Evaluation of the Liofilchem rapid ESBL NP test for the detection of extended spectrum beta-lactamases in Enterobacteriacea in complicated urinary tract infections at Mulago Hospital using direct urine samples

Abstract

Introduction: There is a growing burden of UTIs complicated by drug resistant microorganisms. Antimicrobial resistance (AMR) is a growing global public health threat, with extended- spectrum beta-lactamase (ESBL) producing bacteria contributing significantly to this problem. The available diagnostic methods are time consuming and laborious delaying timely antimicrobial intervention. This rapid ESBL test kit holds promise in bridging this gap. This study aimed to assess the diagnostic performance of the Liofilchem Rapid ESBL NP test in detecting ESBL-producing bacteria directly from urine samples of patients with complicated urinary tract infections (cUTIs) at Mulago National Referral and Teaching Hospital (MNRH) in Kampala, Uganda. This kit has been used in previous studies to detect ESBL production from isolates with promising results. However, these results need at least 24-48hours to obtain results Aim: To determine the diagnostic performance (sensitivity, specificity, positive predictive value, negative predictive value and kappa agreement) of Liofilchem Rapid ESBL NP test for the detection of ESBL from direct urine samples in complicated urinary tract infections at Mulago National Referral Hospital compared to Kirby Bauer disk diffusion method.Methods: A cross-sectional study design was employed, involving 150 participants aged 18 years and above, suspected of having cUTIs. We compared the Liofilchem Rapid ESBL NP test with Kirby Bauer disk diffusion using combined disk test for ESBL detection. Ethical approval was sought from the Institutional Review Board of the School of Biomedical Sciences with approval number SBS-2024-532 and informed consent was obtained from all participants.Results: The key findings of this study reveal that the Liofilchem Rapid ESBL NP test had a sensitivity of 40% and a specificity of 88.46%, compared to the gold standard disk diffusion method. The positive predictive value (PPV) was 84.21%, indicating that when the test yields a positive result, there is a high likelihood that the patient indeed has an ESBL-producing organism. However, the negative predictive value (NPV) was much lower at 48.94%, which signifies that a negative result cannot reliably rule out the presence of ESBLs.Conclusion: While the Liofilchem ESBL NP test may be useful for confirming the presence of ESBL, it may miss a significant number of ESBL-producing isolates, limiting its effectiveness as a standalone diagnostic tool in clinical settings.