Rapid method for direct identification of bacteria in urine and blood culture samples by matrix-assisted laser desorption ionization time-of-flight mass spectrometry: intact cell vs. extraction method

• Published in: Clinical microbiology and infection Vol. 17; no. 7; pp. 1007 - 1012
• Main Authors: Ferreira, L., Sánchez-Juanes, F., Muñoz-Bellido, J.L., González-Buitrago, J.M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Elsevier Ltd 01-07-2011; Blackwell Publishing Ltd; Wiley-Blackwell; Elsevier Limited
• Subjects: Bacteria - chemistry; Bacteria - classification; Bacteria - isolation & purification; Bacterial Infections - diagnosis; Bacteriological Techniques - methods; Biological and medical sciences; Blood - microbiology; Blood culture; clinical microbiology; Humans; identification; Infectious diseases; Lasers; MALDI-TOF MS; MALDI‐TOF MS; Mass spectroscopy; Medical sciences; Microorganisms; proteomics; Specimen Handling - methods; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Urine; Urine - microbiology; MALDI-TOF MS; identification; Blood culture; clinical microbiology; urine; Urine; Microbiology; Urine culture; Identification; Matrix assisted laser desorption ionization; Infection; Microbiological investigation; Time of flight method; Bacteria; Mass spectrometry; Comparative study
• ISSN: 1198-743X; 1469-0691
• DOI: 10.1111/j.1469-0691.2010.03339.x

Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a fast and reliable technology for the identification of microorganisms with proteomics approaches. Here, we compare an intact cell method and a protein extraction method before application on the MALDI plate for the direct identification of microorganisms in both urine and blood culture samples from clinical microbiology laboratories. The results show that the intact cell method provides excellent results for urine and is a good initial method for blood cultures. The extraction method complements the intact cell method, improving microorganism identification from blood culture. Thus, we consider that MALDI-TOF MS performed directly on urine and blood culture samples, with the protocols that we propose, is a suitable technique for microorganism identification, as compared with the routine methods used in the clinical microbiology laboratory.