Direct Testing for KPC-Mediated Carbapenem Resistance from Blood Samples Using a T2 Magnetic Resonance Based Assay

Abstract

Molecular-based carbapenem resistance testing in Gram-negative bacterial bloodstream infections (BSIs) is currently limited because of the reliance on positive blood culture (BC) samples. The T2Resistance™ panel may now allow the detection of carbapenemase- and other β-lactamase encoding genes directly from blood samples. We detected carbapenem resistance genes in 11 (84.6%) of 13 samples from patients with BC-documented BSIs (10 caused by KPC-producing Klebsiellapneumoniae and 1 caused by VIM/CMY-producing Citrobacter freundii). Two samples that tested negative for carbapenem resistance genes were from patients with BC-documented BSIs caused by KPC-producing K. pneumoniae who were receiving effective antibiotic therapy. In conclusion, our findings suggest that the T2Resistance™ panel can be a reliable tool for diagnosing carbapenem-resistant Gram-negative bacterial BSIs.

Prospective observational pilot study of the T2Resistance panel in the T2Dx system for detection of resistance genes in bacterial bloodstream infections

“…Bloodstream infections were classified based on previously established criteria ( 15 , 16 ). Proven BSIs were defined as a T2B positive and/or positive BC using a concurrently drawn specimen.…”

T2Bacteria and T2Resistance Assays in Critically Ill Patients with Sepsis or Septic Shock: A Descriptive Experience

“…The T2Bacteria and T2Resistance assays are rapid molecular tests performed on whole blood that exploit T2 Magnetic Resonance (T2MR ® ) technology (T2Biosystems, Lexington, MA, USA) [ 13 , 14 , 15 , 16 ]. This technology allows the detection of the agglomeration of superparamagnetic particles induced by the amplicons, thereby leading to the identification of different bacteria with the T2Bacteria assay ( Enterococcus faecium , Staphylococcus aureus , Klebsiella pneumoniae , Pseudomonas aeruginosa , Acinetobacter baumannii , and Escherichia coli ) and of different resistance determinants with the T2Resistance assay (bla KPC , bla OXA-48 , bla NDM , bla VIM , bla IMP , bla CTX-M-14/15 , bla CMY , bla DHA , vanA/B, mecA/C), within 3–5 h after the blood draw [ 13 , 17 , 18 ].…”

Rapid, Ultrasensitive, and Visual Detection of Pathogens Based on Cation Dye-Triggered Gold Nanoparticle Electrokinetic Agglutination Analysis

“…8 Genotypic assays can identify bacteria as well as acquire results of AST by detecting resistance genes, bypassing the need for lengthy culture and incubation, 9 such as coated-silicon hybridization-based biosensor, 10 colorimetric nanodiagnostic platform, 11 fluorescence biosensor, 12 photoelectrochemical assay, 13 solid-phase polymerase chain reaction (SP-PCR), 14 and the new commercial tests such as BioFire FilmArray blood culture identification panel and T2Magnetic Resonance-based assay. 15,16 Nonetheless, genotypic AST has limitations, such as the inability to identify strains with unclear gene mutations, and the presence of antibiotic resistance genes is not always consistent with phenotypic AST. 17,18 Phenotypic-based AST can determine bacterial growth with exposure to antibiotics and provide more convincing AST results, such as digital PCR, 19,20 digital real-time loop-mediated isothermal amplification (dLAMP), 21 optical microscopy, 22 microfluidic chip, 8,23−29 electrochemical biosensor, 30,31 chemiluminescence sensor, 32 Raman spectrometry, 33−35 gold nanoparticle (AuNP)-based colorimetric sensor, 36−38 paper-based device, 39 and FASTinov ultrarapid flow cytometry.…”

“…It usually takes 20–72 h to increase the bacterial concentration but the sensitivity is still relatively low. , Various rapid identification of bacteria and AST methods have been developed in recent years and are primarily categorized into two types according to their applications in AST: genotypic and phenotypic AST . Genotypic assays can identify bacteria as well as acquire results of AST by detecting resistance genes, bypassing the need for lengthy culture and incubation, such as coated-silicon hybridization-based biosensor, colorimetric nanodiagnostic platform, fluorescence biosensor, photoelectrochemical assay, solid-phase polymerase chain reaction (SP-PCR), and the new commercial tests such as BioFire FilmArray blood culture identification panel and T2Magnetic Resonance-based assay. , Nonetheless, genotypic AST has limitations, such as the inability to identify strains with unclear gene mutations, and the presence of antibiotic resistance genes is not always consistent with phenotypic AST. , Phenotypic-based AST can determine bacterial growth with exposure to antibiotics and provide more convincing AST results, such as digital PCR, , digital real-time loop-mediated isothermal amplification (dLAMP), optical microscopy, microfluidic chip, ,– electrochemical biosensor, , chemiluminescence sensor, Raman spectrometry, – gold nanoparticle (AuNP)-based colorimetric sensor, – paper-based device, and FASTinov ultrarapid flow cytometry . However, these methods require expensive equipment/reagents or specific algorithms or are inapplicable for identification of pathogen infection in aseptic body fluids without first culturing the microorganisms due to the lack of sensitivity.…”