Multicenter interlaboratory study of routine systems for the susceptibility testing of temocillin using a challenge panel of multidrug-resistant strains

AbstractAccurate susceptibility result of temocillin (TMO) is important for treating infections caused by multidrug-resistantEnterobacterales. This multicenter study aimed to investigate the performance of routine temocillin testing assays againstEnterobacterales challenging strains.  Forty-seven selected clinical isolates were blindly analyzed by 12 Belgian laboratories using VITEK® 2 (n = 5) and BD Phoenix™ (n = 3) automated systems, ETEST® gradient strip (n = 3), and disk (3 brands) diffusion method (DD;n = 6) for temocillin susceptibility using standardized methodology. Results were interpreted using EUCAST 2023 criteria and compared to the broth microdilution (BMD; Sensititre™ panel) method used as gold standard. Methods’ reproducibility was assessed by testing 3 reference strains in tripl icate. A total of 702 organism-drug results were obtained against 33 TMO-susceptible and 14 TMO-resistant isolates. ExcludingProteae species (P. mirabilis andM. morganii), the essential agreement rates were excellent (91.5 –100%) for all MIC-based methods. The highest category agreement was achieved by ETEST® (97.5%) followed by VITEK® 2 (93.2%), disk diffusion (91.6%), and BD Phoenix™ (88.5%). BD Phoenix™ and paper disk diffusion overcalled resistance (11.5% and 6.8% of major discrepancies, respectively), whi le ROSCO tablets diffusion and VITEK® 2 generated higher very major discrepancies (7.1% and 4.2% respectively). Inter-assay reproducibility was...
Source: European Journal of Clinical Microbiology and Infectious Diseases - Category: Microbiology Source Type: research