Pérez-Sancho Marta, Vela Ana I, García-Seco Teresa, González Sergio, Domínguez Lucas, Fernández-Garayzábal Jose Francisco
Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, Madrid, Spain.
Campus de Excelencia Internacional (CEI) Moncloa, Universidad Politécnica de Madrid (UPM)-Universidad Complutense de Madrid (UCM), Madrid, Spain.
PLoS One. 2017 Jan 26;12(1):e0170784. doi: 10.1371/journal.pone.0170784. eCollection 2017.
The application of MALDI-TOF MS for identifying streptococcal isolates recovered from clinical specimens of diseased pigs was evaluated. For this proposal, the MALDI BDAL Database (Bruker Daltoniks, Germany) was supplemented with the main spectrum profiles (MSP) of the reference strains of S. porci, S. porcorum and S. plurextorum associated with pneumonia and septicemia. Although these three species showed similar MALDI profiles, several peaks were recognized that can be useful for their differentiation: S. porci (4113, 6133, 7975 and 8228 m/z Da), S. plurextorum (3979, 4078, 4665, 6164, 6491, 6812, 7959 and 9330 m/z Da) and S. porcorum (3385, 3954, 4190, 6772, 7908, and 8381 m/z Da). After adding these MSPs, an evaluation was conducted to determine the accuracy of MALDI-TOF MS for the identification of streptococci from diseased pigs using 74 field isolates. Isolates were identified as S. suis, S. porcinus, S. dysgalactiae, S. hyovaginalis, S. porcorum, S. alactolyticus, S. hyointestinalis and S. orisratti. This is the first time that the latter three species have been reported from clinical specimens of pigs. Overall, there was good concordance (95.9%) between the results obtained from MALDI-TOF MS identification (best hint) and those from genotyping. Our results demonstrate the good performance of MALDI-TOF MS (100% sensitivity and specificity) for identifying most of the species of streptococci that can frequently be isolated from diseased pigs. However, conflicting results were observed in the correct identification of some isolates of S. dysgalactiae and S. alactolyticus.
评估了基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）在鉴定从患病猪临床标本中分离出的链球菌菌株方面的应用。针对此提议，用与肺炎和败血症相关的猪链球菌、猪源链球菌和多杀性链球菌参考菌株的主要光谱图谱（MSP）对MALDI BDAL数据库（德国布鲁克道尔顿公司）进行了补充。尽管这三个菌种显示出相似的MALDI图谱，但仍识别出了几个可用于区分它们的峰：猪链球菌（4113、6133、7975和8228 m/z Da）、多杀性链球菌（3979、4078、4665、6164、6491、6812、7959和9330 m/z Da）和猪源链球菌（3385、3954、4190、6772、7908和8381 m/z Da）。添加这些MSP后，使用74株现场分离株对MALDI-TOF MS鉴定患病猪链球菌的准确性进行了评估。分离株被鉴定为猪链球菌、猪链球菌、停乳链球菌、阴道链球菌、猪源链球菌、无乳链球菌、肠道链球菌和鼠口腔链球菌。这是首次从猪的临床标本中报告后三个菌种。总体而言，MALDI-TOF MS鉴定（最佳提示）结果与基因分型结果之间具有良好的一致性（95.9%）。我们的结果表明，MALDI-TOF MS在鉴定大多数可从患病猪中频繁分离出的链球菌菌种方面具有良好性能（100%敏感性和特异性）。然而，在停乳链球菌和无乳链球菌一些分离株的正确鉴定中观察到了相互矛盾的结果。
