[The Deveroppment of Screening Methods Using the Disk Diffusion Method for Carbapenemase-producing...

Carbapenem-resistant Enterobacteriaceae (CRE) are increasing globally. Particularly, carbapenemase-producing Enterobacteriaceae (CPE) are of concern. Rapid and accurate detection of these strains is critical for appropriate antimicrobial use and hospital infection control. In the present study, criteria for CPE screening were examined using a carbapenem susceptibility disk. Carbapenemase producers showed minimal inhibition zones for faropenem (5 μg): 6-12 mm (mean: 6.9 mm). Some strains with the IMP-6 genotype showed inhibition zones of >30 mm for imipenem (10 μg) and biapenem (10 μg). All strains that formed inhibition zones for FRPM had the IMP-6 genotype. The cut off values of carbapenemase-producers, determined by ROC analysis, were 12 mm for FRPM, 24 mm for meropenem (10 μg), 29 mm for BIPM, 25 mm for doripenem (10 μg), 26 mm for IPM, and 24 mm for panipenem (10 μg). Thus, the sensitivity was the highest (100%) for FRPM. Specificities were 93.44% for MEPM and DRPM and 85.25% for FRPM. Consequently, a drug sensitivity test using FRPM (5 μg) disks facilitates simple and accurate CPE screening.