Urinary tract infection (UTI) is one of the most common infections caused by bacteria(1). It is important to verify and treat UTI adequately since untreated UTI may cause kidney damage. Bacterial culture of an appropriately collected and handled urine sample can provide an accurate diagnosis. However, transportation of urine samples from the sample collection site to a laboratory may lead to incorrect results as bacteria may multiply if the samples are not transported correctly(2).
The Uricult tests are dipslides for culturing urine samples. The slides are covered on both sides with agar media, two or three media depending on the test. The slide can be dipped into urine, or urine can be poured onto the slide. Thereafter, the inoculated slide is inserted back into the tube, making it ready for incubation or for transportation. After incubation, the presence of bacteria is evidenced by colonies growing on the agar surface. The number of colonies indicates the number of colony forming units (CFU/ml) in the urine sample because each colony is the result of multiplication of a single bacterial cell.
The total colony count on all Uricult tests is determined from the originally green CLED agar by matching the colony density with the model chart. The bacteria may be classified as lactose fermenting or non-lactose fermenting bacteria based on their appearance on CLED agar. The number of gram-negative bacteria can be determined for all Uricult tests from the originally brownish–red, selective MacConkey agar.
In the Uricult Plus test, the colourless medium is selective for enterococcus. It helps to differentiate enterococcus that grows in various shades of red on the medium. Also group B streptococci may grow on this medium in small colonies.
In the Uricult Trio test, the colourless chromogenic E. coli medium is selective for β-glucuronidase-producing organisms. Especially E. coli grows in various shades of brown or grey on this medium. With this combination of three different media, Uricult Trio is a highly reliable tool for the identification of E. coli directly in primary urine cultures(3).
The predominant uropathogenic gram-negative bacterium that is causing 80 % of uncomplicated UTI cases is E. coli(4). The other bacteria commonly causing UTIs are Staphylococcus saprophyticus (10-15 %), Klebsiella, Enterobacter, and Proteus species.
- Centers for Disease Control and Prevention (CDC). Urinary tract infection, Available at: https://www.cdc.gov/getsmart/community/for-patients/common-illnesses/uti.html. Published 2015. Accessed 4 July 2017.
- Eisinger SW, Schwartz M, Dam L, Riedel S.Evaluation of the BD Vacutainer Plus Urine C&S preservative tubes compared with nonpreservative urine samples stored at 4°C and room temperature. Am J Clin Pathol 2013;140:306-313.
- Larinkari U, Rautio M. Evaluation of a new dipslide with a selective medium for the rapid detection of beta-glucuronidase-positive Escherichia coli. Eur. J. Clin. Microbiol. Infect. Dis. 1995; 14: 606-609.
- Ronald A. The etiology of urinary tract infection: traditional and emerging pathogens. Dis Mon 2003; 49: 71-82.