In vivo antibacterial activity of chinfloxacin, a new fluoroquinolone antibiotic.
OBJECTIVE
To evaluate the in vivo antibacterial efficacy of chinfloxacin, a novel fluoroquinolone, in murine systemic and local infection models.


METHODS
The efficacy of chinfloxacin in systemic infection was evaluated in a mouse peritonitis model using isolates of methicillin-susceptible Staphylococcus aureus (MSSA, n = 3), methicillin-resistant Staphylococcus aureus (MRSA; n = 1), penicillin-intermediate Streptococcus pneumoniae (PISP; n = 1), penicillin-resistant S. pneumoniae (PRSP; n = 2), vancomycin-susceptible Enterococcus faecalis (VSE; n = 1), vancomycin-resistant E. faecalis (VRE; n = 2), Escherichia coli (n = 3) and Klebsiella pneumoniae (n = 2). The local infections included mouse pulmonary infections caused by penicillin-susceptible S. pneumoniae (PSSP; n = 1), PRSP (n = 1) and K. pneumoniae (n = 2).


RESULTS
In the mouse systemic infection model, chinfloxacin demonstrated potent activity against MSSA [50% effective dose (ED(50)) 2.28-4.15 mg/kg], MRSA (ED(50) 14.75 mg/kg), PISP (ED(50) 6.20 mg/kg), PRSP (ED(50) 3.51-5.03 mg/kg), VSE (ED(50) 25.02 mg/kg), VRE (ED(50) 5.18-15.39 mg/kg), E. coli (ED(50) 1.25-1.90 mg/kg) and K. pneumoniae (ED(50) 2.92-8.28 mg/kg). The therapeutic efficacy of chinfloxacin was generally similar to (P > 0.05) that of moxifloxacin, significantly higher (P < 0.01 or P < 0.05) than that of levofloxacin in Gram-positive isolate infections (MSSA, MRSA, PISP, PRSP, VSE and VRE), and less than that of levofloxacin against E. coli and K. pneumoniae infections (P < 0.01). In the mouse pulmonary infection model, chinfloxacin showed potent activity towards S. pneumoniae (higher than levofloxacin and ciprofloxacin) and K. pneumoniae (lower than levofloxacin and similar to or higher than ciprofloxacin) infections.


CONCLUSIONS
The results validated the potent efficacy of chinfloxacin in vivo. The high efficacy of chinfloxacin in murine systemic and local infections warrants investigation of its clinical use.
Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050,  China.
Guo-Qing
GQ
Li
Xiao-Gang
XG
Bai
Cong-Ran
CR
Li
Xin-Yi
XY
Yang
Xin-Xin
XX
Hu
Min
M
Yuan
Wei-Xin
WX
Zhang
Ren-Hui
RH
Lou
Hui-Yuan
HY
Guo
Jian-Dong
JD
Jiang
Xue-Fu
XF
You
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D004195:Disease Models, Animal; D005260:Female; D024841:Fluoroquinolones / Q000008:administration & dosage*; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy*; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010538:Peritonitis / Q000188:drug therapy*; D018410:Pneumonia, Bacterial / Q000188:drug therapy*; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones