[Development and Evaluation of Screening Culture Medium for Detection of Drug-Resistant Gram Negative Rods Containing Stealth Type CPE].

Abstract

There is a report that an infection by medicine resistant bacteria will be the number one cause of death in 2050 according to the recommendation of WHO, and the CPE (carbapenem-producing Enterobacteriaceae) infection is regarded as a problem in particular. When detecting CPE, it is important how to detect stealth type CPE sensitive to carbapenem series medicines. So we used the 2 types of screening culture medium, "KBM" CRE-JU culture medium ‹KOJINBAIO› (CRE-JU culture medium) and the FRPM culture medium, and tried to detect drug-resistant gram-negative bacilli such as CPE, stealth type CPE, ESBL-producing bacteria, and excess AmpC-producing bacteria (AmpC-producing bacteria), etc. in combination of this culture mediums. As a result, CRE-JU culture medium showed a difference in the growth of CPE depending on the amount of inoculated bacteria while β-lactamase non-producing strain and other strains except for high concentration ESBL-producing bacteria and AmpC-producing bacteria were un-growing. Most of the CRE, stealth type CPE, ESBL-producing bacteria and AmpC-producing bacteria grew in the FRPM culture medium while most of the β-lactamase non-producing strains with a MIC value of meropenem (MEPM) of 2 µg/mL or less were un-growing. From these results, it was suggested that when a strain grown on CRE-JU and FRPM culture mediums, it could be distinguished as CPE, and when strains grown on FRPM culture medium which were un-grown on CRE-JU culture medium, it could be distinguished as drug-resistant bacteria such as stealth type CPE, ESBL-producing bacteria, and AmpC-producing bacteria. When strains not grown on CRE-JU and FRPM culture mediums, it could be distinguished as sensitive.