金黄色葡萄球菌对苯扎溴铵敏感性与生物被膜形成能力相关性分析

Correlation Analysis of Benzalkonium Bromide Sensitivity and Biofilm Formation Ability in Staphylococcus aureus

以35株生猪屠宰场及养殖场来源的金黄色葡萄球菌分离菌株为试验材料,分析金黄色葡萄球菌对苯扎溴铵敏感性与生物被膜形成能力的相关性。采用微量肉汤稀释法检测金黄色葡萄球菌对苯扎溴铵的敏感性,结晶紫染色法检测生物被膜形成能力,基于全基因组测序结果分析屠宰环节的26株金黄色葡萄球菌多位点序列分型(multi-locus sequence typing,MLST)情况,以及消毒剂抗性与生物被膜形成相关基因的携带情况。结果表明,35株菌中,苯扎溴铵的最小杀菌浓度(minimum bactericidal concentration,MBC)范围为1~16 mg·L^(-1),强成膜能力菌株共16株,占总数的45.71%(16/35),其中93.75%(15/16)来自于屠宰链的下游。ST7是强成膜能力菌株的优势序列型(93.75%,15/16)。金黄色葡萄球菌生物被膜形成能力和苯扎溴铵MBC值呈正相关(相关系数为0.690),而消毒剂抗性与相关基因携带情况无关。综上,金黄色葡萄球菌可通过形成生物被膜提高对消毒剂的耐受性,减弱了苯扎溴铵的消毒效果,增加了养殖和屠宰环节中细菌污染和传播的风险。

Overall 35 strains of Staphylococcus aureus(S.aureus)isolated from one pig slaughterhouse and different pig farms were used as experimental materials to analyze the correlation between the susceptibility of benzalkonium bromide and the biofilm formation ability.Sensitivity to benzalkonium bromide and ability to form biofilms of S.aureus strains were determined using the micro-dilution broth method and the crystal violet staining test,respectively.The multi-locus sequence typing(MLST)and the carrying of genes related to disinfectant resistance and biofilm formation of 26 strains of S.aureus from the slaughterhouse were analyzed based on whole-genome sequences.The results showed that among the 35 strains,the minimum bactericidal concentration(MBC)of benzalkonium bromide ranged from 1 to 16 mg·L^(-1),and there were 16 strains with strong biofilm-forming ability,accounting for 45.71%(16/35)of the total,of which 93.75%(15/16)were recovered samples collected from downstream in the slaughter chain.ST7 was the dominant type of S.aureus with strong biofilm-forming ability(93.75%,15/16).The benzalkonium bromide MBC value of S.aureus was positively correlated with biofilm formation ability(Correlation coefficient=0.690),not with the disinfectance has nothing to do with the gene.In conclusion,biofilm formation may increase S.aureus resistance to disinfectants,weaken the disinfection effect of benzalkonium bromide,thus enhance the risk of bacterial contamination and transmission in breeding and slaughtering.