title: MALDI-TOF mass spectrometry-based identification of group A Streptococcus isolated from areas of the 2011 scarlet fever outbreak in china.
abstract: There was a dramatic increase in scarlet fever cases in China from March to July 2011. Group A Streptococcus (GAS) is the only pathogen known to cause scarlet fever. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) coupled to Biotyper system was used for GAS identification in 2011. A local reference database (LRD) was constructed, evaluated and used to identify GAS isolates. The 75 GAS strains used to evaluate the LRD were all identified correctly. Of the 157 suspected β-hemolytic strains isolated from 298 throat swab samples, 127 (100%) and 120 (94.5%) of the isolates were identified as GAS by the MALDI-TOF MS system and the conventional bacitracin sensitivity test method, respectively. All 202 (100%) isolates were identified at the species level by searching the LRD, while 182 (90.1%) were identified by searching the original reference database (ORD). There were statistically significant differences with a high degree of credibility at species level (χ(2)=6.052, P<0.05 between the LRD and ORD). The test turnaround time was shortened 36-48h, and the cost of each sample is one-tenth of the cost of conventional methods. Establishing a domestic database is the most effective way to improve the identification efficiency using a MALDI-TOF MS system. MALDI-TOF MS is a viable alternative to conventional methods and may aid in the diagnosis and surveillance of GAS.
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 102206 Beijing, China.
authors.forename: Di
authors.initials: D
authors.lastname: Xiao
authors.forename: Yuanhai
authors.initials: Y
authors.lastname: You
authors.forename: Zhenwang
authors.initials: Z
authors.lastname: Bi
authors.forename: Haibin
authors.initials: H
authors.lastname: Wang
authors.forename: Yongchan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Bin
authors.initials: B
authors.lastname: Hu
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Song
authors.forename: Huifang
authors.initials: H
authors.lastname: Zhang
authors.forename: Zengqiang
authors.initials: Z
authors.lastname: Kou
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Yan
authors.forename: Menghan
authors.initials: M
authors.lastname: Zhang
authors.forename: Lianmei
authors.initials: L
authors.lastname: Jin
authors.forename: Xihong
authors.initials: X
authors.lastname: Jiang
authors.forename: Peng
authors.initials: P
authors.lastname: Su
authors.forename: Zhenqiang
authors.initials: Z
authors.lastname: Bi
authors.forename: Fengji
authors.initials: F
authors.lastname: Luo
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Zhang
mesh_terms: D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D016208:Databases, Factual; D004196:Disease Outbreaks; D006801:Humans; D012541:Scarlet Fever / Q000453:epidemiology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D013297:Streptococcus pyogenes / Q000145:classification* / Q000302:isolation & purification