eDNA水平差异对表皮葡萄球菌临床株生物被膜形成能力的影响  

Influence of different extracellular DNA levels in Staphylococccus epidermidis isolates on the ability of biofilm formation

作　　者：王荔[1] 宋诗铎[1] 于树云[1] 

机构地区：[1]天津医科大学第二医院天津市感染性疾病研究所,300211

出　　处：《中华微生物学和免疫学杂志》2012年第1期1-5,共5页Chinese Journal of Microbiology and Immunology

摘　　要：目的检测表皮葡萄球菌（表葡菌）临床株生物被膜的形成能力，研究胞外DNA（eDNA）水平差异对表葡菌临床株生物被膜形成能力的影响。方法收集227株临床分离表葡菌，黏附试验检测其生物被膜的形成能力，PCR方法扩增icaA基因片段，黏附试验阳性和icaA基因扩增阳性的表葡菌为成膜组，黏附试验阴性和icaA基因扩增阴性的表葡菌为非成膜组，应用浮游培养法和微量板静置培养法检测eDNA水平，激光共聚焦显微镜（CLSM）观察生物被膜中eDNA的分布。结果227株表葡菌中黏附试验阳性26株，icaA基因阳性32株。选取黏附试验阳性和icaA基因扩增阳性的成膜组表葡菌20株，黏附试验阴性和icaA基因扩增阴性的非成膜组表葡菌19株，浮游培养2、4、6h后，成膜组菌株的eDNA水平分别为（32．2±10．1）μg／ml、（33．6±11．9）μg／ml、（34．3±10．0）μg／ml，非成膜组菌株的eDNA水平分别为（28．7±8．9）μg／ml、（31．5±11．7）μg／ml、（31．8±12．7）μg/ml，浮游培养成膜组菌株各时相eDNA水平分别高于非成膜组菌株，但差异尚无显著性（P〉0．05）。微量板静置培养法成膜组20株eDNA水平为（740．0±264．4）ng／A600，高于非成膜组19株eDNA水平（80．1±31．1）ng／A600两组之间比较差异具有显著性（P〈0．05）。通过AO-PI荧光染色于CLSM下观察静置培养的成膜株表葡菌Y36，其生物被膜中可见eDNA分布；非成膜株Y26没有生物被膜结构形成，未见eDNA分布。结论表葡菌临床株具有形成生物被膜的能力，eDNA是表葡菌形成生物被膜的重要基质成分，在判断表葡菌生物被膜形成能力方面微量板静置培养法检测eDNA水平优于浮游培养法。Objective To determine the ability of biofilm formation of Staphylococcus epidermidis isolates and study the influence of different extracellular DNA（eDNA） levels in S. epidermidis isolates on the ability of biofilm formation. Methods Detect the biofilm-formation ability of 227 S. epidermidis isolates with adhesion assays, amphfy the icaA gene fragment with PCR. The S. epidermidis isolates were divided into bio-film formation（BF） group and non-biofilm formation （NBF） group according to adhesion assays and icaA amplification. Detect eDNA levels of S. epidermidis in planktonic culture and microtitre plate static culture. The eDNA in S. epidermidis biofilms stained by AO-PI was observed by CLSM. Results 26 isolates were positive in adhesion assays and 32 isolates existed icaA gene among 227 S. epidermidis isolates. Select 20 iso-lates with positive adhesion assays and positive icaA amplification for BF group. Select 19 isolates with negative adhesion assays and negative icaA amplification for NBF group. The eDNA levels were （32.2±10.1）μg/ml, （33.6±11.9） μg/ml, （34.3±10.0） μg/ml in BF group when cultured in planktonic condition for 2, 4, 6 h, while the eDNA levels in NBF group were （28.7±8.9） μg/ml, （31.5±11.7） μg/ml, （31.8±12.7）μg/ml respectively. There were no significant differences between the two groups for these three phases（P〉0.05） , though the eDNA levels of BF group were higher than that of NBF group. The eDNA levels were （740.0±264.4） ng/A60o in BF group when cultured in static microtitre plate, higher than that of NBF group, （80.1±31.1） ng/A60o, and the difference between these two groups was significant. The eDNA in BF isolate Y36 biofilms could be visualized by staining with AO and PI when observed by CLSM, while neither biofilm structure nor eDNA appeard when NBF isolate Y26 was cultured for 24 h. Conclusion S. epi-dermidis isolates have the ability of biofilm formation, eDNA is one of the important matrix components in the S. epidermidis b

关 键 词：EDNA 表皮葡萄球菌 细菌生物被膜 微量板静置培养法 

分 类 号：R378[医药卫生—病原生物学]