临床分离表皮葡萄球菌相关基因与生物膜表型的关系

目的：分析临床分离表皮葡萄球菌 icaA、aap 、atlE、sarA 基因与生物膜表型的关系。方法收集临床分离的表皮葡萄球菌78株，采用 PCR 法扩增 icaA、aap 、atlE、sarA 基因，组织细胞培养板黏附法检测生物膜表型，χ2检验分析上述基因与生物膜表型的关系，Wilcoxon 符号秩检验分别分析 icaA ＋菌及 icaA -菌在胰酶大豆肉汤（TSB）与TSB＋3％氯化钠中生物膜表型光密度（OD）值的差异。结果78株表皮葡萄球菌 icaA、aap 、atlE、sarA 基因阳性率分别为24．4％（19/78）、79．5％（62/78）、73．8％（57/78）、82．1％（64/78）。产生物膜株阳性率为51．3％（40/78），其中高产生物膜16株，均携带 icaA 基因；弱产生物膜24株。经统计学分析，上述基因与生物膜表型之间有相关性，icaA 基因与高产生物膜表型有相关性。icaA ＋菌及 icaA -菌在 TSB 与TSB＋3％氯化钠中生物膜 OD 值的差异有统计学意义（P ＜0．05）。结论表皮葡萄球菌生物膜表型涉及多种因子参与，而 icaA 基因有助于高产生物膜表型形成。环境因素也可影响表皮葡萄球菌生物膜表型。

Correlation bewteen associated genes and biofilm phenotype in Staphylococcus epidermidis

Objective To investigate the relationship of icaA,aap ,atlE,sarA gene with biofilm phenotype in Staphyloccus epidermidis .Methods Tissue culture plates assays were used to assess biofilm-forming ability of 78 Staphyloccus epidermidis strains.The presence of icaA,atlE,aap ,sarA gene was amplified with PCR method,the relationship between these genes and bio-film phenotype was evaluated by χ2 test and the difference of the biofilm OD′s value in TSB and TSB＋3% NaCl by icaA ＋ strains and icaA - strains was evaluated by Wilcoxon sign test,respectively.Results The positive rates of icaA,atlE,aap ,sarA gene were 24.4%（19/78）,79.5%（62/78）,73.8%（57/78）,82.1%（64/78）,respectively.40 biofilm-positive strains were detected（51.3%）, among which 16 strains carried icaA gene,24 strains showed weak biofilm-forming ability.Those genes above with biofilm formation were statistically correlated.Moreover,there was a relation between the icaA gene and the high biofilm-producing phenotype. There was a significant difference between the biofilm OD values in TSB and TSB＋3% NaCl by icaA ^＋ strains and icaA - strains, respectively.Conclusion Multiple genes are involved in Staphylococcus epidermidis biofilm-positive phenotype,but the icaA gene contributes to the high biofilm-forming phenotype.Biofilm phenotype is also influenced by environmental factors.