Mechanisms of Ampicillin Resistance in Haemophilus influenzae Type B
Mechanisms of Ampicillin Resistance in Haemophilus influenzae Type B
复制标题
B型流感嗜血杆菌氨苄西林耐药机制
DOI：
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发表时间：
1976
影响因子：
4.9
通讯作者：
M. Patterson
中科院分区：
文献类型：
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作者：
R. Vega;H. Sadoff;M. Patterson
目的探讨B型流感嗜血杆菌氨苄西林耐药的遗传机制。在与体外总脱氧核糖核酸转移有关的实验中，野生型菌株的耐药性表达频率约为10%。氨苄西林对转化菌株的最低抑菌浓度与耐药供体菌株相似，转化子的耐药性与获得产生β-内酰胺酶的能力有关。吖啶39 μg/ml作用18 h，耐药率可达80%，部分菌株经反复传代后可自发丧失耐药性。氯化铯-溴化乙锭密度梯度离心法分析表明，耐药菌株中存在染色体外脱氧核糖核酸，进一步证明耐药因子是质粒介导的。
The genetic mechanisms associated with ampicillin resistance in strains of Haemophilus influenzae type b were investigated. In experiments concerned with transfer of total deoxyribonucleic acid in vitro, expression of resistance by wild-type strains occurred at a frequency of about 10%. The minimum inhibitory concentration of ampicillin for the transformed strains was similar to that of the resistant donor strains, and resistance in transformants was associated with acquisition of the ability to produce beta-lactamase. Exposure to 39 μg of acridine per ml for 18 h cured resistance at a frequency of 80%, and there was spontaneous loss of resistance after repeated subculture of some strains. Analysis by cesium chloride-ethidium bromide density gradient centrifugation demonstrated the presence of extrachromosomal deoxyribonucleic acid in the resistant strains, providing further evidence that the resistance factor is plasmid mediated.