Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the detection of extended spectrum β-lactamases and carbapenemases among Gram-negative bacilli

Abstract

In the last few years, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has become the new gold standard method for the identification of microorganisms. Nevertheless, other useful applications of mass spectrometry have recently been demonstrated including the detection of resistance mechanisms. The MALDI-TOF-MS hydrolysis assay allows rapid detection of β-lactamase activity with results available within a few hours. Rapid detection of β-lactamases is important since β-lactam antibiotics remains as the mainstay of the treatment of several community-acquired and nosocomial infections, and a steady increase has been observed of resistant microorganisms associated with the production of extended spectrum β-lactamases (ESBLs) and carbapenemases. Several studies have reported the high sensitivity and specificity of the MALDI-TOF-MS antibiotic hydrolysis assay for the detection of ESBLs - or carbapenemase-producing Gram-negative bacilli. In addition, this technique can be performed directly from positive blood culture, significantly shortening the time of resistance detection. However, the standardization of assay conditions as well as automatic analysis of the spectra obtained is required. The aim of this review was to summarize the currently available data regarding the accuracy of the detection of β-lactamase activity using the MALDI-TOF-MS antibiotic hydrolysis assay.