Molecular epidemiology of Enterobacter cloacae complex isolates with reduced carbapenem susceptibility recovered by blood culture

Jayathilake Sarangi; Nao Matsuo; Rina Nonogaki; Michiko Hayashi; Kumiko Kawamura; Masahiro Suzuki; Wanchun Jin; Kiyoko Tamai; Miho Ogawa; Jun-ichi Wachino; Kouji Kimura; Tetsuya Yagi; Yoshichika Arakawa

doi:10.7883/yoken.JJID.2021.141

This article has now been updated. Please use the final version.

Molecular epidemiology of Enterobacter cloacae complex isolates with reduced carbapenem susceptibility recovered by blood culture

Jayathilake Sarangi, Nao Matsuo, Rina Nonogaki, Michiko Hayashi, Kumiko Kawamura, Masahiro Suzuki, Wanchun Jin, Kiyoko Tamai, Miho Ogawa, Jun-ichi Wachino, Kouji Kimura, Tetsuya Yagi, Yoshichika Arakawa

Author information

Jayathilake Sarangi
Department of Bacteriology, Nagoya University Graduate School of Medicine, Japan
Nao Matsuo
Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Japan
Rina Nonogaki
Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Japan
Michiko Hayashi
Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Japan
Kumiko Kawamura
Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Japan
Masahiro Suzuki
Department of Microbiology, Fujita Health University, School of Medicine, Japan
Wanchun Jin
Department of Bacteriology, Nagoya University Graduate School of Medicine, Japan
Kiyoko Tamai
Miroku Medical Laboratory Co., Ltd., Japan
Miho Ogawa
Bio Medical Laboratories, Inc., Japan
Jun-ichi Wachino
Department of Bacteriology, Nagoya University Graduate School of Medicine, Japan
Kouji Kimura
Department of Bacteriology, Nagoya University Graduate School of Medicine, Japan
Tetsuya Yagi
Department of Infectious Diseases, Nagoya University Graduate School of Medicine, Japan
Yoshichika Arakawa
Department of Bacteriology, Nagoya University Graduate School of Medicine, Japan
Department of Medical Technology, Faculty of Medical Sciences, Shubun University, Japan

Keywords: Carbapenem-resistant Enterobacteriaceae, Enterobacter cloacae complex, whole-genome sequencing, bacteremia, Enterobacter roggenkampii

JOURNAL FREE ACCESS Advance online publication

Article ID: JJID.2021.141

DOI https://doi.org/10.7883/yoken.JJID.2021.141

The final version of this article is now available: Vol. 75 (2022), No. 1 pp. 41-48

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Abstract

The Enterobacter cloacae complex (ECC) is one of the most common causes of bacteremia and leads to poor clinical outcomes. The aim of this study was to clarify the antimicrobial susceptibility profiles and genetic backgrounds of non-carbapenemase-producing reduced-carbapenem-susceptible (RCS) ECC blood isolates in Japan using agar dilution antimicrobial susceptibility testing, whole-genome sequencing, and quantitative polymerase chain reaction for assays of ampC, ompC and ompF transcripts. Forty-two ECC blood isolates were categorized into RCS and carbapenem-susceptible groups based on imipenem minimum inhibitory concentration. RCS ECC blood isolates belonged to distinct species and sequence types and produced varying class C β-lactamases. The E. roggenkampii, E. asburiae, and E. bugandensis isolates belonged only to the RCS group. Some E. hormaecheii ssp. steigerwaltii isolates of the RCS group exhibited AmpC overexpression caused by amino acid substitutions in AmpD and AmpR along with ompF gene downregulation. These findings suggest that non-carbapenemase-producing RCS ECC blood isolates are genetically diverse.

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