In vitro activity of beta-lactam/beta-lactamase inhibitors, colistin, tigecycline, and eravacycline against carbapenemase-producing uropathogenic Enterobacterales.

AIMS: This study aimed to evaluate in vitro activity of β-lactam/β-lactamase inhibitor (BL/BLI) combinations, colistin, tigecycline, and eravacycline against carbapenemase producing Enterobacterales (CPE) uropathogens.

METHODS

This cross-sectional study included 162 urine samples from UTI patients. Enterobacterales isolates were identified using the Remel RapID ONE system. Minimum inhibitory concentrations (MICs) were determined using Sensititre panels, and carbapenemase genes (blaNDM, blaKPC, and blaOXA-48) were detected by PCR and confirmed by sequencing.

RESULTS

Of 162 urine samples, 120 (74.1%) were culture-positive, yielding 145 isolates, of which 117 (81%) were Enterobacterales. Carbapenem resistance was detected in 104/117 (89%) isolates, encoding blaNDM (45%), blaKPC (24%), and blaOXA-48 (30.7%). blaNDM harboring isolates were resistant to all tested BL/BLI combinations, whereas blaKPC and blaOXA-48 carrying isolates remained susceptible to CZA and IMR. blaKPC carrying pathogens were susceptible to MEV. Colistin, tigecycline, and eravacycline showed good activity against all isolates except Proteus mirabilis.

CONCLUSIONS

The efficacy of BL/BLI combinations is limited by the high prevalence of blaNDM producing pathogens. In contrast, blaKPC and blaOXA-48 encoding isolates remained susceptible against CZA and IMR while colistin, tigecycline, and eravacycline retained their activities. It highlighted the importance of molecular surveillance to guide appropriate therapy for CPE-associated UTIs.