Published in:
Open Access
01-12-2017 | Research article
Development of selective medium for IMP-type carbapenemase-producing Enterobacteriaceae in stool specimens
Authors:
Norihisa Yamamoto, Ryuji Kawahara, Yukihiro Akeda, Rathina Kumar Shanmugakani, Hisao Yoshida, Hideharu Hagiya, Naohiro Hara, Isao Nishi, Satomi Yukawa, Rumiko Asada, Yumi Sasaki, Kazuhiro Maeda, Noriko Sakamoto, Shigeyuki Hamada, Kazunori Tomono
Published in:
BMC Infectious Diseases
|
Issue 1/2017
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Abstract
Background
Identification of carbapenemase-producing Enterobacteriaceae (CPE) in faecal specimens is challenging. This fact is particularly critical because low-level carbapenem-resistant organisms such as IMP-producing CPE are most prevalent in Japan. We developed a modified selective medium more suitable for IMP-type CPE.
Methods
Fifteen reference CPE strains producing different types of β-lactamases were used to evaluate the commercially available CHROMagar KPC and chromID CARBA as well as the newly prepared MC-ECC medium (CHROMagar ECC supplemented with meropenem, cloxacillin, and ZnSO4) and M-ECC medium (CHROMagar ECC supplemented with meropenem and ZnSO4). A total of 1035 clinical samples were then examined to detect CPE using chromID CARBA and M-ECC medium.
Results
All tested strains producing NDM-, KPC-, and OXA-48-carbapenemases were successfully cultured in the media employed. Although most of the IMP-positive strains did not grow in CHROMagar KPC, chromID CARBA, or MC-ECC, all tested strains grew on M-ECC. When faecal samples were applied to the media, M-ECC medium allowed the best growth of IMP-type CPE with a significantly higher sensitivity (99.3%) than that of chromID CARBA (13.9%).
Conclusions
M-ECC medium was determined as the most favourable selective medium for the detection of IMP-type CPE as well as other types of CPE.