Intravesical compartments in the bladder can affect microbiological culturing outcome: An experimental study in pigs

Abstract

Urinary tract infections (UTIs) are one of the most common bacterial infections worldwide. The diagnosis is mainly dependent on the quantitative identification of uropathogens in urine from suspected patients and therefore, it is essential that bacterial count in urine specimens accurately reflects the bacterial population inside the bladder. In this study, we collected the first- and last urine specimens during a single full voiding from pigs with experimentally induced UTI and compared the urine density and bacterial counts of the collected specimens. We found that specimens from the same voiding varied in density and in bacterial counts by up to a thousand-fold with significant impact on diagnostic sensitivity. In conclusion, the porcine bladder can simultaneously contain intravesical compartments of varying density and bacterial counts that greatly influences microbiological analysis. The distribution of bacteria in intravesical compartments is critical to consider when using pigs as biomedical models of UTI. Furthermore, the similarities of porcine and human anatomy and physiology, suggest that the results are likely to be translatable to human, in which case potential UTIs could be overlooked by today’s diagnostic procedures.