Detection And Sequence Analysis Of Main Virulence Genes And Drug Resistance Gene Of Streptococcus Agalactiae Isolated From Cow Caused By Mastitis In Ningxia Region

The cow mastitis is one of the common disease endangering the healthy development of dairy farming. The disease increased the cow drop-out rates and health care cost of treatment, it has led to a serious of economic losses in dairy industry. According to concerning sectional statistic, Just because the cow mastitis cows accounted for 9% of the total elimination of cattle was eliminated-11%, economic losses caused by more than $13.5 billion every year in China. The cow mastitis pathogenic microorganisms, which are caused by complicated streptococcus and staphylococcus is the main pathogenic bacteria of dairy cow mastitis, Streptococcus and with no milk in the main proportion. according to the classification method of bacterium Streptococcus agalactiae belonging to the group B Streptococcus, the bacteria can cause not only animals such as cows, goats, sheep, mastitis, but also humen neonatal sepsis and meningitis and pneumonia, and cause a serious of damage to animal and human health. So diagnose and study the effective prevention and control of preparation rapidly and accurately for the control of dairy cow mastitis has important and far-reaching significance. 1. This experiment collecting a large number of mastitis milk sample from yinchuan and surrounding areas, by bacterial culture, morphological observation and biochemical experiment and a series of detection methods, A total of 266 strains of streptococcus was isolated..Then combining molecular biology identification method, Including 22 strains Streptococcus agalactiae,19 strains Streptococcu dysgalactiae 15 strains Streptococcus uberis.The experimental results show that the ningxia region in dairy cow mastitis streptococcus infection without separation, the highest rate of Streptococcus agalactiae.2. Using disc diffusion method recommended by CLSI, type of 22 strains of clinical Streptococcus agalactiae clinical isolates of 19 kinds of drug sensitive test. The results showed that the isolates of 19 kinds of antimicrobial agents have different degree of resistance which the sulfanilamide different oxazole resistant rate of 95.5%; Of compound new Ming resistant rate reached 77.3%; Of nalidixic acid and ampicillin resistant rate reached 68.2%; To tetracycline and clindamycin resistant rate reached 59.1%; For he totally cephalosporin resistant rate reached 54.5%; To clindamycin, carboxy ampicillin, norfloxacin resistant rate achieves 50%; Ni also reached more than 45% of amoxicillin. There were 18 kinds of additional 22 strains without milk streptococcus drug-resistant spectrum, does not appear 1,3 and 19 resistant strains. Which is the least amount of resistance type 2, only 1 strains (4.5%), the most is 9, resistant to eight strains (36.4%), the highest resistance of 12.3. According to the relevant sequence GenBank publicly, design sulfa sull and sul2, sul3 and tetracycline class tetE specific primer PCR reaction, PCR detection method are established. Results show that this method is sensitive and reliable, and can be used as a clinical test method used. Of 22 strains of clinical isolates were detected Streptococcus agalactiae, detected a total of 4 kinds of resistant genes, respectively:sull (18.2%), sul2 (22.7%), sul3 (27.3%), tetE (18.2%). This study of ningxia region Streptococcus agalactiae isolates sulfa drug resistance and tetracycline resistance gene detection, in order to prevent Streptococcus agalactiae resistance to provide scientific theoretical basis.4.22 strains of Streptococcus agalactiae, amplify the Sip, cpsE, CAMP, the three main virulence genes and sequencing, after the sequence were analyzed. Results show that the three genes and GenBank open sequence homology is very high, the Sip gene are more than 94%; homology cpsE gene was 99%; the CAMP gene are more than 98% homology.