Department of Immunology and Infectious Biology, Institute of Microbiology, Biotechnology and Immunology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, 90-237, Lodz, Poland,
Arch Immunol Ther Exp (Warsz). 2013 Oct;61(5):413-20. doi: 10.1007/s00005-013-0240-3. Epub 2013 Aug 8.
Biofilms are probably one of the most common structures formed by microorganisms in various environments. The higher resistance of such microbial communities to stress conditions, including antibiotics and host immune response, is recently extensively studied. However, the weak activity of phagocytic cells against microbial biofilm is not yet fully understood and explained. The aim of this study was: (1) a qualitative and quantitative comparison of cell components/products released from Staphylococcus aureus biofilm or planktonic cultures, (2) evaluation of the influence of such cell components/products on murine leukocytes secretory function. For this, mouse peritoneal leukocytes were stimulated with biofilm or planktonic staphylococcal cultures or their acellular filtrates, and then the production of cytokines (TNF-α, IL-6, IL-10, MCP-1 and MIP-1α), hemolytic activity and staphylokinase (SAK) production was determined. It was found that similar staphylococcal components/products possessing the immunomodulatory properties, were present in both, biofilm and planktonic filtrates. Moreover, these compounds were similarly active in the stimulation of TNF-α and MCP-1 release from leukocytes. The hemolytic activity and SAK release by planktonic and biofilm cultures were also comparable. What is interesting, stronger stimulatory activity of biofilm-derived components/products of clinical S. aureus strains in the case of MIP-1α, IL-6 and IL-10 was noticed. On the other hand, taking into consideration the reference strains, MIP-1α production was enhanced by "planktonic filtrates". Thus, in our study it was proved, first of all, that biofilm is not a structure fully separated from the external environment. Second, the influence of these S. aureus constituents/metabolites on leukocytes seems to be more strain-dependent than culture phenotype-dependent. The lack of one common profile of biofilm and planktonic S. aureus cultures/filtrates biological activity indicates that the disturbances in cytokines' production could not be the only reason for the so-called "frustrated phagocytosis", connected with enhanced biofilm resistance.
生物膜可能是各种环境中微生物形成的最常见结构之一。最近，人们广泛研究了这种微生物群落对包括抗生素和宿主免疫反应在内的应激条件的更高抗性。然而，吞噬细胞对微生物生物膜的活性较弱的原因尚不完全清楚。本研究的目的是：（1）比较金黄色葡萄球菌生物膜或浮游培养物释放的细胞成分/产物的定性和定量；（2）评估这些细胞成分/产物对鼠白细胞分泌功能的影响。为此，用生物膜或浮游葡萄球菌培养物或它们的无细胞滤液刺激小鼠腹腔白细胞，然后测定细胞因子（TNF-α、IL-6、IL-10、MCP-1 和 MIP-1α）、溶血活性和葡萄球菌激酶（SAK）的产生。结果发现，具有免疫调节特性的类似葡萄球菌成分/产物存在于生物膜和浮游滤液中。此外，这些化合物在刺激白细胞释放 TNF-α和 MCP-1 方面具有相似的活性。浮游和生物膜培养物的溶血活性和 SAK 释放也相当。有趣的是，临床金黄色葡萄球菌菌株生物膜衍生成分/产物对 MIP-1α、IL-6 和 IL-10 的刺激活性更强。另一方面，考虑到参考菌株，“浮游滤液”增强了 MIP-1α 的产生。因此，在我们的研究中，首先证明了生物膜并不是与外部环境完全隔离的结构。其次，这些金黄色葡萄球菌成分/代谢物对白细胞的影响似乎更依赖于菌株，而不是培养表型。生物膜和浮游金黄色葡萄球菌培养物/滤液生物活性缺乏一个共同的特征表明，细胞因子产生的紊乱不可能是所谓的“受挫吞噬”的唯一原因，与增强的生物膜耐药性有关。
