Introduction
Urinary tract infections (UTIs) caused by uropathogens, particularly bacteria like Escherichia coli, are a global health concern. Accurate identification of the responsible agent is crucial for selecting appropriate antibiotic treatments. To enhance the diagnostic process, it is essential that intact urine samples reach the laboratory undamaged. This study aims to assess the effectiveness of Urisponge™, an innovative boric acid-free device designed for collecting, transporting, and preserving urine specimens intended for culture tests.
Material and Methods
Microorganisms from clinical specimens, including Enterococcus faecalis, Escherichia coli, and Providencia rettgeri, have been diluted to a concentration of 1.5 x 10^5 CFU/mL. Bacterial suspensions have been used to spike urine samples obtained from healthy donors (3 males, 1 female), including artificial urine as control sample as per CLSI M40-A2. Spiked samples have been used to inoculate a set of devices as follows:
- Time 0 (T0, N = 1)
- Room temperature for 48 hours (RT, N = 3)
- Refrigerated for 48 hours (N = 1)
Per each storage condition, 1μL of urine was extracted from sponges by centrifugation and plated on a CHROMID® CPS® plate to assess the microbial load at baseline and after 48 hours, simulating transport conditions. The data were reported in colony-forming units (CFU) and the difference in concentration compared to T0 (ΔLOG).
Results
Following 48 hours of incubation at room temperature (22-25°C) or refrigerated conditions (2-8°C), no negative cultures were detected. Bacterial cultures obtained from Urisponge-collected samples during the same 48-hour period at both room temperature and refrigerated conditions exhibited a difference compared to the initial measurement (T0) of no more than 0.4 Log10. Additionally, there was strong consistency between log10/ml values for samples stored at room temperature and those refrigerated (≤0.4 Log10).
Conclusion
Urisponge™ demonstrates its effectiveness in preserving UTI microorganisms, effectively controlling growth within a 48-hour period. By maintaining microbial loads and preventing overgrowth, Urisponge™ ensures precision in urine culture tests, an essential factor for accurate diagnoses of urinary tract infections.