Subclinical bacteriuria is reported in up to 25-30% of cats, particularly those with predisposing factors such as chronic kidney disease, diabetes mellitus or hyperthyroidism. The diagnostic approach and treatment guidelines for feline subclinical bacteriuria are not always clear which can lead to the overuse of antimicrobial agents and thus the selection of multidrug-resistant bacteria.
This study reported the prevalence of subclinical bacteriuria in a population of 56 cats referred to Langford Vets Small Animal Hospital and described all cases of positive urine cultures as a series. Demographic data was collected for each cat and medical records were screened to identify any at-risk populations for subclinical bacteriuria or urinary tract infections. Routine urinalyses, including sediment examination and urine culture were performed on voided urine samples and cystocentesis samples. Proteomic techniques were utilised to identify a biomarker of infection or inflammation of the lower urinary tract. Finally, a method comparison study was conducted to investigate the effect of non-absorbent hydrophobic sand litter on the urine protein-to-creatinine ratio followed by a study comparing the effect of urine collection technique on common urinalysis parameters.
The prevalence of subclinical bacteriuria in this population was 4%. All affected cats were female and over 6 years old. Myeloperoxidase was identified in all cases of subclinical bacteriuria and urinary tract infection and so further studies exploring the utility of this enzyme as a biomarker seem justified. Non-absorbent hydrophobic sand litter did not interfere with urine protein-to-creatinine ratio measurements and agreement between the ratio determined from voided urine and cystocentesis samples appeared excellent for urine with an inactive sediment and urine protein-to-creatinine ratio <0.5. Bacterial growth was significantly more likely in voided samples compared to cystocentesis samples, p<0.0005, although this difference was not significant when accepted quantitative cut-off values for bacterial growth in urine were applied, p=0.5.