Infrared vibrational spectroscopy: a rapid and novel diagnostic and monitoring tool for cystinuria

Cystinuria is the commonest inherited cause of nephrolithiasis (~1% in adults; ~6% in children) and is the result of impaired cystine reabsorption in the renal proximal tubule. Cystine is poorly soluble in urine with a solubility of ~1 mM and can readily form microcrystals that lead to cystine stone formation, especially at low urine pH. Diagnosis of cystinuria is made typically by ion-exchange chromatography (IEC) detection and quantitation, which is slow, laboursome and costly. More rapid and frequent monitoring of urinary cystine concentration would significantly improve the diagnosis and clinical management of cystinuria. We used attenuated total reflection - Fourier transform infrared spectroscopy (ATR-FTIR) to detect and quantitate insoluble cystine in 22 cystinuric and 5 healthy control urine samples. Creatinine concentration was also determined by ATR-FTIR to adjust for urinary concentration/dilution. Urine was centrifuged, the insoluble fraction re-suspended in 5 μL water and dried on the ATR prism. Cystine was quantitated using its 1296 cm−1 absorption band and levels matched with parallel measurements made using IEC. ATR-FTIR afforded a rapid and inexpensive method of detecting and quantitating insoluble urinary cystine. This proof-of-concept study provides a basis for developing a high-throughput, cost-effective diagnostic method for cystinuria, and for point-of-care clinical monitoring

Simple and rapid sample preparation system for the molecular detection of antibiotic resistant bacteria in human urine

Antibiotic resistance in urinary tract infections (UTIs) can cause significant complications without quick detection and appropriate treatment. . We describe a new approach to capture, concentrate and prepare amplification-ready DNA from antibiotic resistant bacteria in human urine samples. Klebsiella pneumoniae NCTC13443 (blaCTX-M-15 positive) spiked into filtered human urine was used as a model system. Bacteria were captured using anion exchange diaethylaminoethyl (DEAE) magnetic microparticles and concentrated 200-fold within ~3.5 minutes using a custom, valve-less microfluidic chip. Eight samples were processed in parallel, and DNA, was released using heat lysis from an integrated resistive heater. The crude cell lysate was used for real time Recombinase Polymerase Amplification (RPA) of the blaCTX-M-15 gene. The end to end processing time was approximately 15 minutes with a limit of detection of 1000 bacteria in 1 mL urin