Objective To study the application of serological tests and matrix-assisted laser desorption ionization time- of-flight mass spectrometry (MALDI-TOF-MS) in the detection of Salmonella typing and drug sensitivity tests, and we compare the drug resistance differences between Salmonella typhimurium and all other Salmonella for provision clinical purposes of medication.
Methods Totally 40 strains of non-repetitive Salmonella were isolated from fecal samples from children with diarrhea; BD phoenix M50 automatic bacterial identification drug sensitivity analysis system was used for bacterial identification and drug sensitivity test, followed by Salmonella serotyping; WHONET 5.6 software and SPSS13.0 software analyzed the bacterial resistance. The MALDI-TOF-MS method was used for mass spectrometry identification of Salmonella.
Results Forty strains were identified as Salmonella by instrument. Serological tests were divided into 10 serotypes and belong to 5 serogroups. The dominant serotype was Salmonella typhimurium, accounting for 65.0%; followed by Salmonella enteritidis and Salmonella stanley, each accounted for 7.5%, and no Salmonella typhi and Salmonella paratyphi were detected; the results of MALDI-TOF-MS identification could be identified to the species level, and the matching scores were> 2.300. When the difference level is 200, it can be divided into 20 types, of which 14 strains are single strains. Compared with the MALDI-TOF-MS identification results, the serological typing of 28 strains was consistent with the serotype, mainly Salmonella typhimurium, Salmonella enteritidis, and Salmonella stanley; 12 strains were not consistent with the serotype. Serological typing is closely related to the MALDI-TOF-MS method, but the two method do not correspond exactly. The results of Salmonella susceptibility test showed that the antibacterial drugs with higher drug resistance rate were ampicillin, piperacillin, and tetracycline, all greater than 70.0%; for amikacin, meropenem, piperacillin / tazobactam, ceftazidime and imipenem are sensitive.
Conclusions Both methods can quickly and accurately identify Salmonella, MALDI-TOF-MS method and serological typing, which is of great significance for the rapid identification and epidemiological study of Salmonella.
摘要： 目的 研究血清学试验和基质辅助激光解吸电离飞行时间质谱 (MALDI-TOF-MS) 在沙门菌分型检测中的 应用和药敏试验结果, 比较鼠伤寒沙门菌和其他所有沙门菌的耐药差异, 为临床用药提供依据。 方法 收集腹泻儿童 粪便标本中分离非重复沙门菌属 40 株; 采用 BD phoenix M50 全自动细菌鉴定药敏分析系统进行细菌鉴定和药敏试验, 再进行沙门菌血清型分型; 利用 WHONET 5.6 软件及 SPSS13.0 软件对细菌耐药性进行统计分析; 采用 MALDI-TOF-MS 法对沙门菌进行质谱鉴定。 结果 40 株经仪器鉴定为沙门菌株, 血清学试验分为 10 个血清型, 分属 5 个血清群, 优势 血清型为鼠伤寒沙门菌, 占 65.0%; 其次为肠炎沙门菌和斯坦利沙门菌, 各占 7.5%, 未检出伤寒和副伤寒沙门菌; MAL⁃ DI-TOF-MS 鉴定结果均能鉴定到种属水平, 且匹配分数均>2.300。当差异水平为 200 时, 可分为 20 个型别, 其中 14 株 为单株菌。血清学分型与 MALDI-TOF-MS 鉴定结果相比：28 株鉴定结果与血清型一致, 主要为鼠伤寒沙门菌、肠炎沙 门菌和斯坦利沙门菌; 12 株鉴定结果与血清型不一致。血清学分型与 MALDI-TOF-MS 法关系密切, 但两者不完全对 应。沙门菌药敏试验结果显示, 耐药率较高的抗菌药物依次为氨苄西林、哌拉西林、四环素, 耐药率均大于 70.0%; 对阿 米卡星、美洛培南、哌拉西林/他唑巴坦、头孢他啶、亚胺培南均敏感。 结论 两种方法均能快速准确鉴定出沙门菌, MALDI-TOF-MS 法和血清学分型配合使用, 对沙门菌的快速鉴定有重要意义。