一多重耐药单增李斯特菌株的生长特性及毒力分析

为了解单增李斯特菌株耐药后可能发生的生物学变化,以哈市生肉中分离到的1株对17种抗生素耐受的单增李斯特菌株L.M.B8为研究对象,对其生长及毒力特性进行研究。结果显示,L.M.B8的生长及毒力特性均与标准菌株有明显差异。在NaC l浓度为0.5%~5%、pH值为4.0~10.0及温度为20~45℃范围内,L.M.B8的生长速度均明显高于标准菌株。L.M.B8对高浓度盐的敏感性高于标准菌株,且对温度的适应能力强于标准菌株。从生长曲线看,L.M.B8的对数生长期与稳定期均较标准菌株提前2~3 h,且其稳定期较标准菌株明显缩短。L.M.B8小鼠腹腔注射半数致死量（LD50）较标准菌株明显降低。该研究为进一步探讨单增李斯特菌的耐药性与其他生物学特性的相关性奠定基础。

Growth Characteristics and Virulence Analysis of a Multidrug-Resistant Listeria monocytogenes

In order to learn the possible biological changes in Listeria monocytogenes(Lm) after having drug-resistance,Lm strains L.M.B8 that resisted against 17 antibiotics isolated from raw meats in Harbin markets was chosen as research target and studied on its growth and virulence characteristics.The results showed the growth and virulence characteristics of L.M.B8 had tangible difference with the standard strain.Its growth rate was tangibly faster than the standard strain in range of 0.5%～5% NaCl,pH 4.0~10.0,and 20~45 ℃.L.M.B8 was more sensitive to high concentrations salt than the standard strain and its adaptability to temperature was stronger than the standard strain.View from growth curve indicated that its logarithmic phase and stable phase advanced for 2~3 h and its stable phase was obviously shorter as compared with the standard strain.LD50 of L.M.B8 in mice by intraperitoneal injection was markedly lower than the standard strain.This study would lay a foundation for further study on the pertinence between drug resistance and other biological characteristics of Listeria monocytogenes.