Identification of m/z characteristics of Staphylococcus aureus in agr and sigB regulatory system using MALDI-TOF-MS / 中华检验医学杂志

ABSTRACT

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 A total of 50 strains of Staphylococcus aureus were divided into two groups acute infection and chronic 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 SAS 030, 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 .