antimicrobial activity of nitroxoline against uropathogens isolated from China.

BACKGROUND AND OBJECTIVES

The antimicrobial nitroxoline is used in treating uncomplicated urinary tract infections (UTIs) in some European countries. antimicrobial data on uropathogens from China are lacking. To investigate the activity of nitroxoline against uropathogens isolated from Chinese patients.

METHODS

MICs of nitroxoline were determined using broth microdilution of 229 bacterial isolates of 10 species including derived from urinary sample. The EUCAST susceptibility breakpoint for (16 mg/L) was applied for all isolates. The MBC for ( = 34) was determined, with the MBC defined as the nitroxoline concentration at which a 99.9% reduction in the initial inoculum was observed. Time-kill curves of the two isolates of were tested over a 24 h period.

RESULTS

Except for , most isolates were susceptible to nitroxoline. The MIC50/90 values of nitroxoline for , and were 4/8, 8/32 and 8/16 mg/L, respectively. Among the Gram-negative isolates, nitroxoline demonstrated a better inhibitory effect against with an MIC50/90 value of 2/2 mg/L. The MBC of was equal to the MIC or one dilution higher. The time-kill curves of displayed concentration-dependent killing.

CONCLUSIONS

Nitroxoline showed excellent activity against uropathogens isolated from China and may be a good option for uncomplicated UTIs caused by , which are more challenging and have few clinical options. Further efficacy studies are needed.