In vitro activity of norfloxacin against uropathogens and drug efficacy in simulated bladder model under diabetic conditions

The in vitro activity of norfloxacin was determined to maximize the correlation between susceptibility testing of the drug and the results of clinical therapy of urinary tract infection in diabetics. This study was carried out to observe the effect of changing concentration of norfloxacin on the growth of uropathogens under diabetic conditions.

The standard broth microdilution method was carried out to determine the minimum inhibitory concentration (MIC) using Mueller Hinton broth by varying pH of the medium (5.0, 5.5, 6.0, 6.5 and 7.0) and glucose concentration (100, 250, 500, 1000 and 2000 mg/dL). A specially designed mechanical bladder model system simulating hydrokinetic conditions that exist in the urinary tract of diabetics was employed.

The loss of activity of norfloxacin was more pronounced (> four folds) at pH 5.0 and 2000 mg/dL sugar concentration. These findings were consistent with the experiment 'in vitro simulated bladder model' by exposing bacterial growth to varied norfloxacin and sugar concentration.

Although norfloxacin is a drug of choice for non-diabetic and diabetic individuals with mild to moderate glucosuria, in severe diabetic individuals norfloxacin may not be an effective drug.