Rapid detection of carbapenemase-producing Klebsiella pneumoniae strains derived from blood cultures by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS)

Abstract

BackgroundCarbapenemase-producing Enterobacteriaceae (CPE), particularly carbapenemase-producing Klebsiella pneumoniae isolates, are important causative agents of nosocomial infections associated with significant mortality rates mostly in critical wards. The rapid detection and typing of these strains is critical either for surveillance purposes and to prevent outbreaks and optimize antibiotic therapy. In this study, the MALDI-TOF MS method was used to detect rapidly these isolates from blood cultures (BCs) and to obtain proteomic profiles enable to discriminate between carbapenemase-producing and non-carbapenemase-producing strains.ResultsFifty-five K. pneumoniae strains were tested. Identification and carbapenemase-production detection assay using Ertapenem were performed both from bacterial pellets extracted directly from BCs flasks and from subcultures of these strains. For all isolates, a complete antimicrobial susceptibility testing and a genotypic characterization were performed.We found 100% agreement between the carbapenemase-producing profile generated by MALDI TOF MS and that obtained using conventional methods. The assay detected and discriminated different carbapenemase-producing K. pneumoniae isolates within 30 min to 3 h after incubation with Ertapenem.ConclusionsMALDI-TOF MS is a promising, rapid and economical method for the detection of carbapenemase-producing K. pneumoniae strains that could be successfully introduced into the routine diagnostic workflow of clinical microbiology laboratories.

Rapid detection of antibiotic resistance in positive blood cultures by MALDI-TOF MS and an automated and optimized MBT-ASTRA protocol forEscherichia coliandKlebsiella pneumoniae

“…With our optimized protocol, we demonstrate that an incubation time of 90 min can detect antibiotic resistance in E. coli and K. pneumoniae. Other findings suggest timeframes of 60 min to 4 h, depending on the bacteria species, chosen antibiotics, and its concentrations [18][19][20][21][22]31,32]. The antibiotic concentrations for the final analysis of the blood cultures were in our study set to 32 mg/l cefotaxime, 16 mg/l meropenem and 4 mg/l ciprofloxacin.…”

Typing and Species Identification of Clinical Klebsiella Isolates by Fourier Transform Infrared Spectroscopy and Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

“…With the increased availability of genome sequencing and proteomics technology, it seems desirable to identify more of these type-specific targets, which can be used in MALDI-TOF MS analyses. For example, in K. pneumoniae, the presence of an 11,109-Da mass peak was associated with carbapenemase-producing isolates (45)(46)(47). Our study included only one strain (four isolates) of K. quasipneumoniae, so further investigations with a larger set of strains are needed to determine if this species can also be reliably delineated by MALDI-TOF MS.…”

Semi-quantitative MALDI-TOF for antimicrobial susceptibility testing in Staphylococcus aureus

“…The application of MALDI-TOF MS for AST would provide further utility for this technique and allow rapid identification and susceptibility testing of pathogens with a single assay. Several ongoing efforts investigate methods for determining antimicrobial resistance via MALDI-TOF MS [ 7 , 8 ], including monitoring antibiotic modification by bacterial culture (e.g., β-lactam hydrolysis [ 9 , 10 ], acetylation of fluoroquinolones [ 11 ]), direct detection of proteins involved in specific resistance mechanisms [ 12 , 13 ], and detection of stable isotope labeling [ 14 , 15 ]. However, the former two methods rely on identification of a specific resistance mechanism and are only applicable with certain antibiotic classes, while the latter case requires expensive, isotopically labeled media.…”