磺胺氯哒嗪对大肠杆菌的生长、突变及接合转移效应的影响

Effects of sulfachloropyridazine on the growth,mutation and conjugation of Escherichia coli

抗生素的大量使用导致细菌的耐药性,直接威胁了人类的生命健康,加剧了抗生素的环境生态风险.为了研究抗生素抗性基因(antibiotic resistance genes,ARGs)的扩散与抗生素浓度之间的关系,本文以磺胺氯哒嗪(sulfachloropyridazine,SCP)为研究对象,测定了SCP对只有磺胺敏感大肠杆菌的单一菌液的生长和突变效应的影响,SCP对含有耐磺胺大肠杆菌和磺胺敏感大肠杆菌的混合菌液的生长、突变及RP4质粒和R388质粒的接合转移效应的影响.研究结果显示,单一菌液的突变促进效应浓度区间(RCS)和突变促进无效应浓度RC0-1皆小于混合菌液;4.0×10^(-5)—8.7×10^(-5)mol·L^(-1)浓度范围内SCP作用下,单一菌液的突变效应受抑制而混合菌液的突变效应相较于空白组显著促进(P<0.05);1.9×10^(-5)—6.3×10^(-5)mol·L^(-1)浓度范围的SCP能够促进混合菌液的突变,对ARGs的筛选风险较大,且SCP在6.3×10^(-5)—1.5×10^(-4)mol·L^(-1)范围对RP4和R388质粒的接合转移效应有明显的抑制作用,说明在本实验浓度范围内SCP对接合子的促进风险较小.综上,单一菌液的效应不足以说明环境中磺胺类抗生素的突变风险,研究磺胺类抗生素对耐药基因传播的影响时应混合耐磺胺大肠杆菌和磺胺敏感大肠杆菌作为受试菌,实验证明环境中低浓度的SCP对抗性基因的产生的促进风险较大.

The windespread use of antibiotics has lead to antibiotic resistance,which directlythreatens humans health and exacerbates and environmental ecological risk of antibiotics.In order to study the relationship between the concentration of antibiotics and the spread of antibiotic resistance genes（ARGs）,this work investigated the effects of sulfachloropyridazine（SCP） on the growth,mutation of single bacteria solution（sulfonamide-susceptible E.coli） and its effects on the growth,mutation and conjugation of mixed bacteria solution（sulfonamide-resistant E.coli sulfonamidesusceptible E.coli）.The results show that both the mutation promoting effect concentration range（RCS） and the none-reaction concentration of single bacteria solution were narrower or lower than those of the mixed bacteria solution 4.0×10^-5—8.7×10^-5 mol·L^-1 of SCP were inhibited the mutation of single bacteria solution but obviously promoted the mutation of the mixed bacteria solution compared to the blank group（P〈0.05）.1.9×10^-5—6.3×10^-5 mol·L^-1 of SCP promoted the mutation of the mixed bacteria solution,which indicates more severe risk in selecting resistance SCP at 6.3×10^-5—1.5×10^-4 mol·L^-1 showed distinct inhibition of RP4 and R388 plasmid conjugation,which suggests that the concentration of SCP in this experiment shows little risk in conjugation.In summary,the effects of single bacteria solution are not sufficient to explain the mutation risk of sulfonamides in the environment,and we should use the mixture of sulfonamide-resistant E.coli and sulfonamide-susceptible E.coli to study the impact of sulfonamides on the transmission of ARGs.Our experiment has proved that low concentration of SCP in the environment have great risk in boosting the production of ARGs.