HARNESSING MALDI-TOF AND PROTEOMICS TO RAPID ANTIMICROBIAL RESISTANCE DETECTION

Tailoring rapid and accurate antibiotic treatment to severely ill sepsis patients is crucial for their favorable outcome. For that aim, the microbiology laboratory should deliver prompt identification of the causative organism along with its antibiotic sensitivity profile. In the last few years, mass-spectrometry represented by the MALDI-TOF technology was introduced to the clinical microbiology laboratory. This technology has revolutionized the identification of bacteria and fungi shortening it to minutes and is now the most prominent tool for identification in clinical laboratories. Furthermore, this simple and accurate technology may also be used for rapid antimicrobial sensitivity testing (AST), shortening the results from 18-24 hours to 2-3 hours, allowing for same-day antibiograms. Two approaches of MALDI-TOF utilization for AST currently exist: 1. indirect detection of antibiotic degrading enzymes. 2. Phenotypic-like approach in which the metabolic rate of bacteria is estimated in the presence of various antibiotics. The latter (MBT-ASTRA) was applied in Emek Medical Center on bacteria taken directly from positive blood culture bottles of septic patients. Within 150 minutes from incubation we received antibiograms of pathogens from 68 patients with excellent correlation to minimal inhibitory concentration (MIC) obtained by conventional agar-based method (E-test) over-night. Further studies are conducted to correlate the MALDI-TOF assays with the actual MIC methods. In the era of increasing antimicrobial resistance, the precise yet cautious use of antibiotics is mandatory. Thus MALDI-TOF technology not only allows for rapid identification but may also guide the antibiotic treatment improving both patient outcome and antibiotic stewardship.