Performance evaluation of BrillianceTM UTI and Blood Agar Base No. 2 biplates for clinical urinary tract infection diagnosis

Urinary tract infection (UTI) is one of the most common bacterial infections globally, affecting individuals of all ages. Women are at higher risk, and it is estimated that half of all women will experience a UTI in their lifetime. Diagnosis and antibiotic susceptibility testing commonly rely on inoculation onto agar plates. Biplates, which contain two different media in one plate, may streamline this process. This study aimed to evaluate whether biplates improve diagnostic efficiency for UTIs. Biplates were manually poured using a peristaltic pump. BrillianceTM UTI agar and Blood Agar Base No. 2 were prepared per the manufacturer’s instructions. Plates were pretested using Enterobacter cloacae, Enterococcus faecalis, Escherichia coli, Proteus mirabilis, Staphylococcus aureus, Sptreptococcus pneumoniae and Streptococcus pyogenes to ensure accurate readings. Plates were read the next day using reference tables based on bacterial growth and clinical data. Twenty catheter samples, 23 midstream urine samples, one from another location, and six single-use catheters samples were analyzed. E. coli, E. faecalis and Klebsiella oxytoca/variicola were the most common UTI pathogens. McNemar’s test, with and without Yates´ correction for small sample sizes, showed no statically significant difference between the biplates and the regular agar plates. Biplates provide diagnostic accuracy equivalent to that of full-agar plate. However, the main advantage lies in cost-efficiency, as biplates are less expensive and present an opportunity for significant financial savings.