The Antimicrobial Resistance Characteristics of Imipenem-Non-Susceptible, Imipenemase-6-Producing <i>Escherichia coli</i>
Reo Onishi,
Katsumi Shigemura,
Kayo Osawa,
Young-Min Yang,
Koki Maeda,
Shiuh-Bin Fang,
Shian-Ying Sung,
Kenichiro Onuma,
Atsushi Uda,
Takayuki Miyara,
Masato Fujisawa
Affiliations
Reo Onishi
Department of Public Health, Division of Infectious Diseases, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka Suma-ku, Kobe 654-0142, Japan
Katsumi Shigemura
Department of Public Health, Division of Infectious Diseases, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka Suma-ku, Kobe 654-0142, Japan
Kayo Osawa
Department of Medical Technology, Kobe Tokiwa University, 2-6-2 Otani-cho, Nagata-ku, Kobe 653-0838, Japan
Young-Min Yang
Division of Urology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
Koki Maeda
Division of Urology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
Shiuh-Bin Fang
Department of Pediatrics, Division of Pediatric Gastroenterology and Hepatology, Shuang Ho Hospital, Taipei Medical University, 291 Jhong Jheng Road, Jhong Ho District, New Taipei City 23561, Taiwan
Shian-Ying Sung
International Ph.D. Program for Translational Science, College of Medical Science and Technology, Taipei Medical University, Taipei 11031, Taiwan
Kenichiro Onuma
Department of Infection Control and Prevention, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
Atsushi Uda
Department of Infection Control and Prevention, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
Takayuki Miyara
Department of Infection Control and Prevention, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
Masato Fujisawa
Division of Urology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
Imipenemase-6 (IMP-6) type carbapenemase-producing Enterobacteriaceae is regarded as dangerous due to its unique lack of antimicrobial susceptibility. It is resistant to meropenem (MEPM) but susceptible to imipenem (IPM). In addition to carbapenemase, outer membrane porins and efflux pumps also play roles in carbapenem resistance by reducing the antimicrobial concentration inside cells. Extended-spectrum β-lactamase (ESBL) is transmitted with IMP-6 by the plasmid and broadens the spectrum of antimicrobial resistance. We collected 42 strains of IMP-6-producing Escherichia coli and conducted a molecular analysis of carbapenemase, ESBL, porin, efflux, and epidemiological characteristics using plasmid replicon typing. Among the 42 isolates, 21 strains were susceptible to IPM (50.0%) and 1 (2.4%) to MEPM. Seventeen strains (40.5%) co-produced CTX-M-2 type ESBL. We found that the relative expression of ompC and ompF significantly correlated with the MIC of IPM (p = 0.01 and p = 0.03, respectively). Sixty-eight% of CTX-M-2-non-producing strains had IncI1, which was significantly different from CTX-M-2-producing strains (p < 0.001). In conclusion, 50.0% of our IMP-6-producing strains were non-susceptible to IPM, which is different from the typical pattern and can be attributed to decreased porin expression. Further studies investigating other types of carbapenemase are warranted.
