scholarly journals Instant screening and verification of carbapenemase activity in Bacteroides fragilis in positive blood culture, using matrix-assisted laser desorption ionization–time of flight mass spectrometry

2014 ◽  
Vol 63 (8) ◽  
pp. 1105-1110 ◽  
Author(s):  
Åsa Johansson ◽  
Elisabeth Nagy ◽  
József Sóki
Keyword(s):  
Mass Spectrometry ◽  
Blood Culture ◽  
Positive Blood Culture ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Desorption Ionization ◽  
Flight Mass Spectrometry ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

scholarly journals Direct Identification of 80 Percent of Bacteria from Blood Culture Bottles by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Using a 10-Minute Extraction Protocol

2018 ◽  
Vol 57 (2) ◽  
Author(s):  
Loïc Simon ◽  
Estelle Ughetto ◽  
Alice Gaudart ◽  
Nicolas Degand ◽  
Romain Lotte ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Blood Culture ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Desorption Ionization ◽  
Flight Mass Spectrometry ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACTMatrix-assisted laser desorption ionization–time of flight mass spectrometry is not widely used to identify bacteria directly from positive blood culture bottles (BCBs) because of overlong protocols. The objective of this work was to develop and evaluate a simple extraction protocol for reliable identification from BCBs. The 10-min protocol was applied over a 5-month period. Direct identifications on day 0 were compared with those obtained from colonies on day 1 [log(score) of ≥2]. We evaluated a range of seven log(score) thresholds on day 0 from 1.4 to 2.0 to find the lower confidence score that provides the higher percentage of direct identifications without loss of accuracy. With a log(score) threshold of ≥1.5 at day 0, our protocol allowed us to identify 80% of bacteria in 632 BCBs (96% ofEnterobacteriaceae, 95% ofStaphylococcus aureus, 92% of enterococci, and 62% of streptococci). At least one bacterial species of the mixture was identified in 77% of the polymicrobial samples. The rapidity and reliability of the protocol were factors in its adoption for routine use, allowing us to save up to 24 h in identifying 80% of the bacteria in the BCBs and, thus, to supply useful information to adapt antibiotic therapy when necessary. We currently provide reliable daily direct identifications of staphylococci, enterococci,Enterobacteriaceae,Pseudomonas aeruginosa,and beta-hemolytic streptococci.

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