Enterobacteriaceae
Mechanisms of ResistanceA Novel Transferable Resistance-Nodulation-Division Pump Gene Cluster, tmexCD2-toprJ2, Confers Tigecycline Resistance in Raoultella ornithinolyticaWe recently identified a novel plasmid-mediated resistance-nodulation-division (RND)-type efflux pump gene cluster, tmexCD1-toprJ1, in Klebsiella pneumoniae that conferred resistance to multiple antimicrobials, including tigecycline. While homologs of tmexCD1-toprJ1 were found encoded in many other bacterial species in GenBank, their functions and...
Clinical TherapeuticsA Matched Case-Case-Control Study of the Impact of Clinical Outcomes and Risk Factors of Patients with IMP-Type Carbapenemase-Producing Carbapenem-Resistant Enterobacteriaceae in JapanIMP-type carbapenemase, found in various Gram-negative bacteria, has been increasingly detected worldwide. We aimed to study the outcomes and risk factors for acquisition of IMP-type carbapenemase-producing carbapenem-resistant Enterobacteriaceae (IMP-CRE), as this has not been evaluated in detail.
SusceptibilityIn Vitro Activity of Cefiderocol, a Siderophore Cephalosporin, against Multidrug-Resistant Gram-Negative BacteriaCefiderocol is a parenteral siderophore cephalosporin with a catechol-containing 3′ substituent. We evaluated its MICs against Gram-negative bacteria, using iron-depleted Mueller-Hinton broth. The panel comprised 305 isolates of Enterobacterales, 111 of Pseudomonas aeruginosa, and 99 of ...
PharmacologyPharmacodynamics of the Novel Metallo-β-Lactamase Inhibitor ANT2681 in Combination with Meropenem for the Treatment of Infections Caused by NDM-Producing EnterobacteriaceaeEnterobacteriaceae that produce metallo-β-lactamases (MBLs) are an emerging threat to public health. The metallo-β-lactamase inhibitor (MBLi) ANT2681 inhibits the enzymatic activity of MBLs through interaction with the dinuclear zinc ion cluster present in the active site that is common to these enzymes. ANT2681 is being codeveloped, with meropenem as the partner β-lactam, as a novel combination therapy for infections caused by...
Epidemiology and SurveillanceNational Surveillance of Antimicrobial Susceptibility of Bacteremic Gram-Negative Bacteria with Emphasis on Community-Acquired Resistant Isolates: Report from the 2019 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)A multicenter collection of bacteremic isolates of Escherichia coli (n = 423), Klebsiella pneumoniae (n = 372), Pseudomonas aeruginosa (n = 300), and...
Epidemiology and SurveillanceGenomic Study of blaIMI-Positive Enterobacter cloacae Complex in Singapore over a Five-Year Study PeriodThe blaIMI gene is rarely detected outside the Enterobacter genus. Genomic characterization of 87 blaIMI-positive Enterobacter cloacae complex members revealed that the largest phylogenomic clade was made up of E. cloacae subsp. cloacae (71.3...
Mechanisms of ResistanceA Genotype-Phenotype Correlation Study of SHV β-Lactamases Offers New Insight into SHV Resistance ProfilesThe SHV β-lactamases (BLs) have undergone strong allele diversification that has changed their substrate specificities. Based on 147 NCBI entries for SHV alleles, in silico mathematical models predicted 5 positions as relevant for the β-lactamase inhibitor (BLI)-resistant (2br) phenotype, 12 positions as relevant for the extended-spectrum BL (ESBL) (2be) phenotype, and 2 positions as related solely to the narrow-spectrum (2b)...
Mechanisms of ResistanceComplex Response of the CpxAR Two-Component System to β-Lactams on Antibiotic Resistance and Envelope Homeostasis in EnterobacteriaceaeThe Cpx stress response is widespread among Enterobacteriaceae. We previously reported a mutation in cpxA in a multidrug-resistant strain of Klebsiella aerogenes isolated from a patient treated with imipenem. This mutation yields a single-amino-acid substitution (Y144N) located in the periplasmic sensor domain of CpxA. In this work, we sought to...
Epidemiology and SurveillanceComparison of Commensal and Clinical Isolates for Diversity of Plasmids in Escherichia coli and Klebsiella pneumoniaeIn this study, the plasmid content of clinical and commensal strains was analyzed and compared. The replicon profile was similar in both populations, except for L, M, A/C, and N (detected only in clinical strains) and HI1 (only in commensal strains). Although I1 and F were the most frequent replicons, only IncI1, sequence type 12 (ST12) was associated with blaCMY-2 in both populations. In contrast, the widespread...
