Comparison of collection techniques for quantitative urine culture in dogs

The degree of bacterial contamination of 75 urine samples collected by voluntary voiding, catheterization, and cystocentesis was studied in 25 clinically normal dogs (14 females and 11 males) to evaluate the suitability of quantitative urine culture for diagnosis or urinary tract infection. Significant bacteriuria (greater than 100,000/ml) was not observed. Insignificant bacteriuria presumably caused by urethrogenital contaminants was detected in 44% of the urine samples collected by voluntary voiding, in 20% of the samples collected by catheterization, and in 12% of the samples collected by cystocentesis. The urine was sterile in 40% of the samples collected by voluntary voiding, in 80% of the samples collected by catheterization, and in 84% of the samples collected by cystocentesis. A bacteria count suggestive of bacteriuria (10,000--100,000/ml) was obtained in 1 sample collected by cystocentesis but was attributed to inadvertent penetration of a loop of intestine. Low bacteria counts were obtained in 4 (16%) samples collected by voluntary voiding, presumably as a result of urethrogenital and integumentary bacterial contaminants. It was concluded that urine samples properly collected from dogs by voluntary voiding, catheterization, or cystocentesis are suitable for detection of significant bacteriuria.