Matajira Carlos E C, Moreno Luisa Z, Gomes Vasco T M, Silva Ana Paula S, Mesquita Renan E, Doto Daniela S, Calderaro Franco F, de Souza Fernando N, Christ Ana Paula G, Sato Maria Inês Z, Moreno Andrea M
School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil (Matajira, Moreno, Gomes, Silva, Mesquita, Doto, Calderaro, de Souza, Moreno).
Environmental Company of São Paulo State, São Paulo, Brazil (Christ, Sato).
J Vet Diagn Invest. 2017 Mar;29(2):245-249. doi: 10.1177/1040638716686641. Epub 2017 Jan 9.
Traditional microbiological methods enable genus-level identification of Streptococcus spp. isolates. However, as the species of this genus show broad phenotypic variation, species-level identification or even differentiation within the genus is difficult. Herein we report the evaluation of protein spectra cluster analysis for the identification of Streptococcus species associated with disease in swine by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A total of 250 S. suis-like isolates obtained from pigs with clinical signs of encephalitis, arthritis, pneumonia, metritis, and urinary or septicemic infection were studied. The isolates came from pigs in different Brazilian states from 2001 to 2014. The MALDI-TOF MS analysis identified 86% (215 of 250) as S. suis and 14% (35 of 250) as S. alactolyticus, S. dysgalactiae, S. gallinaceus, S. gallolyticus, S. gordonii, S. henryi, S. hyointestinalis, S. hyovaginalis, S. mitis, S. oralis, S. pluranimalium, and S. sanguinis. The MALDI-TOF MS identification was confirmed in 99.2% of the isolates by 16S rDNA sequencing, with MALDI-TOF MS misidentifying 2 S. pluranimalium as S. hyovaginalis. Isolates were also tested by a biochemical automated system that correctly identified all isolates of 8 of the 10 species in the database. Neither the isolates of the 3 species not in the database ( S. gallinaceus, S. henryi, and S. hyovaginalis) nor the isolates of 2 species that were in the database ( S. oralis and S. pluranimalium) could be identified. The topology of the protein spectra cluster analysis appears to sustain the species phylogenetic similarities, further supporting identification by MALDI-TOF MS examination as a rapid and accurate alternative to 16S rDNA sequencing.
传统微生物学方法能够对链球菌属分离株进行属水平的鉴定。然而，由于该属的物种表现出广泛的表型变异，因此在属内进行种水平的鉴定甚至区分都很困难。在此，我们报告了通过基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）对与猪疾病相关的链球菌进行蛋白质谱聚类分析的评估。共研究了250株从患有脑炎、关节炎、肺炎、子宫炎以及泌尿或败血症感染临床症状的猪身上分离得到的类猪链球菌分离株。这些分离株来自2001年至2014年巴西不同州的猪。MALDI-TOF MS分析鉴定出86%（250株中的215株）为猪链球菌，14%（250株中的35株）为不解乳糖链球菌、停乳链球菌、鸡链球菌、解脲链球菌、戈登链球菌、亨利链球菌、猪肠道链球菌、猪阴道链球菌、缓症链球菌、口腔链球菌、多动物源链球菌和血链球菌。通过16S rDNA测序在99.2%的分离株中证实了MALDI-TOF MS的鉴定结果，其中MALDI-TOF MS将2株多动物源链球菌误鉴定为猪阴道链球菌。分离株还通过生化自动化系统进行了检测，该系统正确鉴定了数据库中10个物种中的8个物种的所有分离株。数据库中未包含的3个物种（鸡链球菌、亨利链球菌和猪阴道链球菌）的分离株以及数据库中包含的2个物种（口腔链球菌和多动物源链球菌）的分离株均无法被鉴定。蛋白质谱聚类分析的拓扑结构似乎支持物种的系统发育相似性，进一步支持将MALDI-TOF MS检测作为一种快速准确的替代16S rDNA测序的鉴定方法。
