细菌生物膜的电镜下特征及其与慢性鼻-鼻窦炎的关系

目的 观察慢性鼻-鼻窦炎(chronic rhinosinusitis,CRS)患者鼻内镜下所取钩突、筛窦黏膜标本是否存在细菌生物膜(bacterial biofilms,BF)及其形态学特征,探讨细菌生物膜在CRS发病机制中的作用.方法 对15例CRS伴有鼻息肉患者(试验组)和11例无CRS的鼻骨骨折患者(对照组),在鼻内镜下取钩突、筛窦黏膜(患者均知情同意),扫描电镜电镜下观察,判断标本中是否存在细菌生物膜,并描述其形态学特征.分析试验组与对照组之间的差异,对细菌生物膜的存在与部分临床指标进行相关分析.所有患者均行鼻窦CT检查并行CT评分.计量资料实验数据采用t检验,计数资料采用卡方检验,小样本计数资料用Fisher精确检验.结果 试验组15例患者中发现9例有细菌生物膜;对照组11例患者中发现1例有细菌生物膜,两者比较差异有统计学意义(χ~2=6.949,P<0.01).扫描电镜下,试验组9例患者标本中发现具有水通道、三维结构、基质包被的球形和椭圆形小体等典型特征的细菌生物膜.5例(包括1例对照组)标本发现除具有典型细菌生物膜特征外,还可见到与普通炎症导致的纤毛排列紊乱、缺失不同的纤毛黏聚.试验组细菌生物膜阳性患者的鼻窦CT评分(15.89±6.30)高于细菌生物膜阴性的患者(9.50±5.79),两者比较差异有统计学意义(t=2.14,P<0.05).结论 扫描电镜下可观察到CRS患者鼻黏膜中存在水通道、三维结构、基质包被的球形和椭圓形小体的典型形态特征的细菌生物膜.纤毛黏聚可能是细菌生物膜形成过程中的一种特有表现,是否也可以作为判断细菌生物膜存在的标志,有待于今后进一步研究.细菌生物膜的存在与CRS的发病密切相关,与疾病的严重程度相关,也可能是CRS难治的原因之一.

Relationship between bacterial biofilms and chronic rhinosinusitis by scanning electron microscopic study

Objective To determine the presence and the morphological features of bacterial biofilms in surgical specimens of patients with chronic rhinosinusitis (CRS) compared with control patients without CRS by scanning electron microscopy (SEM), and to evaluate the role of biofilm on the pathogenisis of CRS. Methods Fifteen patients with CRS undergoing endoscopic sinus surgery and 11 control patients with fracture of nasal bone were enrolled in this study. Clinical information was recorded from each patient. All patients underwent a thorough otolaryngological examination, preoperative paranasal sinus computerized tomography (CT) scanning which were evaluated according to the Lund-Mckay CT scoring system. All the samples including ancinate process, ethmoid mucosa from CRS group and uncinate process, ethmoid bulls from control group were prepared using standard methods for SEM. The presence of bacterial biofilms on the samples of two groups was observed by SEM. Statistical analysis was performed using SPSS 13.0. Continuous data was analyzed by Student t test and dichotomous data was analyzed by χ~2 or Fisher exact test. P was considered to be significant at a level of 0.05. Results Nine (60.0% )of the 15 patients were found to have evidence of biofilms. In control group, only 1 (9.1%) of 11 patients had biofilm. The difference was statistical significant(χ~2=6.949 ,P<0. 01 ). All controls except one had healthy appearing cilia and goblet cells without biofilms. All the 16 CRS patients showed aberrant findings of the mueosal surface with variation in degrees of severity from disarrayed cilia to complete absence of cilia and goblet cells. Among them the typical morphologic feature such as water channels, 3-D structure, and matrix-embedding spherical or elliptical bodies were noted in 9 cases. Five samples including one case from control showed cilia aggregation. The preoperative CT scores of the CRS patients with biofilms (n=9) were significantly higher than those without biofilms (n=6,t=2.14,P<0.05 ). Conclusions The typical morphologic feature of BF such as water channels, 3-D structure, and matrix-embedding spherical or elliptical bodies were noted in sinus mucosa of patients with CRS by the SEM. The positive rate of bacterial biofilms in CRS group was significantly higher compared to control group, which indicated bacterial biofilms might play an important role in the pathogenesis of CRS. Besides the typical bacterial biofilm features, cilia aggregation was found in five cases of CRS patients. We consider cilia aggregation can be regarded as one morphologic feature of bacterial biofilm in nasal mueosa, which needs further study. The presence of bacterial biofilms in CRS patients is associated with paranasal CT scores, which indicates that bacterial biofilm is correlated with the severity of CRS.