鲜牛奶中细菌的分离纯化及其药物敏感性分析

为了解鲜牛奶中细菌的分布情况及其对抗生素的敏感状况,实验对30份采自河北张家口地区某养殖场的新鲜无菌牛奶进行细菌分离鉴定,并分别用青霉素(16μg/ml)、氯霉素(32μg/ml)、克林霉素(4μg/ml)、红霉素(8μg/ml)、四环素(16μg/ml)、庆大霉素(16μg/ml)、环丙沙星(4μg/ml)、头孢噻吩(32μg/m)l进行药敏实验。结果显示30份牛奶样品中共分离得到111株菌,分别为葡萄球菌31株、沙雷氏菌14株、假单胞菌12株、芽孢杆菌11株、肠杆菌5株、不动杆菌4株、奇异变形杆菌3株、微球菌3株、巨球菌3株、肠球菌4株、其它菌21株。其中耐青霉素16μg/ml的为50株,耐氯霉素32μg/ml的为23株,耐克林霉素4μg/ml的为46株,耐红霉素8μg/ml的为37株,耐四环素16μg/ml的为38株,耐庆大霉素16μg/ml的是7株,耐环丙沙星4μg/ml的为8株,耐头孢噻吩32μg/ml的为40株。通过实验可知,细菌类型主要有葡萄球菌、沙雷氏菌、假单胞菌等;8种抗生素中,庆大霉素、环丙沙星、氯霉素的抑菌效果较好,而青霉素、克林霉素、红霉素、四环素、头孢噻吩的抑菌效果相对较差。

Separation,identification and antimicrobial susceptibility testing of bacteria from fresh milk

To understand the distribution of bacteria in fresh milk and their sensitivity to antibiotics,bacteria from 30 samples collected from Zhangjiakou area was isolated and identified.With penicillin(16 μg/ml),chloramphenicol(32 μg/ml),clindamycin(4 μg/ml),erythromycin(8 μg/ml),tetracycline(16 μg/ml),gentamicin(16 μg/ml),ciprofloxacin(4 μg/ml),cephalothin(32 μg/ml) for susceptibility testing,respectively.111 strains were isolated from 30 samples contained 31 Staphylococcus,14 Serratia,12 Pseudomonas,11 Bacillaceae,5 Enterobacter,4 Acinetobacter,3 Proteus mirabilis,3 Micrococcus,3 Macrococcus,4 Enterococcus and 21 other bacteria.50 strains showed antibiotic resistance to Penicillin,23 strains showed antibiotic resistance to chloramphenicol,46 strains showed antibiotic resistance to clindamycin,37 strains showed antibiotic resistance to erythromycin,38 strains showed antibiotic resistance to tetracycline,7 strains showed antibiotic resistance to gentamicin,8 strains showed antibiotic resistance to ciprofloxacin,40 strains showed antibiotic resistance to cephalothin.The results of the experiment indicated that the main types of the bacteria were Staphylococcus,Serratia,Pseudomonas etc.The effect of gentamicin,ciprofloxacin and chloramphenicol were better,and penicillin,tetracycline,clindamycin,erythromycin and cephalothin were relatively poor.