一株类芽孢杆菌的分离鉴定及其抗革兰氏阴性菌活性测定

【背景】随着碳青霉烯类和多粘菌素类可转移耐药基因的发现及扩散,多重耐药革兰氏阴性细菌感染更加难以治疗。【目的】筛选有效拮抗革兰氏阴性菌的菌株,为新型抗生素的发掘奠定基础。【方法】利用胰蛋白胨大豆琼脂培养基筛选土壤源细菌,通过16S rRNA基因序列鉴定其种属;通过全基因组测序,antiSMASH比对分析菌株产抗生素潜能,双层琼脂平板法验证其抗菌活性;通过甲醇萃取其次级代谢产物,高效液相色谱串联质谱(HPLC-MS/MS)进行次级代谢产物分析。【结果】从北京周边土壤样品中分离到一株类芽孢杆菌CAU136 (Paenibacillus pabuli CAU136),经过生物信息学分析和antiSMASH比对,表明该菌株有较强合成次级代谢产物的潜能,双层琼脂平板法验证其能抑制多株革兰氏阴性菌生长,HPLC-MS/MS检测结果显示其可能分泌多粘菌素E。【结论】类芽孢杆菌CAU136可能分泌多粘菌素E,能有效拮抗革兰氏阴性菌。

Characterization of Paenibacillus pabuli and its antibacterial activity against Gram-negative bacteria

Background] The emergence and dissemination of new mobile antibiotic resistance genes such as ndm and mcr, poses a great threat to the treatment of infections associated with multi-drug resistant Gram-negative bacterial pathogens. Objective] To screen new antibiotics, bacterial candidates were isolated and characterized against Gram-negative bacteria. Methods] First, bacterial strains were isolated from soils using tryptic soy agar (TSA), and identified by 16S rRNA gene sequencing. Then, bioinformatics analysis was performed based on the whole genome. Meanwhile, the secondary metabolites of the candidate strains were predicted by antiSMASH and antibacterial activity was confirmed by the double layer agar plate assay. Finally, the crude was extracted in methanol and identified using HPLC-MS/MS. Results] Paenibacillus pabuli CAU136 was isolated from the soil in Beijing, China. The whole genome sequence and antiSMASH analysis showed the great potential of P. pabuli CAU136 to produce secondary metabolites against bacteria. P. pabuli CAU136 showed antibacterial activity against different Gram-negative bacterial strains using the double layer agar plate method. Colistin in the crude extracts of P. pabuli CAU136 was demonstrated based on HPLC-MS/MS analysis. Conclusion] P. pabuli CAU136 may produce colistin against diverse Gram-negative bacterial strains.