气管导管生物被膜电镜观察及其与呼吸机相关性肺炎的 …

目的　观察气管导管内表面细菌生物被膜 (BF)形成情况并初步探讨其在呼吸机相关性肺炎 (VAP)发生中的作用。方法　用扫描电子显微镜和透射电子显微镜分别观察拔出的气管导管内表面 ,同时作下呼吸道和导管内壁细菌学检测。结果　 76 % (19/ 2 5 )气管导管内壁覆盖不定型基质物 ,其平均插管时间 (10 7± 7 9)天 ],长于无不定型基质物覆盖的导管的插管时间 (2 1± 0 8)天 ](P <0 0 5 ) ;78% (14/ 18)不定型基质物中含大量球菌或杆菌 ;导管内壁含致病菌的 16例中 ,11例在插管期间即从下呼吸道分泌物中分离得到相同菌株 ;在 7/ 8VAP患者中 ,VAP病原体与导管内分离的病原体相同。结论　气管导管内细菌BF形成与插管时间密切相关 ,导管内细菌BF的存在可能与VAP病原体有一定相关性。

Observation of biofilms inside tracheal tubes by electron microscopy and the relationship between biofilms and VAP

OBJECTIVE: To observe the formation of biofilms inside tracheal tubes and to evaluate the effect of biofilm on the development of ventilator associated pneumonia (VAP). METHODS: Biofilms inside tracheal tubes from intubated patients were observed by scanning electron microscopy and transmission electron microscopy, meanwhile bacteria were detected in the specimens from the lower respiratory tract and the inside of tracheal tubes. RESULTS: 76% (19/25) of inner surface of tracheal tubes was coated with a confluent amorphous matrix by scanning electron microscopy. The average duration of trach-intubation in this group (10.7 +/- 7.9) days] was longer than that in the other group (2.1 +/- 0.8) days] in which tracheal tubes were not coated with the confluent amorphous matrix (P < 0.05). The presence of many bacteria(14/18) within these amorphous matrix was confirmed by transmission electron microscopy. Of the sixteen tracheal tubes, eleven tubes grew the same organisms that had been isolated from the secretions of the lower respiratory tract before extubation. In some VAP patients (7/8), organisms isolated from tracheal tubes were the same organisms which were pathogenic organisms of VAP. CONCLUSIONS: There was a close connection between the formation of bacterial BF and the long-term indwelling tracheal tubes. The presence of bacterial BF in the inner of tracheal tubes might be associated with the pathogenic organisms of VAP.