Comparison of testing methods assessing the in vitro efficacy of the combination of aztreonam with avibactam on multidrug-resistant Gram-negative bacilli.

Background: Aztreonam-avibactam (ATM-AVI) combination shows promising effectiveness on most carbapenemase-producing Gram-negatives, yet standardized antibiotic susceptibility testing (AST) methods for evaluating the combination in clinical laboratories is lacking. We aimed to evaluate different ATM-AVI AST approaches.

Methods: 96 characterized carbapenem-resistant clinical isolates belonging to 9 Enterobacterales (EB; n = 80) and P.

Characterization of hypervirulent Klebsiella pneumoniae isolates in Belgium.

Hypervirulent Klebsiella pneumoniae (hvKp) raised concern worldwide. We studied 22 hvKp clinical invasive isolates referred to the Belgian national reference laboratory between 2014 and 2020. Sixty-four percent of the isolates expressed K2 capsular serotype and belonged to 7 different MLST lineages, while 32% expressed K1 (all belonging to ST23) and were associated with liver abscesses.

Rapid COVID-19 antigenic tests: Usefulness of a modified method for diagnosis.

The current reliable recommended test for coronavirus disease 2019 (COVID-19) diagnosis is quantitative reverse-transcription polymerase chain reaction (RT-qPCR). Rapid antigen test devices could be useful as they are less expensive, faster without the need of specialized laboratories to perform the test. We report the performances of two rapid immunochromatographic antigen testing devices compared with RT-qPCR for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection in nasopharyngeal samples.

Comparison of two multiplex immunochromatographic assays for the rapid detection of major carbapenemases in Enterobacterales.

Objectives: Two commercially available lateral flow immunochromatographic assays (ICAs) for detection of the major carbapenemases were prospectively assessed for the detection of carbapenemases in Enterobacterales: RESIST-4 O.K.N.

Evaluation of the RESIST-4 K-SeT assay, a multiplex immunochromatographic assay for the rapid detection of OXA-48-like, KPC, VIM and NDM carbapenemases.

Objectives: Accurate and fast identification of carbapenemase producers is essential for optimal patient management. Here, a new lateral flow immunochromatographic RESIST-4 K-SeT assay was assessed for the detection of carbapenemases in Enterobacteriaceae and non-fermenters.

Methods: The RESIST-4 K-SeT assay targets OXA-48-like, KPC, VIM and NDM, but not IMP carbapenemases.

Evaluation of the ePlex Blood Culture Identification Panels for Detection of Pathogens in Bloodstream Infections.

Rapid identification and susceptibility testing results are of importance for the early appropriate therapy of bloodstream infections. The ePlex (GenMark Diagnostics) blood culture identification (BCID) panels are fully automated PCR-based assays designed to identify Gram-positive and Gram-negative bacteria, fungi, and bacterial resistance genes within 1.5 h from positive blood culture.

OXA-427, a new plasmid-borne carbapenem-hydrolysing class D β-lactamase in Enterobacteriaceae.

Objectives: To describe a novel plasmid-borne class D carbapenemase (CHDL) named OXA-427 identified in several Enterobacteriaceae clinical isolates from nine patients in one Belgian hospital.

Methods: OXA-427-producing isolates were analysed by an electrochemical imipenem hydrolysis method (BYG Carba test), Carba NP test, conventional phenotypic assays and by molecular methods (PCR, whole sequencing of the OXA-427-encoding plasmid and cloning). The antimicrobial resistance profile of OXA-427 was analysed by expression of the cloned gene in Escherichia coli DH10B and J53.

Prospective evaluation of the OKN K-SeT assay, a new multiplex immunochromatographic test for the rapid detection of OXA-48-like, KPC and NDM carbapenemases.

Objectives: There is an urgent need for accurate and fast diagnostic tests capable of identifying carbapenemase producers. Here, we assessed the performance of a new multiplex lateral flow assay (OKN K -SeT) for the rapid detection of OXA-48-like, KPC and NDM carbapenemase-producing Enterobacteriaceae from culture colonies.

Methods: Two hundred collection isolates with characterized β-lactamase content and 183 non-duplicate consecutive isolates referred to two National Reference Centres over a 2 month period in 2016 were used to evaluate the OKN K -SeT assay.

Evaluation of a DNA microarray for rapid detection of the most prevalent extended-spectrum β-lactamases, plasmid-mediated cephalosporinases and carbapenemases in Enterobacteriaceae, Pseudomonas and Acinetobacter.

The dissemination of Gram-negative bacteria (GNB) producing extended-spectrum β-lactamases (ESBLs), plasmid-encoded cephalosporinases (pAmpCs) and carbapenemases is a matter of great clinical concern. In this study, we evaluated a new low-density DNA array 'Check-MDR CT103 XL' (Check-Points, Wageningen, The Netherlands) that identifies the most clinically relevant β-lactamase genes of ESBLs (blaTEM, blaSHV, blaCTX-M, blaBEL, blaPER, blaGES and blaVEB), pAmpCs (blaCMY-2-like, blaDHA, blaFOX, blaACC-1, blaACT/MIR and blaCMY-1-like/MOX) and carbapenemases (blaKPC, blaOXA-48, blaVIM, blaIMP, blaNDM, blaGIM, blaSPM and blaOXA-23, -24 and -58) in cultured bacteria. In total, 223 GNB isolates with well-characterised resistance mechanisms to β-lactams were analysed.

Evaluation of two new commercial immunochromatographic assays for the rapid detection of OXA-48 and KPC carbapenemases from cultured bacteria.

Background: Rapid detection and confirmation of carbapenemases remains very challenging for diagnostic laboratories.

Objectives: The objective of this study was to assess the performance of two new immunochromatographic (IC) commercial assays for the rapid detection of OXA-48-producing and KPC-producing Enterobacteriaceae in pure bacterial isolates.

Methods: A panel of 92 bacterial isolates predominantly including carbapenem-non-susceptible Enterobacteriaceae with previously defined carbapenem resistance mechanisms was tested.

Gene expression silencing with 'specific' small interfering RNA goes beyond specificity - a study of key parameters to take into account in the onset of small interfering RNA off-target effects.

RNA-mediated gene silencing (RNA interference) is a powerful way to knock down gene expression and has revolutionized the fields of cellular and molecular biology. Indeed, the transfection of cultured cells with small interfering RNAs (siRNAs) is currently considered to be the best and easiest approach to loss-of-function experiments. However, several recent studies underscore the off-target and potential cytotoxic effects of siRNAs, which can lead to the silencing of unintended mRNAs.

An evaluation of a low-density DNA microarray using cytochrome P450 inducers.

The aim of this study was to validate a low-density DNA microarray "Rat HepatoChip", which contains 59 genes from a range of potential toxic markers and drug metabolism-related genes. Liver mRNA was isolated from rats dosed with six different chemicals, dexamethasone, troleandomycin, miconazole, clotrimazole, and methylclofanapate, which are all known to induce different cytochrome P450 genes, and isoniazid, which does not cause histopathological changes. Replicate microarrays were used to measure the variability in the chips and in the process.

Use of a low-density microarray for studying gene expression patterns induced by hepatotoxicants on primary cultures of rat hepatocytes.

In the field of gene expression analysis, DNA microarray technology is having a major impact on many different areas including toxicology. For instance, a number of studies have shown that transcription profiling can generate the information needed to assign a compound to a mode-of-action class. In this study, we investigated whether compounds inducing similar toxicological endpoints produce similar changes in gene expression.

Gene expression profiling of drug metabolism and toxicology markers using a low-density DNA microarray.

DNA microarrays are useful tools to study changes of gene expression in response to a treatment with drugs. Here, we describe the optimization of conditions for the cDNA synthesis and hybridization protocols to be used for a low-density DNA microarray called 'Rat HepatoChips.' This DNA microarray with 59 carefully selected genes could be used to study changes in gene expression levels due to a treatment with xenobiotic.