Comparative analysis of a rapid diagnostic test and scoring tools for ESBL detection in Enterobacterales bloodstream infections for optimizing antimicrobial therapy

Abstract

ABSTRACT Extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales bloodstream infections (BSI) are associated with increased cost, morbidity, and mortality compared with BSI by non-ESBL-producing bacteria. Phenotypic susceptibility data from blood cultures can take up to 72 hours to result, leading to delays in appropriate antimicrobial administration and unnecessary carbapenem usage. We sought to evaluate the performance of a rapid diagnostic test (RDT) and two published diagnostic scoring tools for predicting ceftriaxone resistance in BSI by Enterobacterales . This was a retrospective observational cohort study evaluating adult patients with BSI by select Enterobacterales species ( Escherichia coli , Klebsiella oxytoca , Klebsiella pneumoniae group, Proteus mirabilis , and Salmonella spp.). We compared the performance of a multiplex-PCR panel by BioFire (BCID2) with two diagnostic scoring tools for predicting ceftriaxone resistance. Among 356 patients, ceftriaxone resistance was observed in 41 of 356 (11.5%) isolates. BCID2 accurately predicted ceftriaxone susceptibility in 99.2% of isolates (92.7% sensitivity and 100% specificity), compared with <90% for the two scoring tools ( P < 0.05 for both). In ceftriaxone-resistant isolates ( n = 41), BCID2 led to fewer instances of undertreatment with ceftriaxone compared with scoring tools (7.3% vs 68.3% and 92.7%). In ceftriaxone-susceptible isolates ( n = 315), BCID2 led to no instances of overtreatment with carbapenems compared with 3.8% and 5.7% with the scoring tools. The BCID2 panel outperformed both ESBL scoring tools in our population. Local evaluation of RDT and scoring tools should be performed in conjunction with institutional implementation. IMPORTANCE Our study addresses a significant issue in the medical and scientific community—the delayed administration of appropriate antimicrobial treatments due to the time-consuming process of phenotypic susceptibility data collection in gram-negative bloodstream infections. Our research indicates that a multiplex PCR rapid diagnostic test (RDT) significantly outperformed two clinical scoring tools in predicting ceftriaxone susceptibility. Multiplex PCR also led to reduced instances of undertreatment with ceftriaxone and minimized overtreatment with carbapenems. Furthermore, multiplex PCR demonstrated high sensitivity and specificity in predicting ceftriaxone susceptibility. The results of our study underscore the potential RDTs to reduce the time to appropriate antimicrobial therapy, leading to improved patient outcomes and reduced healthcare costs.