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目的了解长期抗菌药物压力及常用紫外线消毒对鲍曼不动杆菌耐药性的影响及替加环素(TGC)耐药鲍曼不动杆菌耐药性在群体中存续的能力。方法选取临床分离TGC敏感鲍曼不动杆菌3株,分别采用多步法及紫外线照射体外诱导耐药,微量肉汤稀释法检测诱导前后鲍曼不动杆菌对TGC的最低抑菌浓度(MIC)变化。选取临床分离TGC耐药鲍曼不动杆菌2株,在空白MHA平板中反复传代,测定其MIC值。最后选取TGC敏感株及TGC诱导同源耐药株进行TGC耐药株适应度代价研究。结果应用多步法成功诱导出TGC耐药株;紫外线照射虽然对TGC耐药性未发生影响,但其MIC值有上升趋势。TGC耐药鲍曼不动杆菌传代40代后菌株MIC值无明显变化。TGC敏感株及TGC诱导同源耐药株进行相同条件下培养,体外单独培养时耐药株达到对数生长期及平台期的时间均较敏感株长;混合培养时,随着连续传代,耐药株菌落数量较敏感株迅速减少,甚至耐药株被清除。结论 TGC可诱导鲍曼不动杆菌产生获得性耐药。鲍曼不动杆菌对TGC的耐药可能具有遗传稳定性。TGC耐药株较敏感株适应性下降。
Objective To investigate the effect of long-term antibacterial drug pressure and commonly used ultraviolet disinfection on Acinetobacter baumannii resistance and the ability of TGC resistant Acinetobacter baumannii to survive in the population. Methods Three isolates of TGC-sensitive Acinetobacter baumannii were isolated from clinical isolates. Multi-step method and ultraviolet irradiation were used to induce drug resistance in vitro. The minimum inhibitory concentration (MIC) of Acinetobacter baumannii to TGC before and after induction was determined by micro broth dilution method. Variety. Two clinically isolated TGC-resistant Acinetobacter baumannii strains were selected and repeatedly passaged in blank MHA plates to determine their MIC values. Finally, TGC-sensitive strains and TGC-induced homologous drug-resistant strains were selected to study the fitness of TGC-resistant strains. Results The multi-step method was used to induce the TGC-resistant strains. Although the UV-radiation did not affect the drug resistance of TGC, its MIC value increased. After 40 passages of TGC resistant Acinetobacter baumannii strains, there was no significant change in MIC value. TGC sensitive strains and TGC induced homologous drug-resistant strains were cultured under the same conditions, when cultured alone in vitro resistant strains reached logarithmic growth phase and plateau period are more sensitive strain length; mixed culture, with continuous passage, resistance The number of drug-susceptible colonies decreased rapidly and even drug-resistant strains were eliminated. Conclusions TGC can induce acquired drug resistance of Acinetobacter baumannii. Acinetobacter baumannii TGC resistance may be genetic stability. TGC resistant strains more susceptible strains decreased.