Rapid Phenotypic Antibiotic Susceptibility Determination Direct From Spiked Urine Samples Shows Strong Correlation with Gold Standard for Urinary Tract Infection

GeneCapture is developing a groundbreaking, point-of-care antibiotic susceptibility testing (AST) technique that can provide results within 2 hours directly from raw urine samples. This innovative method represents a major leap forward in diagnosing urinary tract infections (UTIs).

To validate the new technique, researchers employed a panel of uropathogen isolates obtained from clinical specimens with confirmed UTIs from various laboratories across the southern United States. These isolates, primarily Escherichia coli, were spiked into fresh clean-catch urine samples to create mock samples representing diverse antibiotic responses.

The study tested 20 strains of E. coli, the causative agent in over 80% of UTIs, alongside 6 strains each of Klebsiella pneumoniae and Proteus mirabilis, the next most prevalent UTI causes. Each strain was evaluated against susceptible, intermediate, and resistant breakpoints of up to 5 appropriate antibiotics, including Amoxicillin-Clavulanate, Cefpodoxime, Ciprofloxacin, Nitrofurantoin, and Trimethoprim-Sulfamethoxazole.

The novel method measures susceptibility by comparing bacterial growth responses to antibiotics at these critical concentration thresholds, rather than relying on traditional culturing methods. Remarkably, exposing the bacteria to these drugs for just 90 minutes yielded a 98% agreement with the gold standard culture results across 247 bacteria/antibiotic pairs.

Furthermore, testing the same strains on separate days in triplicate demonstrated a reproducibility rate of 97%, underscoring the assay's reliability. The sequential steps of this groundbreaking AST process - sample processing, growth, labeling, and counting - can be easily automated using a cartridge currently under development.

This laboratory-based study demonstrates the immense potential of GeneCapture's rapid, phenotypic AST technique in revolutionizing UTI diagnosis and antibiotic stewardship.