Enterobacteriaceae
BacteriologyVariability in Zinc Concentration among Mueller-Hinton Broth Brands: Impact on Antimicrobial Susceptibility Testing of Metallo-β-Lactamase-Producing EnterobacteriaceaeZinc concentrations in cation-adjusted Mueller-Hinton broth (caMHB) from different manufacturers have been found to differ. Here, we evaluated the impact of utilizing different brands and lots of commercially available caMHB on the classification of the antimicrobial susceptibility of metallo-β-lactamase (MBL)-harboring Enterobacteriaceae. We also evaluated the addition of EDTA to caMHB as a means of achieving zinc-limited...
BacteriologyCorrelation between Broth Microdilution and Disk Diffusion Results when Testing Ceftazidime-Avibactam against a Challenge Collection of Enterobacterales Isolates: Results from a Multilaboratory StudyWe assessed the ceftazidime-avibactam disk diffusion breakpoints that provide the lowest discrepancy error rates by testing an Enterobacterales isolate collection with ceftazidime-avibactam MIC values near the breakpoints. Isolates (n = 112) were susceptibility tested by broth microdilution and disk diffusion methods in 3 laboratories. Current disk diffusion...
BacteriologyPhenotypic Detection of Plasmid-Mediated Colistin Resistance in EnterobacteriaceaeThe aim of this work was to evaluate an easy-to-perform assay based upon inhibition of mobile colistin resistance (MCR) activity by EDTA. We included 92 nonrelated isolates of Enterobacteriaceae (74 Escherichia coli, 17 Klebsiella pneumoniae, and 1...
BacteriologyImproved Species-Level Clinical Identification of Enterobacteriaceae through Broad-Range dnaJ PCR and SequencingEnterobacteriaceae represent a diverse and medically important family of bacteria that are difficult to identify to the species level using the standard molecular method of 16S rRNA gene sequencing. Prior work has demonstrated the value of dnaJ gene sequence analysis in resolving different members of the family. However, existing protocols are not optimized...
BacteriologyThe Role of fosA in Challenges with Fosfomycin Susceptibility Testing of Multispecies Klebsiella pneumoniae Carbapenemase-Producing Clinical IsolatesWith multidrug-resistant (MDR) Enterobacterales on the rise, a nontoxic antimicrobial agent with a unique mechanism of action such as fosfomycin seems attractive. However, establishing accurate fosfomycin susceptibility testing for non-Escherichia coli isolates in a clinical microbiology laboratory remains problematic. We evaluated fosfomycin susceptibility...
EpidemiologyGenomics for Molecular Epidemiology and Detecting Transmission of Carbapenemase-Producing Enterobacterales in Victoria, Australia, 2012 to 2016Carbapenemase-producing Enterobacterales (CPE) are being increasingly reported in Australia, and integrated clinical and genomic surveillance is critical to effectively manage this threat. We sought to systematically characterize CPE in Victoria, Australia, from 2012 to 2016.
BacteriologyDevelopment of Broth Microdilution MIC and Disk Diffusion Antimicrobial Susceptibility Test Quality Control Ranges for the Combination of Cefepime and the Novel β-Lactamase Inhibitor EnmetazobactamThird-generation cephalosporin resistance among Enterobacteriaceae, mediated by the spread of extended-spectrum β-lactamases (ESBLs), is a very serious medical concern with limited therapeutic options. Enmetazobactam (formerly AAI101) is a novel penicillanic sulfone β-lactamase inhibitor active against a wide range of ESBLs. The combination of enmetazobactam and...
BacteriologyReduced Incubation Time of the Modified Carbapenem Inactivation Test and Performance of Carbapenem Inactivation in a Set of Carbapenemase-Producing Enterobacteriaceae with a High Proportion of blaIMP IsolatesAccurate and timely identification of carbapenemase-producing Enterobacteriaceae (CPE) is critical for microbiology laboratories in order to facilitate infection prevention, reduce the spread of multiresistant Gram-negative bacilli, and reduce delays to effective antibiotic therapy. We undertook a study to compare the carbapenem inactivation method (CIM) against the...
