Rapid detection of enterobacteriaceae producing extended spectrum beta-lactamases directly from positive blood cultures by matrix-assisted laser desorption ionization-time of flight mass spectrometry

Abstract

Bacteria that produce extended-spectrum β-lactamases (ESBLs) are an increasing healthcare problem and their rapid detection is a challenge that must be overcome in order to optimize antimicrobial treatment and patient care. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) has been used to determine resistance to β-lactams, including carbapenems in Enterobacteriaceae, but the methodology has not been fully validated as it remains time-consuming. We aimed to assess whether MALDI-TOF can be used to detect ESBL-producing Enterobacteriaceae from positive blood culture bottles in clinical practice. In the assay, 141 blood cultures were tested, 13 of them were real bacteraemias and 128 corresponded to blood culture bottles seeded with bacterial clinical isolates. Bacteraemias were analysed by MALDI-TOF after a positive growth result and the 128 remaining blood cultures 24 h after the bacterial seeding. β-lactamase activity was determined through the profile of peaks associated with the antibiotics cefotaxime and ceftazidime and its hydrolyzed forms. Clavulanic acid was added to rule out the presence of non-ESBL mechanisms. Overall data show a 99% (103 out of 104) sensitivity in detecting ESBL in positive blood cultures. Data were obtained in 90 min (maximum 150 min). The proposed methodology has a great impact on the early detection of ESBL-producing Enterobacteriaceae from positive blood cultures, being a rapid and efficient method and allowing early administration of an appropriate antibiotic therapy.

The Continuing Plague of Extended-spectrum β-lactamase–producing Enterobacteriaceae Infections

“…185 In an attempt to reduce DAAT, several approaches to hasten the diagnosis of ESBLs have been explored including the detection of bla ESBL genes by microarray 186 or by using MALDI-ToF to detect cefotaxime-hydrolyzing Gram negatives from positive blood cultures. 187 Unfortunately, these methods are both expensive and require significant amount of work and expertise. In addition, unlike other important resistance traits, such as methicillin resistance in S aureus that are conferred by a single molecular mechanism, cephalosporin resistance may be caused by a multitude of genetic mechanisms that are difficult to detect by a single test.…”

Rapid Detection of OXA-48-Producing Enterobacteriaceae by Matrix-Assisted Laser Desorption Ionization−Time of Flight Mass Spectrometry

“…MALDI-TOF MS analysis, calibration, and spectra processing (flexAnalysis software; Bruker Daltonics GmbH, Germany) were carried out as previously described by Oviaño et al (10). The ertapenem spectrum was interpreted according to Sparbier et al (6).…”

Proteome-based bacterial identification using matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS): A revolutionary shift in clinical diagnostic microbiology

“…More recently, MALDI-TOF MS-based rapid and highly sensitive method was developed for detection of enterobacteriaceae producing extended spectrum beta-lactamases directly from positive blood cultures [82].…”