Abstract:
Objective
To evaluate the capability of matrix-assisted laser desorption ionizationtime of flight mass spectrometry (MALDI-TOF MS) for clinical bacteria identification.
Methods
A total of 4511 isolates which contained 3727 strains of common bacteria, 784 strains of fungi and 32 strains of rare bacteria were isolated from patients in Suzhou Hospital Affiliated to Nanjing Medical University during September 2014 to January 2015 and cultured as usual. They were identified with the MALDI-TOF MS and Phoenix-100 sensitivity analysis. The results were compared for identification. Fungi were identified by MALDI-TOF MS and traditional manual methods.
Results
The detection rates of 3727 strains identified by MALDI-TOF MS and Phoenix-100 were 97.0 % and 98.6% respectively. Another 35 strains of mucinous Klebsiella pneumoniae and 42 strains of mucinous Pseudomonas aeruginosa can be properly identified by Phoenix-100 rather than MALDI-TOF MS. There were significant differences between the detection rates of two systems for Klebsiella and Pseudomonas spp. (χ2=36.219, 17.288; P=0.000, respectively). For Morgan Escherichia, Achromobacter and Flavobacterium, both systems reached 100% detection rate. And no significant differences were found between the other spp. (Staphylococcus, Enterococcus, Escherichia, Enterobacter, Proteus, Acinetobacter spp., Burkholderia χ2 value of 2.304, 0.000, 0.000, 1.185, 1.343, 0.611,0.000; Serratia, Citrobacter spp., Providencia spp., Stenotrophomonas genus by Fisher test; P value of 0.05).For those 80 inconsistent results by two systems, 16S rRNA gene sequencing showed that MALDI-TOF MS correctly identified 47 strains, while Phoenix-100 only detected 28 strains successfully (χ2= 9.060, P= 0.003).With MALDI-TOF MS, the detection rates of Candida, Saccharomyces and Trichosporon were 90.7%, 100%and 100%, respectively, and 32 clinical rare bacteria (Bacillus, Lactobacillus, Trichosporon, Moraxella, Listeria monocytogenes and so on) got reliable results.
Conclusion
MALDI-TOF MS is a powerful method in routine rapid identification for pathogenic bacteria in clinical microbiology laboratories.
Key words:
Mass spectrometry,
Bacteria identification
Jingjing Gao, Yanan Wang, Qiao Zhong, Wenxiang Lu, Ying Zhou, Yuanjian Wu, Weidong Xu. Valuation of matrix-assisted laser desorption ionization-time of flight mass spectrometry for clinical bacteria identification capacity[J]. Chinese Journal of Clinical Laboratory Management(Electronic Edition), 2015, 03(01): 36-41.