Stevens Niall T, Greene Catherine M, O'Gara James P, Humphreys Hilary
Department of Clinical Microbiology, Royal College of Surgeons in Ireland Education & Research Centre, Beaumont Hospital, Dublin 9, Ireland.
Department of Medicine, Royal College of Surgeons in Ireland Education & Research Centre, Beaumont Hospital, Dublin 9, Ireland.
J Med Microbiol. 2009 Jul;58(Pt 7):855-862. doi: 10.1099/jmm.0.009209-0. Epub 2009 Jun 5.
Staphylococcus epidermidis biofilm causes device-related meningitis in neurosurgical patients. This study assessed the contribution of polysaccharide and protein to the development of a strong biofilm-positive phenotype in four S. epidermidis isolates associated with probable device-related meningitis, under varying environmental conditions. RT-PCR analysis of the intercellular adhesion operon (icaADBC) and assessment of polysaccharide intercellular adhesin (PIA) production indicated a correlation between increased icaA transcription and PIA production in ica(+) isolates grown in medium with 4 % ethanol and 4 % NaCl. Treatment of biofilm with sodium metaperiodate caused dispersion of adhered cells (P <0.0001), indicating involvement of PIA. Transcriptional levels of protein factors revealed that atlE transcription levels were similar in all isolates, whilst aap levels were variable, with induction being seen in two isolates following growth in the presence of alcohol or salt. Transcription of agr did not influence protein expression and RNAIII transcription varied among the strains. Although aap transcription was induced, the treatment of biofilm with proteinase K did not always disperse the biofilm. Our data suggest that, among the three ica(+) S. epidermidis isolates clinically associated with meningitis that were studied, PIA contributed to the strong biofilm-positive phenotype, whereas protein factors appeared to have a secondary role.
表皮葡萄球菌生物膜可导致神经外科患者发生与器械相关的脑膜炎。本研究评估了在不同环境条件下，多糖和蛋白质对4株与可能的器械相关脑膜炎相关的表皮葡萄球菌分离株中强生物膜阳性表型形成的作用。对细胞间黏附操纵子（icaADBC）进行逆转录聚合酶链反应（RT-PCR）分析以及评估多糖细胞间黏附素（PIA）的产生，结果表明，在含4%乙醇和4%氯化钠的培养基中生长的ica(+)分离株中，icaA转录增加与PIA产生之间存在相关性。用偏高碘酸钠处理生物膜导致黏附细胞分散（P<0.0001），表明PIA参与其中。蛋白质因子的转录水平显示，所有分离株中atlE的转录水平相似，而aap水平各不相同，在两种分离株中，在有酒精或盐存在的情况下生长后可观察到诱导现象。agr的转录不影响蛋白质表达，RNAIII转录在各菌株间有所不同。尽管aap转录被诱导，但用蛋白酶K处理生物膜并不总是能使生物膜分散。我们的数据表明，在所研究的3株临床上与脑膜炎相关的ica(+)表皮葡萄球菌分离株中，PIA促成了强生物膜阳性表型，而蛋白质因子似乎起次要作用。
