Rapid detection of cfiA metallo-β-lactamase-producing Bacteroides fragilis by the combination of MALDI-TOF MS and CarbaNP

摘要: Aims Carbapenem resistance in Bacteroides fragilis is emerging and mainly attributed to insertion sequence (IS)-mediated activation of the carbapenemase gene cfiA . We investigated use matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) CarbaNP assay for rapid identification these strains. Methods This study used Bruker MALDI Biotype system spectra models generated by 20 B. reference strains (10 -positive 10 -negative) ClinProTools software identify 404 (71 333 clinical isolates. The ability detect IS-mediated was assessed results obtained molecular analysis were as methods. Results support vector machine model found be most reliable algorithm differentiation -negative subgroups. Using direct transfer method, all but one isolates correctly identified two subgroups model. correct isolate upon retesting extraction method. Of 81 isolates, PCR sequencing showed that 30 had an IS element providing promoter With regard presence element, test upstream region 100% sensitivity, 80.4% specificity, 75.0% positive predictive value negative value. Conclusions combination MALDI-TOF MS can applied diagnostic laboratory with element-activated gene.