De Brucker Katrijn, Tan Yulong, Vints Katlijn, De Cremer Kaat, Braem Annabel, Verstraeten Natalie, Michiels Jan, Vleugels Jef, Cammue Bruno P A, Thevissen Karin
Centre of Microbial and Plant Genetics, CMPG, KU Leuven, Leuven, Belgium.
Centre of Microbial and Plant Genetics, CMPG, KU Leuven, Leuven, Belgium Department of Plant Systems Biology, VIB, Ghent, Belgium.
Antimicrob Agents Chemother. 2015;59(6):3052-8. doi: 10.1128/AAC.04650-14. Epub 2015 Mar 9.
In the past, biofilm-related research has focused mainly on axenic biofilms. However, in nature, biofilms are often composed of multiple species, and the resulting polymicrobial interactions influence industrially and clinically relevant outcomes such as performance and drug resistance. In this study, we show that Escherichia coli does not affect Candida albicans tolerance to amphotericin or caspofungin in an E. coli/C. albicans biofilm. In contrast, ofloxacin tolerance of E. coli is significantly increased in a polymicrobial E. coli/C. albicans biofilm compared to its tolerance in an axenic E. coli biofilm. The increased ofloxacin tolerance of E. coli is mainly biofilm specific, as ofloxacin tolerance of E. coli is less pronounced in polymicrobial E. coli/C. albicans planktonic cultures. Moreover, we found that ofloxacin tolerance of E. coli decreased significantly when E. coli/C. albicans biofilms were treated with matrix-degrading enzymes such as the β-1,3-glucan-degrading enzyme lyticase. In line with a role for β-1,3-glucan in mediating ofloxacin tolerance of E. coli in a biofilm, we found that ofloxacin tolerance of E. coli increased even more in E. coli/C. albicans biofilms consisting of a high-β-1,3-glucan-producing C. albicans mutant. In addition, exogenous addition of laminarin, a polysaccharide composed mainly of poly-β-1,3-glucan, to an E. coli biofilm also resulted in increased ofloxacin tolerance. All these data indicate that β-1,3-glucan from C. albicans increases ofloxacin tolerance of E. coli in an E. coli/C. albicans biofilm.
过去，与生物膜相关的研究主要集中在无菌生物膜上。然而，在自然界中，生物膜通常由多种物种组成，由此产生的多微生物相互作用会影响工业和临床相关结果，如性能和耐药性。在本研究中，我们发现大肠杆菌在大肠杆菌/白色念珠菌生物膜中不会影响白色念珠菌对两性霉素或卡泊芬净的耐受性。相比之下，与在无菌大肠杆菌生物膜中的耐受性相比，在多微生物大肠杆菌/白色念珠菌生物膜中，大肠杆菌对氧氟沙星的耐受性显著增加。大肠杆菌对氧氟沙星耐受性的增加主要是生物膜特异性的，因为在多微生物大肠杆菌/白色念珠菌浮游培养物中，大肠杆菌对氧氟沙星的耐受性不太明显。此外，我们发现，当用基质降解酶（如β-1,3-葡聚糖降解酶溶菌酶）处理大肠杆菌/白色念珠菌生物膜时，大肠杆菌对氧氟沙星的耐受性显著降低。与β-1,3-葡聚糖在介导生物膜中大肠杆菌对氧氟沙星耐受性方面的作用一致，我们发现，在由高β-1,3-葡聚糖产生的白色念珠菌突变体组成的大肠杆菌/白色念珠菌生物膜中，大肠杆菌对氧氟沙星的耐受性增加得更多。此外，向大肠杆菌生物膜中额外添加主要由聚-β-1,3-葡聚糖组成的多糖海带多糖，也会导致氧氟沙星耐受性增加。所有这些数据表明，来自白色念珠菌的β-1,3-葡聚糖会增加大肠杆菌/白色念珠菌生物膜中大肠杆菌对氧氟沙星的耐受性。
