尿路感染症分離菌の膀胱定着に関する研究  [in Japanese] ADHESIVE PROPERTIES OF BACTERIA ISOLATED FROM PATIENTS WITH URINARY TRACT INFECTION TO THE URINARY BLADDER  [in Japanese]

(背景と目的)臨床分離株であるStaphylococcus epidermidis KK3-75株,Enterococcus faecalis SMU-14株,Escherichia coli TF6-27株を用い,膀胱定着性の違いを検討した。(対象と方法)マウス実験的膀胱炎は,各菌液を経尿道的に接種して作製し,病理組織像を光学顕微鏡,共焦点レーザー顕微鏡および電子顕微鏡にて観察した。また,菌体画分とマウス膀胱粘膜画分ならびに細胞外マトリックスの相互の結合性は Western blottingにより検討した。(結果)実験的膀胱炎組織での炎症反応の程度は,Enterococcus faecalis SMU-14株の場合では他の2菌株の場合に比べて弱かった。Staphylococcus epidermidis KK3-75株,Escherichia coli TF6-27株には厚い莢模様構造が観察された。菌体のマウス膀胱組織における分布は,各菌株で異なり,それぞれの菌体画分と細胞外マトリックスとの結合性の違いに相関した。すなわち,I型コラーゲンにはEnterococcus faecalis SMU-14株,Escherichia coli TF6-27株,フィブロネクチン,IV型コラーゲンにはStaphylococcus epidermidis KK3-75株,Enterococcus faecalis SMU-14株が結合性を示した。菌体の表層画分と膀胱粘膜画分との結合様式は,各菌株により異なった。さらに各菌体表層画分の膀胱粘膜画分への結命には,細胞外マトリックスにて阻害されるものを認めた。(結論)これらの結果より,各菌株の膀胱組織への定着の差は,菌体表噌の成分と膀胱粘膜画分および細胞外マトリックスとの結合の違いに基づくことが示唆され,各菌株による尿路感染症の発症進展の違いに関与すると考えられる。

(Background) Clinically isolated Staphylococcus epidermis KK3-75, Enterococcus faecalis SMU-14, and Escherichia coli TF6-27 were subjected to test for bladder lodgments. (Methods) Experimental cystitis on mice was investigated pathologically by light, confocal laser, and electron microscope after intravesical injection of cell suspensions of the strains. Bacterial affinities with bladder mucosal proteins and with extracellular components were detected by Western blot analysis. (Results) Pathological findings of experimental cystitis revealed prominent infiltration of neutrophils except for those that were challenged with Enterococcus faecalis SMU-14. Capsulelike structures were demonstrated for the other two strains. Each strain showed histological tropism within the tissue sections, which correlated with the capability to bind the respective extracellular matrix components tested. Type I collagen bound only to cellular extracts of Enterococcus faecalis SMU-14 and Escherichia coli TF6-27, whereas fibronectin and type IV collagen bound only to those of Staphylococcus epidermidi KK3-75 and Enterococcus faecalis SMU-14. Bladder mucosal proteins had a variety of ability to bind cell surface proteins of each strain. Bacterial cell surface binding of all except for two of the bladder mucosal proteins detected was inhibited by extracellular matrix components. (Conclusion) These experimental results suggest that the bacterial affinity of the bladder restricted by strain specific cell surface properties may be important for explanation in the difference of occurrence and progression of urinary tract infections caused by each strain.