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 assay, enterococci and some group B streptococci produce colonies in various shades of red onto the third, colourless, selective enterococcus agar. This special agar is a chromogenic agar which makes the interpretation of the results easier.
In the Uricult Trio assay, β-glucuronidase-producing organisms form colonies in various shades of brown or grey onto the third, colourless, selective E.coli agar. This special agar is a chromogenic agar which further assists the interpretation of results. The most common uropathogenic gram-negative bacteria are E. coli and Klebsiella pneumoniae(3). E. coli causes 70-95 % of UTIs(4).
- 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.
- Behzadi P, Behzadi E, Yazdanbod H, Aghapour R, Akbari Cheshmeh M, Salehian Omaran D. A survey on urinary tract infections associated with the three most common uropathogenic bacteria. Maedica, A Journal of Clinical Medicine, 2010; 5: 111-115.
- Stamm WE. An epidemic of urinary tract infections? The New England Journal of Medicine, 2001; 345: 1055-1057.