Rapid Identification Technology Of Invasive Filamentous Fungi Based On MALDI-TOF MS

Objective:To evaluate the application value of matrix-assisted laser desorption ionization-time of flight mass spectrometry(MALDI-TOF MS)technology in the identification of clinical common filamentous fungi in clinical practice.Methods:From April 2017 to February 2019,29 filamentous fungi were isolated and cultured from clinical specimens of various types in Hunan People's Hospital,First Affiliated Hospital of Hunan Normal University,and 26 common filamentous fungi donated by the Microbiology Laboratory of Laboratory Department of Peking Union Medical College Hospital.After the 55 filamentous fungi were identified by traditional morphological identification,DNA sequencing and MALDI-TOF MS,the results of DNA sequencing were compared with those of the other two methods to evaluate the application of MALDI-TOF MS in the identification of clinical filamentous fungi.Results:The filamentous fungi cultured at 28?and 35?were identified by mass spectrometer,the Chi-square test(?~2 test,P=0.05)showed that P>0.05,suggesting that there was no significant difference in culture temperature between the two groups.Using DNA sequencing results as gold standard,the correct identification rate of traditional morphological methods was 69.1%(38/55),while that of MALDI-TOF MS technology was 96.4%(53/55).In this study,the correct identification rate of filamentous fungi by mass spectrometry was 83.6%(46/55)after extracting protein by acetonitrile formate extraction method,while that of protein extracted by magnetic bead grinding method was 96.4%(53/55).Conclusion:In clinical routine work,when using mass spectrometer to identify filamentous fungi,the culture temperature will not affect the mass spectrometry identification results;the correctness of mass spectrometry after improved magnetic bead grinding method to extract protein is better than that recommended by mass spectrometer to extract acetonitrileformate;comparedwithtraditionalmorphological identification,MALDI-TOF MS technology is faster,more objective,more efficient and more accurate in identification of filamentous fungi.