The use of fluoroquinolones in bacterial urinary tract infections in cats

Older cats (> 10 years) with FLUID (Feline Lower Urinary Tract Disease) symptoms are often affected by urinary tract infections. In most of these cats organ diseases (e. g. chronic renal failure, diabetes mellitus) or iatrogenic factors (immunosuppressive drugs, indwelling catheter) are found that clearly predispose cats to this kind of infection. From a diagnostic point of view, urinalysis and urine culture are the most important tools in detecting bacteriuria. The microbiological spectrum is thereby comparable to that found in dogs, revealing Escherichia (E.) coli but also Staphylococcus spp. and Enterococcus spill Streptococcus spp. Antibiotic therapy should be based on the results of susceptibility testing. If this kind of information is not available, drug selection has to be decided on an empirical basis unless it is a complicated urinary tract infection. Preferred antibiotics should have a high renal excretion rate and thus ensure therapeutically effective drug levels in the urine. In this respect, the fluoroquinolones belong to the group of appropriate drugs to be used in cats. The relevance of therapeutical drug concentrations achievable in the urine is discussed for the example of marbofloxacin, a third-generation fluoroquinolone. New pharmacokinetic data showed that marbofloxacin concentrations of >= 2 mu g/ml are maintained in the urine of healthy cats for 72 and 103 hours after administration of 2 and 4 mg/kg BW s. c., respectively.