Introduction
Urinary tract infections (UTIs) pose a significant global health challenge, commonly caused by Escherichia coli and other uropathogens. In addition to culture testing for UTI diagnosis, molecular and antigenic testing play a crucial role in early detection, leading to rapid results and an integrated diagnosis when paired with standard culture techniques. This study preliminary evaluates the efficacy of Urisponge™ for molecular and antigenic testing, an innovative boric acid-free device designed for collection, transport, and preservation of urine specimens.
Material and Methods
Compatibility with molecular diagnostics have been tested for:
- DNA stability: device inoculated with urine samples spiked with Neisseria gonorrhoeae (NG) and tested at different time points after storage (refrigerated, room temperature, and 35°C).
- Absence of Extraction Interferents: device inoculated with urine spiked with NG, then extracted using the PrepSEQ™ Express Nucleic Acid Extraction Kit (Thermo) and amplified using either the Qiagen Microbial DNA qPCR Assay kit or the Cepheid GeneXpert® System.
- Absence of PCR Inhibitors: performed by amplifying FluA RNA suspensions absorbed onto sponges.
Additionally, the compatibility of samples collected with Urisponge™ was assessed in combination with antigenic tests for Legionella pneumophila (TRU Legionella®, Meridian Bioscience) and Streptococcus pneumoniae (TRU Strep Pneumo, Meridian Bioscience) using spiked urine, following the manufacturer’s instructions.
Results
Urine samples in Urisponge™ do not hinder the extraction and amplification of nucleic acids from NG and FluA. The maximum difference in Ct values was 0.61, compared to reference. DNA stability after collection was successfully tested (ΔCt≤3.5): up to 1 week at 35°C, 3 weeks at room temperature (RT), and 6 weeks refrigerated. As comparator, samples stored at RT and 35°C without preservatives showed a higher increase in ΔCt values. Preliminary antigenic test data also demonstrated agreement between results from non-preserved urine and urine collected using the device.
Conclusion
Samples collected with Urisponge™ showed to be compatible with both molecular and antigenic testing. For molecular testing, the possibility to test samples using molecular tests with longer timeframes compared to culture-based tests could streamline the processing of samples that might be collected at decentralized points away from the laboratory conducting the test.