南宁某奶牛场乳房炎监测与病原调查

发布时间：2018-07-14 07:29

【摘要】：奶牛乳房炎(Bovine mastitis)在奶牛养殖业中是多见的疾病之一,它造成奶产量的减产以及低劣的原料乳,常常引发一些公共卫生学问题与食品安全问题,奶牛乳房炎造成的危害,对于奶牛养殖户,乳品加工行业来说都是一个非常沉重的经济压力。本次实验的奶样都来至于南宁某奶牛场,样品先进行乳汁质量的检测;再进行奶牛乳房炎主要病原菌分离鉴定及药敏试验;使用PCR检测金黄色葡萄球菌的毒力基因和耐药基因。具体研究如下:试验一:乳房炎与乳汁质量的动态监测在2014年10月至2016年10月间,每月(个别月份缺失)定期随机采集奶样,应用荷兰产DEITA牌Somascope SmartTM体细胞检测仪对奶样进行乳汁体细胞计数,按不同SCC分类,SCC在50～100万/ml为隐性乳房炎。SCC50万/ml为正常乳汁,SCC数量越少,提示牛奶质量越好。统计分析不同时期奶牛乳房炎的发生情况以及牛奶质量情况。结果表明:不同泌乳月份奶牛个体SCC变化不同,泌乳月份奶牛个体乳SCC呈波动性变化。总体上来看,不同泌乳月份奶牛体乳SCC变化不同,泌乳月份奶牛体乳SCC呈波动性变化,奶牛夏季体乳SCC呈波动性变化最为明显,冬季体乳SCC呈波动性最小。在这20个月中,奶质逐渐变好,其中2016年的奶质是最好的。夏季、秋季的体细胞数比春季、冬季的高。合格奶样整体呈现上升的走势,不合格奶样整体也是呈现下降的走势。试验二:奶牛乳房炎主要病原菌分离鉴定与药敏试验通过细菌分离鉴定与生化鉴定,获156株可疑菌株,生化鉴定确定出金黄色葡萄球菌57株,占36.5%、无乳链球菌13株、停乳链球菌7株、乳房链球菌6株,链球菌占16.7%、大肠杆菌73株,占46.8%。其中金葡菌的耐药率是33.7%、链球菌的耐药率是31.1%、大肠杆菌的的耐药率是35.2%。链霉素、青霉素、四环素对大肠杆菌已经100%失去作用;链霉素、青霉素也对金黄色葡萄球菌已经是100%失去作用,恩诺沙星有较高的耐药性,而对氨苄西林、羧苄西林、多西环素产生部分不敏感;链球菌对氨苄西林、链霉素、青霉素、红霉素已经100%耐药,但三类菌对丁胺卡那、羧苄西林、头孢哌酮、头孢曲松、氧氟沙星都具有较高敏感性。试验三:金黄色葡萄球菌毒力基因检测对上述生化鉴定的57株黄色葡萄球菌,再利用PCR检测它的nuc、h1a、h1b、sea、seb毒力基因,nuc基因仅为金黄色葡萄球菌所具有而且具有高度保守性。结果表明:携带nuc基因的有57株(100%,)携带H1a基因的有13株(22.8%),携带H1b基因的有15株(23.6%)。同时携带有两种的占7.0%。携带sea基因的有12株(21.1%),携带seb基因的有8株(14.0%),同时携带有两种基因的占3.5%。在食品安全问题上,仍需要重视。试验四:金黄色葡萄球菌耐药基因检测金黄色葡萄球菌是引起奶牛乳房炎最主要的病原菌之一,由于其感染率高,且呈现多重耐药性。通过在线软件设计金黄色葡萄球菌的红霉素耐药基因ermB、ermC和耐甲氧西林金黄色葡萄球mecA基因的引物,使用PCR检测,ermB、ermC毒力基因,结果表明:携带ermB基因的有10株(17.5%),ermC基因的有16株(28.1%),57株金黄色葡萄球菌基因的PCR检测,未检测到携带mecA基因。科学合理的使用抗生素,尽量避免耐药株的产生。
[Abstract]:The dairy cow mastitis (Bovine mastitis) is one of the most common diseases in the dairy farming industry. It causes the reduction of milk production and the poor raw milk. It often causes some public health problems and food safety problems, and the harm caused by dairy cow mastitis. It is a very heavy classics for dairy farmers and dairy industry. The milk sample of this experiment came to a dairy farm in Nanning, the samples were first tested for milk quality, and the main pathogenic bacteria of Dairy Mastitis were separated and identified and the drug sensitivity test was carried out. PCR was used to detect the virulence genes and resistance genes of Staphylococcus aureus. Milk samples were collected regularly from October 2014 to October 2016. The milk samples were counted with the DEITA Somascope SmartTM somatic cell detector produced in Holland. According to different SCC classification, SCC was 50~100 million /ml as recessive mastitis.SCC50 million /ml as normal milk, and the less SCC, indicating milk quality. The quality of dairy cow mastitis and milk quality in different period of milking were analyzed. The results showed that the individual SCC changes of dairy cows in different lactation months were different, and the individual milk SCC of dairy cows fluctuated in month of lactation. On the whole, the SCC changes of dairy cows in different lactation months were different, and the milk SCC of dairy cows was fluctuant in lactating month. During the summer, milk quality was the least. In the 20 months, milk quality became better. In the 20 months, milk quality became better. In 2016, the milk quality was the best. In summer, the number of somatic cells in autumn was higher than that in spring and winter. Trend. Test two: the main pathogen isolation and identification and drug sensitivity test of dairy cow mastitis, 156 strains of Staphylococcus aureus, 13 strains of Streptococcus Lactococcus, 7 Streptococcus, 6 Streptococcus, 16.7% Streptococcus, 73 strains of Escherichia coli, and 73 strains of Escherichia coli, were identified by bacterial isolation and biochemical identification, 57 strains of Staphylococcus aureus, 13 Streptococcus, 7 Streptococcus, 6 strains of Streptococcus, 16.7% Streptococcus, 73 strains of Escherichia coli, 46.8%. The resistance rate of Staphylococcus aureus was 33.7%, the drug resistance rate of Streptococcus was 31.1%, the resistance rate of Escherichia coli was 35.2%. streptomycin, penicillin, and tetracycline had lost 100% effect on Escherichia coli; streptomycin, penicillin had also lost 100% to Staphylococcus aureus, and enrofloxacin was highly resistant to ampicillin and carboxyl. In benzicillin, doxycycline produced partial insensitivity; Streptococcus has 100% resistance to ampicillin, streptomycin, penicillin and erythromycin, but three types of bacteria have high sensitivity to amikacin, cicillin, cefoperazone, ceftriaxone and ofloxacin. Test three: 57 strains of Staphylococcus aureus virulence gene test for the above biochemical identification Staphylococcus aureus, and then using PCR to detect its NUC, H1a, H1B, sea, SEB virulence genes, the NUC gene is only with Staphylococcus aureus and highly conserved. The results show that 57 (100%) carrying the H1a gene carrying NUC (22.8%), and 15 (23.6%) carrying H1b genes, and two kinds of 7.0%. carrying the gene. 12 (21.1%) with sea gene, 8 (14%) carrying SEB gene and two genes in the food safety problem, still need to be paid attention to. Test four: Staphylococcus aureus resistance gene detection of Staphylococcus aureus is one of the most important pathogens causing cow mastitis, because of its high infection rate and more than one. Heavy drug resistance. Primers for the erythromycin resistant gene ermB, ermC and methicillin resistant Staphylococcus aureus mecA gene were designed by online software, and PCR detection, ermB, ermC virulence genes were used. The results showed that 10 (17.5%), 16 (28.1%) of ermC gene and 57 strains of Staphylococcus aureus gene were in PC, and 57 strains of Staphylococcus aureus. R detection showed that mecA gene was not detected. Scientific and rational use of antibiotics should be avoided as far as possible.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S858.23

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