The efficacy of short term amoxicillin therapy and the effect of furosemide on conventional antibiotic therapy in experimentally induced bacterial lower urinary tract infection in cats

Abstract

The efficacy of short term (3 day) oral amoxicillin therapy was compared to conventional (14 day) oral therapy in an experimental model of bacterial lower urinary tract infection (UTI) in the cat. Chemical cystitis was induced using an infusion solution of salicylic acid, 70% ethanol, and normal saline via transabdominal cystocentesis. Cats were challenged with a Staphylococcus intermedius inoculum twenty-four hours later introduced via urethral catheterization. Serial quantitative aerobic bacterial urine cultures obtained via cystocentesis were used to evaluate groups of cats.

Eighteen adult cats (9 males and 9 females) were divided into 3 groups of 6 cats (3 males and 3 females): Group I = conventional amoxicillin therapy (14 day), Group II = control group (no treatment), and Group III = short term therapy (3 day). Results indicated the conventional therapy successfully eradicated infection, however, the short term therapy did not eradicate infection when compared to controls. During the study period the diuretic furosemide was used in some cats to facilitate cystocentesis procedures. Those cats were observed to exhibit less stranguria, which is a common sign of lower UTI.

The second study evolved from observations made in the first study and evaluated the effect of furosemide on conventional antibiotic therapy in an experimental model of bacterial lower UTI in the cat. A similar experimental design was utilized with Group I = control group (no treatment), Group II = oral furosemide (14 day), and Group III = oral furosemide and oral amoxicillin (14 day). Statistical analysis failed to demonstrate the efficacy of the furosemide and amoxicillin combination, but showed furosemide alone was not an appropriate therapy when compared to controls. It was again observed that those cats receiving furosemide showed fewer secondary signs of lower UTI such as stranguria which suggests a possible role for furosemide as adjunct therapy in the treatment of lower UTI in the cat.