Sepsis is, despite the advances in antimicrobial therapy and supportive treatment, associated with high morbidity and mortality. Early identification of the causative agents of sepsis and their susceptibility to antibiotics is therefore crucial. In the master's thesis, we compared three new molecular methods for identifying bacteria directly from positive blood cultures. We compared saponin method and the Sepsityper kit (Bruker), which are two methods of preparing the sample for analysis with MALDI-TOF mass spectrometry and nested multiplex PCR FilmArray (BioFire Diagnostics, USA). All three methods were compared with standard routine methods of cultivation, identification and susceptibility testing for antibiotics. We tested 50 positive blood cultures (42 monomicrobial and 8 polymicrobial) with 61 isolates. We compared the methods according to the correctness of the identification and duration. FilmArray method gave the highest number of identifications in monomicrobial samples (95,2 %) but sometimes only to the higher taxonomic levels. The majority (88,1 %) of identifications to the species level in monomicrobial samples were obtained with Sepsityper kit and 66,7 % with saponin method. All methods gave best results in Gram-negative bacteria. When identifying bacteria from the polymicrobial samples FilmArray was the most succesful (73,7 %), being the only one capable of simultaneously identifying several microorganisms. With the FilmArray method, we also received data on the presence of determinants for resistance to antibiotics mecA, vanA/B and blaKPC. Saponin method was the fastest, with the average time of 14,4 minutes, compared to Sepsityper (41,9 min) and FilmArray (68,6 min).
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