Impact of Carbapenem Heteroresistance Among Multidrug-Resistant ESBL/AmpC-Producing Klebsiella pneumoniae Clinical Isolates on Antibiotic Treatment in Experimentally Infected Mice

• Published in: Infection and drug resistance Vol. 14; pp. 5639 - 5650
• Main Authors: Xiong, Yilin, Han, Yuqiao, Zhao, Zinan, Gao, Wenting, Ma, Yong, Jiang, Shiyu, Wang, Mengyao, Zhang, Qingqing, Zhou, Yun, Chen, Yang
• Format: Journal Article
• Language: English
• Published: New Zealand Dove Medical Press Limited 01.01.2021; Taylor & Francis Ltd; Dove; Dove Medical Press
• Subjects: Antibiotic resistance; Antibiotics; Antimicrobial agents; Bacterial infections; Bacterial pneumonia; Beta lactamases; Carbapenems; Clinical isolates; Drug resistance in microorganisms; enterobacteriaceae; Gel electrophoresis; Gene expression; heterogeneous susceptibility; Imipenem; in vivo; Klebsiella pneumoniae; Laboratory animals; Lethal dose; Multidrug resistance; Multidrug resistant organisms; Nosocomial infections; ompk porin; Original Research; Peritoneum; Peritonitis; Pneumonia; Population; Population studies; Pulsed-field gel electrophoresis; Reverse transcription; Strains (organisms); Subpopulations; treatment failure; Virulence; β Lactamase; China; in vivo; heterogeneous susceptibility; OmpK porin; imipenem; treatment failure; Enterobacteriaceae
• ISSN: 1178-6973; 1178-6973
• DOI: 10.2147/IDR.S340652

Antibiotic resistance is a growing health crisis that is further complicated by treatment failures caused by bacteria that exhibit heterogeneous susceptibility to antibiotics. The aim of this study was to describe imipenem (IPM)-heteroresistant strains among multidrug-resistant (MDR) ESBL/AmpC-producing clinical isolates, investigate their molecular phenotypic characteristics, and elucidate the outcome of antibiotic treatment in mice infected with the heteroresistant isolates. Antimicrobial susceptibility of isolates was determined by the disk diffusion and E-test methods. Heteroresistance to IPM was confirmed by population analysis profile (PAP) assays. PCR and sequencing were employed to detect MDR determinants. Molecular differences between the susceptible and resistant subpopulations were evaluated by sequencing and quantitative real-time reverse transcription PCR (qRT-PCR) analysis. The effect of the carbapenem-heteroresistant strains on antibiotic treatment was assessed using a mouse model of peritonitis with heteroresistant and subsequent treatment with IPM. In total, 37 MDR ESBL/AmpC-producing clinical isolates of were identified between September 2018 and December 2019. These strains were notably resistant to conventional antimicrobials other than carbapenems. Among the isolates, three strains exhibited heteroresistance to IPM and carried several ESBL and/or AmpC genes. Mice infected with a lethal dose of any of the three heteroresistant isolates were unable to survive in the presence of IPM treatment, as the percentage of the IPM-resistant subpopulation of each strain was increased in the peritoneum of these mice at 24 h after infection. The resistant subpopulation of the strains presented pulsed-field gel electrophoresis (PFGE) profiles that were identical to those of the susceptible subpopulation, but porin showed a reduction in gene expression (0.09- to 0.50-fold) in the resistant subpopulation. Carbapenem-heteroresistant strains were present among the MDR isolates producing ESBL/AmpC β-lactamases, and these heteroresistant strains failed IPM therapy in experimentally infected mice.