Preferred β-lactone synthesis can explain high rate of false-negative results in the detection of OXA-48-like carbapenemases.

The resistance to carbapenems is usually mediated by enzymes hydrolyzing β-lactam ring. Recently, an alternative way of the modification of the antibiotic, a β-lactone formation by OXA-48-like enzymes, in some carbapenems was identified. We focused our study on a deep analysis of OXA-48-like-producing Enterobacterales, especially strains showing poor hydrolytic activity.

Evidence of an epidemic spread of KPC-producing Enterobacterales in Czech hospitals.

The aim of the present study is to describe the ongoing spread of the KPC-producing strains, which is evolving to an epidemic in Czech hospitals. During the period of 2018-2019, a total of 108 KPC-producing Enterobacterales were recovered from 20 hospitals. Analysis of long-read sequencing data revealed the presence of several types of bla-carrying plasmids; 19 out of 25 bla-carrying plasmids could be assigned to R (n = 12), N (n = 5), C (n = 1) and P6 (n = 1) incompatibility (Inc) groups.

Three-Dimensional Printed Target Plates for Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry.

Three-dimensional printing (3D printing) is a fast-growing technology with high impact in industry, medicine, and the life sciences. Fused deposition modeling (FDM), which uses plastic filaments extruded through a heated nozzle, is the most common 3D printing technology for creation of objects. In this work, the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) target plates printed by FDM technology using conductive plastic material were evaluated for their detection capability of proteins and peptides.

Molecular Characterization of OXA-48-Like-Producing Enterobacteriaceae in the Czech Republic and Evidence for Horizontal Transfer of pOXA-48-Like Plasmids.

The aim of this study was to characterize the first cases and outbreaks of OXA-48-like-producing Enterobacteriaceae recovered from hospital settings in the Czech Republic. From 2013 to 2015, 22 Klebsiella pneumoniae isolates, 3 Escherichia coli isolates, and 1 Enterobacter cloacae isolate producing OXA-48-like carbapenemases were isolated from 20 patients. Four of the patients were colonized or infected by two or three different OXA-48-like producers.

Characterization of pKP-M1144, a Novel ColE1-Like Plasmid Encoding IMP-8, GES-5, and BEL-1 β-Lactamases, from a Klebsiella pneumoniae Sequence Type 252 Isolate.

IMP-8 metallo-β-lactamase was identified in Klebsiella pneumoniae sequence type 252 (ST252), isolated in a Portuguese hospital in 2009. blaIMP-8 was the first gene cassette of a novel class 3 integron, In1144, also carrying the blaGES-5, blaBEL-1, and aacA4 cassettes. In1144 was located on a ColE1-like plasmid, pKP-M1144 (12,029 bp), with a replication region of limited nucleotide similarity to those of other RNA-priming plasmids, such as pJHCMW1.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry meropenem hydrolysis assay with NH4HCO3, a reliable tool for direct detection of carbapenemase activity.

A comparison of a matrix-assisted laser desorption ionization-time of flight mass spectrometric (MALDI-TOF MS) meropenem hydrolysis assay with the Carba NP test showed that both methods exhibited low sensitivity (approximately 76%), mainly due to the false-negative results obtained with OXA-48-type producers. The addition of NH4HCO3 to the reaction buffer for the MALDI-TOF MS assay dramatically improved its sensitivity (98%). Automatic interpretation of the MALDI-TOF MS assay, using the MBT STAR-BL software, generally agreed with the results obtained after manual analysis.

Detection of OXA-48-type carbapenemase-producing Enterobacteriaceae in diagnostic laboratories can be enhanced by addition of bicarbonates to cultivation media or reaction buffers.

Carbapenemase-mediated resistance to carbapenems in Enterobacteriaceae has become the main challenge in the treatment and prevention of infections recently. The partially unnoticed spread of OXA-48-type carbapenemase producers is usually assigned to low minimum inhibitory concentrations (MICs) of carbapenems that OXA-48-producing isolates often display. Therefore, there is an urgent need of specific and sensitive methods for isolation and detection of OXA-48 producers in clinical microbiology diagnostics.

High prevalence of ST131 among CTX-M-producing Escherichia coli from community-acquired infections, in the Czech Republic.

A total of 2,683 nonrepetitive Escherichia coli isolates were collected from microbiological laboratories covering all regions of the Czech Republic, during April 2011. Antimicrobial susceptibility patterns of E. coli were assessed.

Detection of NDM-1, VIM-1, KPC, OXA-48, and OXA-162 carbapenemases by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a potentially useful tool for the detection of antimicrobial resistance, especially that conferred by β-lactamases. Here we describe a modification of a previously reported MALDI-TOF MS meropenem hydrolysis assay. The modified method was validated on 108 carbapenemase-producing members of the Enterobacteriaceae, two NDM-1-producing Acinetobacter baumannii isolates, and 35 carbapenem-resistant enterobacteria producing no carbapenemase.

KPC-2-producing Klebsiella pneumoniae isolated from a Czech patient previously hospitalized in Greece and in vivo selection of colistin resistance.

Carbapenemase-producing Gram-negative bacteria peak clinical interest due to their ability to hydrolyze most β-lactams, including carbapenems; moreover, their genes spread through bacterial populations by horizontal transfer. Bacteria with acquired carbapenemase have sporadically been reported in the Czech Republic, so far only in Enterobacteriaceae and Pseudomonas aeruginosa. In this study, we described the first finding of a KPC-2-producing strain of Klebsiella pneumoniae, which was isolated from a surgical wound swab, decubitus ulcer, and urine of a patient previously hospitalized in Greece.

Carbapenemase activity detection by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry is used for the determination of molecular weights of different chemical compounds. We describe here the use of MALDI-TOF mass spectrometry to detect a carbapenem antibiotic, meropenem, and its degradation products. Buffered meropenem solution (0.