 1, 15, or 30 min and 1, 2, 4, 6, 10, 18, or 24 h following DRCFI or CFI administration. Blood sampling points are chosen based upon the short half-life of Ciprofloxacin hydrochloride and longer half-life of CFI. Blood and lungs (whole organ) are collected post mortem for analysis. The lung doses following CFI or DRCFI administration are calculated using the concentration of Ciprofloxacin hydrochloride (Bay-09867 (hydrochloride)) in the lung samples at 1 min post-administration[3].

Ciprofloxacin (hydrochloride) is a fluoroquinolone antibiotic that has antimicrobial and immunomodulatory activities [1].

Ciprofloxacin functions by inhibiting DNA gyrase and topoisomerase IV, the enzymes responsible for negative supercoiling of chromosomes and DNA strand separation, thus blocking initiation of bacterial replication. Topoisomerase IV is the primary target of ciprofloxacin in S. aureus [2].

Ciprofloxacin (hydrochloride) is a fluoroquinolone antibiotic that acts as an antimicrobial and immunomodulatory agent. In B6D2F1/J mice received radiation combined injury (CI), Ciprofloxacin significantly reduced pro-inflammatory cytokine and chemokine concentrations (IL-6 and KC), and enhanced IL-3 production. CIP also inhibited CI-induced apoptosis and autophagy in ileal villi, systemic bacterial infection, and IgA production [1]. Ciprofloxacin (hydrochloride) had been approved by FDA for management of postexposure inhalational anthrax. In animals after exposure to aerosolized B. anthracis, ciprofloxacin significantly improved survival rate. Ciprofloxacin inhibited the growth of B. anthracis with MIC90 of 0.06 μg/mL. In the USAMRIID rhesus monkey model of inhalational anthrax, the maximum concentration (Cmax) of Ciprofloxacin was 1.74 μg/mL and the minimum concentration (Cmin) was 0.17 μg/mL [3].

References:
[1].  Fukumoto R, Cary LH, Gorbunov NV, et al. Ciprofloxacin modulates cytokine/chemokine profile in serum, improves bone marrow repopulation, and limits apoptosis and autophagy in ileum after whole body ionizing irradiation combined with skin-wound trauma. PLoS One. 2013;8(3):e58389.
[2].  Drlica K, Zhao X. DNA gyrase, topoisomerase IV, and the 4-quinolones. Microbiol Mol Biol Rev. 1997 Sep;61(3):377-92.
[3].  Meyerhoff A, Albrecht R, Meyer JM, et al. US Food and Drug Administration approval of ciprofloxacin hydrochloride for management of postexposure inhalational anthrax. Clin Infect Dis. 2004 Aug 1;39(3):303-8.