杭州地区牛乳源大肠杆菌的分离鉴定及木糖醇联用抗菌肽对生物被膜形成的干预

Isolation and identification of Escherichia coli from cow milk in Hangzhou and intervention of xylitol combined with antimicrobial peptides on biofilm formation

旨在调查杭州地区牛乳源大肠杆菌的流行情况,并探究木糖醇联用抗菌肽对引起奶牛乳房炎的大肠杆菌生物被膜形成的影响。通过麦康凯选择性培养基分离、革兰染色、生化试验、PCR方法鉴定牛乳源大肠杆菌,并采用刚果红平板试验和结晶紫染色法评价大肠杆菌生物被膜形成能力,选取生物被膜形成能力强的典型菌株,采用内置载体片法构建生物被膜,测定木糖醇和抗菌肽联用对大肠杆菌生物被膜的最小抑菌浓度(MBIC)和最小杀菌浓度(MBEC),最后通过扫描电镜分析木糖醇联用抗菌肽对大肠杆菌生物被膜干预的影响。结果显示:杭州地区牛乳源大肠杆菌的分离率达49%,其中58.2%以上能形成生物被膜。当抗菌肽单独使用时,MBIC和MBEC较高;联用5%木糖醇后,MBIC和MBEC明显降低,表明可以减少抗菌肽的用量。另外,木糖醇和抗菌肽联用能明显降低生物被膜的形成,并且5%木糖醇能增强抗菌肽1037的杀菌作用。本研究表明,联用木糖醇和抗菌肽可能是一种有效的控制奶牛乳房炎的方法。

This study was to investigate the prevalence of bovine milk-derived Escherichia coli in the Hangzhou area and to investigate the effect of xylitol combined with antimicrobial peptides on the biofilm formation of E.coli causing mastitis in dairy cows.The biofilm formation ability of E.coli was evaluated by Congo red plate test and crystalline violet staining.Finally,the effect of xylitol in combination with antimi⁃crobial peptides on E.coli biofilm intervention was analyzed by scanning electron microscopy.The results showed that 49%of bovine milkderived E.coli were isolated in the Hangzhou area,of which more than 58.2%were able to form biofilms.When the antimicrobial peptide was used alone,its MBIC and MBEC were higher.However,when combined with 5%xylitol,its MBIC and MBEC were significantly lower;and therefore,the dosage of the antimicrobial peptide could be reduced.In addition,the combination of xylitol and antimicrobial peptide sig⁃nificantly reduced the formation of biofilm,and 5%xylitol enhanced the bactericidal effect of antimicrobial peptide 1037.In conclusion,the combination of xylitol and antimicrobial peptides might be an effective method for controlling mastitis in dairy cows.