产志贺毒素大肠杆菌O157∶H7的亚碲酸钾抗性基因簇分布和抗性水平  

Distribution of tellurite resistance gene cluster and its resistance level in Stx-positive E.coli O157∶H7

作　　者：李新军[1] 叶长芸[1] 张晶波[1] 卢珊[1] 白雪梅[1] 徐建国[1] 

机构地区：[1]中国疾病预防控制中心传染病预防控制所腹泻病研究室

出　　处：《中华微生物学和免疫学杂志》2003年第11期833-836,共4页Chinese Journal of Microbiology and Immunology

基　　金：国家自然科学基金资助项目 (3 0 0 70 0 42 )

摘　　要：目的　了解产志贺毒素大肠杆菌O15 7∶H7的亚碲酸盐抗性基因簇的分布和抗性水平的关系。方法　运用PCR和核酸杂交方法进行基因检测 ,使用平皿法检测亚碲酸钾抗性水平。结果在所检测的志贺菌、沙门菌、霍乱弧菌、耶尔森菌、泌尿道致病性大肠杆菌、肠产毒性大肠杆菌、肠致病性大肠杆菌、肠侵袭性大肠杆菌、肠黏附性大肠杆菌、肠出血性大肠杆菌中 ,只有大肠杆菌O15 7∶H7具有ter(telluriteresistance ,ter)基因簇。所检测的 34株产志贺毒素的大肠杆菌O15 7∶H7有 33株具有ter基因簇 ,所检测的 18株不产生志贺毒素的大肠杆菌O15 7,4株具有ter基因簇 ,但是没有该毒力岛的其它基因。ter基因阳性的 33株菌中 ,亚碲酸钾的抗性水平一般较高 ,4株在 75 0 μg ml以上 ,19株为5 0 0～ 75 0 μg ml,10株为 2 5 0～ 5 0 0 μg ml;而 4株ter基因簇阴性的菌株 ,也表现了高水平的耐药性 ,其抗性水平均为 5 0 0～ 75 0 μg ml。其它ter基因簇阴性的菌株 ,2 0株耐药性为 5～ 10 μg ml,1株 10～ 2 0 μg ml,6株 2 0～ 5 0 μg ml,2株 5 0～ 10 0 μg ml,1株 10 0～ 2 5 0 μg ml。结论　ter基因簇在产志贺毒素的大肠杆菌O15 7∶H7中高频率存在 ,而在其它病原菌中没有检测到。高水平的亚碲酸钾抗性可以作为选择性分离产志贺?Objective To investigate the presence of tellurite resistance (ter) gene cluster and its resistance in Shiga toxin producing Escherichia coli O157∶H7. Methods The ter gene cluster was tested by PCR and dot-blot hybridization. Tellurite resistance was evaluated by plate dilution method. Results The ter gene cluster is present in E.coli O157∶H7. In the enteric pathogens tested in this study, only isolates of E.coli O157∶H7 was identified to have ter gene cluster. However, it was only identified in 4 of 18 strains of Stx-negative E.coli O157, for which no other virulence gene of the UTA island was found. In 72 strains of enteric pathogens tested, the strains with ter gene cluster are usually resistant to high level of potassium tellurite. In contrast, the strains without ter gene cluster are sensitive to potassium tellurite. However, 4 ter-negative strains were resistant to 500μg/ml. Conclusion The ter gene cluster and potassium tellurite resistance were identified in 33 of 34 isolates of Stx-positive E.coli O157∶H7, but was not frequently identified in other enteric pathogens. This observation suggested that tellurite resistance can be considered as a selective marker for isolation of Stx-positive E.coli O157∶H7.

关 键 词：产志贺毒素大肠杆菌 O157:H7 亚碲酸钾抗性 基因簇 分布 抗性水平 

分 类 号：R378[医药卫生—病原生物学]