鲍曼不动杆菌质粒指纹图谱分析及质粒与其耐药性关系的研究

目的监测鲍曼不动杆菌的院内感染状况,探讨质粒与其耐药之间的关系.方法用琼脂纸片扩散法(K-B法)测定鲍曼不动杆菌对14种抗生素的敏感性.微量碱裂解法快速提取质粒DNA,通过琼脂糖凝胶电泳获得质粒指纹图谱.对单质粒菌株采用质粒消除试验研究其与耐药性之间的关系.结果抗生素敏感性测试结果表明,大多数菌株显示出多重耐药性.71株临床分离株中有43株检测到质粒,根据质粒图谱可分为8个型别.质粒消除试验显示32.0 kb的质粒消除后耐药性无明显变化,22.0 kb的质粒消除后,该菌对部分抗菌药物的耐药性丢失.结论亚胺培南、舒普深和头孢吡肟具有较高的抗菌活性,可作为鲍曼不动杆菌感染的治疗药物.质粒指纹技术仍可作为院内感染流行病学调查的一种重要手段,其结果表明该院鲍曼不动杆菌感染呈散发的流行态势.22.0 kg的质粒与该菌对氨苄西林、哌拉西林、庆大霉素、阿米卡星的耐药性有关.

Analysing plasmid-fingerprint profiles and relationship between plasmids and resistance in acinetobacter baumannii

Objective: This paper tries to monitor the nosocomial infection situation of Acinetobacter baumannii and study the relationship between the plasmids and the resistance of Acinetobacter baumannii isolates. Methods: Susceptibility of 14 different antimicrobial agents was determined by Kirby-Bauer disk agar diffusion method. We extracted the plasmids using alkali-splitting method and obtained the plasmid-fingerprint profiles of the different isolates by 0.8% agarose gel electrophoresis. Plasmid-remove experiment was used to study the relationship between the plasmids and the resistance of Acinetobacter baumannii isolates. Results: The susceptibility test showed a majority of clinical isolates were multiresistant strains. 43 of 71 clinical isolates were confirmed to carry one or more plasmids, and these isolates could be typed into 8 categories according to their different plasmid-fingerprint profiles. The result of plasmid-remove experiment suggested that 32.0 Kb plasmid was insignificant to the resistance of this organism, but removing 22.0 Kb plasmid could cause the resistance loss of some antibiotics in these species. Conclusions: The result of susceptibility test in vitro indicats imipenem, cefoperazone/sulbactam and cefepime have more activities than other antibiotics, so they can be used as the treatments against the infections caused by Acinetobacter baumannii. The method of plasmid-fingerprint profiles could be used as an important approach of epidemic investigation in nosocomial infections, and the result showed the epidemical tendency was sporadic during this period we studied. 22.0 Kb plasmid was associated with the resistance to ampicillin, piperacillin ,gentamicin, amikacin in Acinetobacter baumannii isolates.