土壤中一株抗生素和重金属交叉抗性菌的筛选及抗性研究

摘要

In order to explore the resistance influence of heavy metal Zn2 + to antibiotic-resistant bacteria in soil, a cephalosporin-resistant strain,designated C -1,was isolated from soil,its physiological and biochemical char-acteristics,identification of molecular biology,the growth curve of bacteria in different concentrations of Zn2 +and cross-resistance of antibiotics/Zn2 + were studied.The results showed that the strain C -1 belongs to Pseudo-monas;it has resistance to Zn2 +,though the growth of it was inhibited by Zn2 + in some degree;the susceptibili-ty testing found that this strain only sensitive to streptomycin and sulfathiazole,Zn2 + coexisted with streptomycin or sulfathiazole exhibited synergistic bactericidal effect to the strain;the C -1 has multiple drug resistance, meanwhile having cross resistance to gentamicin /Zn2 + and neomycin /Zn2 +;the minimum inhibitory concentra-tion of C -1 to Zn2 + reached 50 mg/L.%通过对土壤中分离得到的一株头孢霉素的抗生素抗性菌 C －1进行生理生化特性、分子生物学鉴定、不同 Zn2＋浓度下细菌的生长曲线及抗生素和 Zn2＋的交叉耐药性研究，探索重金属 Zn2＋对土壤抗生素抗性菌抗性的影响．结果表明：抗头孢霉素细菌 C －1为假单胞菌属（Pseudomonas），生长繁殖易受 Zn2＋抑制，同时对 Zn2＋有一定抗性．对7种抗生素进行药敏试验发现，菌株 C －1仅对链霉素和磺胺噻唑敏感，Zn2＋与链霉素或磺胺噻唑共存时表现出协同杀菌性；菌株 C －1具有多重耐药性，对庆大霉素和 Zn2＋、新霉素和 Zn2＋有交叉抗性；菌株 C －1生长的最低 Zn2＋抑菌浓度为50 mg／L．