金黄色葡萄球菌agr和sigB调控系统的MALDI-TOF质谱m／z特征分析

Identification of m/z characteristics of Staphylococcus aureus in agr and sigB regulatory system using MALDI-TOF-MS

目的通过分析金黄色葡萄球菌的质谱图m／z特征，评估菌体的agr和sigB调节系统的表达情况以及菌体在宿主体内的感染状态。方法回顾性分析，选取天津市第一中心医院2013年6月至2014年2月保藏的基因分型特征明确的金黄色葡萄球菌50株，通过VitekMS质谱的科研（RUO）模式获取菌株的质谱图，分析代表agr和sigB系统的m／z表达强度，应用SARAMIS软件构建基于质谱峰特征的系统发育树。结果50株金黄色葡萄球菌分为急性感染和慢性持续、复发感染两种类型，前者的delta毒素表达强度99．2±4．1，后者为60．5±10．1，t=16．83，P〈0．05；慢性持续、复发感染的sigB系统的调控增强，SAS030、SAS049和SA0772蛋白的表达强度分别为27．1±14．7、54．8±21．5和51．6±19．2，急性感染阶段相对应3种蛋白的表达强度分别是4．9±1．9、12．4±2．8和15．7±6．9，二者相比￡值分别为-6．88、-8．98和-1．87，P值均小于0．05。生物膜形成相关的酚溶调制肽（PSMs）表达强度不一，金黄色葡萄球菌小菌落变异型菌株的PSMα3相对强度为100％。结论通过agr和sigB调控系统的表达情况，可以评估金黄色葡萄球菌感染宿主的不同状态，MALDI—TOF质谱技术获取的m／z特征能够直观快捷地判断这一状态，该技术的深度应用有待进一步开发。

Objective The expression of agr and sigB regulation system in Staphylococcus aureus with different infection types were assessed by analyzing the characteristics of m/z value generated by MALDI-TOF-MS. Methods A total of 50 isolates with specific genotypes were collected from Tianjin First Center Hospital during Jun 2013 to Feb 2014 for retrospective study. The pattern profiles of these isolates were obtained by MALDI-TOF-MS with RUO model, and the m/z value was also analysed to evaluate the expression the agr and sigB regulation system. The phylogenetic tree based on mass spectrum peak feature was constructed using SARAMIS software. Results divided into two groups： acute infection and chronic A total of 50 strains of Staphylococcus aureus were persistent and recurrent infection. The expression of delta toxin in acute infection and in chronic infection was 99.2 ± 4. 1 and 60. 5 ± 10. 1 （ t = 16. 83, P 〈 0.05 ） , respectively. The regulation of stress proteins of sigB system was enhanced in chronic persistent and recurrent infections, and the expression intensities of SAS030, SAS049 and SA0772 were 27.1 ±14.7, 54.8± 21.5 and 51.6 ± 19.2, respectively; while in acute infections, those were 4.9 ±1.9, 12.4± 2.8 and 15.7± 6.9, respectively. The t values between the two groups were - 6.88 （ P 〈 0.05 ） , - 8.98 （ P 〈 0.05 ） and - 1.87 （ P 〈 0.05 ）, respecitively. The expression of phenol-soluble modulins （ PSMs ） was inconsistent, and the relative strength of PSMα3 was 100% in the colony variants small strains. Conclusions Different types of the Staphylococcus aureus infections could be evaluated through the assessment of the agr and sigB regulation system. The m/z value obtained by MALDI-TOF mass spectrometry is a marker for the expression of agr and sigB regulation system. The application of this technology needs further development.