engleski

New techniques in microbiology diagnostics – identifi cation of microorganisms in blood culture samples

ABSTRACT - In a clinical diagnostic microbiology laboratory, the identifi cation of bacterial or yeast isolates is currently mainly based on phenotypic characteristics. Th ese phenotypic analyses take several hours or an overnight period for full and optimal identifi cation and, in some cases, can be doubtful or imprecise in species identifi cation. Recent molecular methods, such as real-time PCR, sequence analysis or microarray analysis, have found some application in bacteriology. To optimize the care of patients with infectious diseases, there is still an urgent need for rapid and simple techniques for microbial identifi cation. Th e most promising techniques are proteomic technologies including matrix-assisted laser desorption-ionization time-of-fl ight mass spectrometry (MALDI-TOF MS). Novel applications of the systems in identifi cation of microbial species in clinical samples are also explored. Th is includes identifi cation of pathogens from positive blood cultures or directly from patients samples, such as urine. Currently, intriguing MALDI-TOF MS developments are made regarding the phenotypic detection of certain antibiotic resistance mechanisms, e.g. beta lactamases and carbapenemases. Several procedures have been described for the identifi cation of microorganisms contained in urine samples, enrichment broths or positive blood cultures. In comparison to traditional microbiological methods, MALDI-TOF MS can identify bacteria and yeast within minutes directly from the colonies grown on culture plates. Th is approach, which is radically new, tends to reduce costs of consumables and the length of diagnostic time. Th e reliability and accuracy of the method have been demonstrated in numerous studies and diff erent systems are already commercially available.

clinical microbiology; phenotypic identifi cation; matrix-assisted laser desorption-ionization

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