食品中单核细胞增生李斯特菌分离及药敏试验的研究

Isolation of Listeria moncytogenes from food and test of drug susceptibility.

目的 了解食品中单核细胞增生李斯特氏菌 (Lm)的污染状况及药敏情况。 方法 菌株分离鉴定应用国家卫生标准检验方法、API法和多聚酶链反应 (PCR) ;药敏试验采用Kirby -Bauer法。 结果 李斯特氏菌 (李氏菌 )总污染率为 5 18% ( 16/ 3 0 9) ,其中生肉和水产品均为 8%、熟肉制品为 11 5 1%、生牛奶为 3 5 1%、乳制品和蔬菜均未检出 ,Lm检出率为 1 2 9% ( 4 / 3 0 9) ,经PCR测定 4株Lm同时含有内化素基因和李氏溶血素O基因 ,并且溶血试验与小鼠致病力试验均为阳性。药敏试验选用 12种抗生素 ,4株Lm对庆大霉素、万古霉素、卡那霉素、诺氟沙星、氧氟沙星、红霉素、氯霉素、四环素、头孢噻吩、头孢唑啉敏感 ;对依诺沙星和呋喃妥因耐药。 结论 李氏菌在多种食品中均有不同程度的污染 ,4株Lm小鼠致病力阳性 ;溶血试验和PCR测定的溶血素基因是鉴别Lm的一个重要方法 ,Lm对多种抗生素敏感 。

Objective To understand the status of food cantamination with Listeria monocytogenes (Lm) and its resistance to antibiotics. Methods LM strains were, based on national standard test and API test isolated by using PCR technique. The sensitivity of Lm to antibiotics was also determined by using Kirby-Baucer technique. Results The total detected rate of contamination with Listeria was 5.18%(16/309), of which contamination rates of uncooked meat, aquatic products, cooked meat products, fresh milk were 8%,8%,11.51% and 3.51%, respectively,and no Listeria was detected in milk products and vegetables. The detection rate of Lm was 1.29%(4/309). The strains of Lm contained internalin gene and Listeria lysine O-gene,and the results of hemolysis test as well as pathogenic test on mice were also positive. Tests of the sensitivity of Lm to 12 antibiotics including gentamycin, vacomycin, kanamcin,B, norrfloxacin, Ofloxacin, erythromycin, chloramphenicol, tetramycycline, hydrochloride and cefazolin were carried out. Resistance to enoxcin and nitrofurantion was observed. Conclusion Contamination with various extent of Lm was observed in a number of foods. Hemolysis test and PCR technique are the important methods for determination of food contamination with Lm. Lm is resistant to enoxcin and nitrofurantoin but still sensitive to other antibiotics tested.