Extended Spectrum Beta-Lactamases in Complicated Urinary Tract Infections

Objectives: Urinary tract infection (UTI) is one of the most common clinical conditions in adults who present at the emergency department and primary health centers1. UTIs may be life-threatening if not properly treated, and a variety of bacterial pathogens are associated with UTI including both gram-negative and some gram-positive bacteria2.
Antimicrobial resistance (AMR) is an increasing phenomenon by which uropathogens evade antimicrobial agents. An important example is the production of β-lactamases which is a major resistance mechanism used by some pathogens3. These organisms producing the Extended Spectrum β-lactamases (ESBLs) lead to resistance to penicillins, cephalosporins, and related compounds3. It is becoming increasingly difficult to treat these infections because of their high level of resistance4.
Studies in different regions of the world have reported varying prevalences of ESBL-producing pathogens ranging from 1.3% to 74%4, 5. According to a World Health Organization (WHO) report published in 2021, ESBL-producing Enterobacteriaceae (ESBL-EB) pose a high risk to public health and fall under the critical priority category of pathogens which new antibiotics are needed to manage6.

Methods: All results from a database of symptomatic adult (18+) patients’ urine specimens tested by Guidance® UTI between 07/01/2022 and 02/11/2024 and 2024 were retrospectively analyzed. All specimens were collected via either voiding or catheterization.
The ESBL phenotypic assay is performed when E. coli, Klebsiella, Enterobacter, Citrobacter, Proteus, Acinetobacter, or Pseudomonas species are detected. Guidance® UTI uses Multiplex-PCR (M-PCR) to detect several ESBL resistance genes.

Results: Out of 120,983 tests performed, the prevalence ESBL phenotypes was found to be 8.4% (n = 10,222). There was an 80.7% concordance between EBSL gene detection result and the phenotypic assay result.

Conclusions: ESBL-producing pathogens are important to public health because of the ever-increasing antimicrobial resistance, which is why the WHO has classified them as a critical priority. Fortunately, our US-based retrospective analysis of specimens from complicated UTIs indicated a relatively low (8.4%) prevalence of the ESBL phenotype, as well as a strong concordance (80.7%) between ESBL gene detection and phenotype.