| Salmonellosis is the generic terms for host diseases caused by different kinds of salmonella,and it can induce typhoid fever,paratyphoid fever,diarrhea,abortion and other diseases as well as human diarrhea,typhoid,septicemia,food poisoning,paratyphoid and so on.Salmonellosis has been found so far,mainly through the treatment and prevention of antibiotics.Especially in the middle of the 20th century,antibiotics were widely abused and drug-resistant strains began to emerge,becoming one of the most urgent public health problems in the world.At present,there are many studies on salmonellosis in poultry and human,and relatively few studies and reports on salmonellosis in rabbits.China is the first country in the production and export of rabbit meat.The occurrence and prevalence of salmonellosis in rabbits will not only bring huge economic losses to the rabbit industry,but also bring serious public health and safety problems.This study mainly focused on two aspects of Salmonella enteritidis in rabbits,the main research contents are as follows:1.Isolation,identification and prevention of salmonella enteritis in rabbitsIn February 2017,a infectious disease occurred in a warren of Shandong province,whose main clinical features was female rabbit abortion or death and weaning rabbit splenomegaly or death.It was preliminarily diagnosed to be salmonellosis and laboratory diagnosed to be Salmonella enteritidis infection.We identified a set of rapid and accurate methods for Salmonella enteritidis detection in rabbits.Then the methods were used for Salmonella enteritidis detection of samples from another two rabbit hutches of the warren,branch warrens,and the neighboring warrens.Then the isolates were identified MLST sequence types and laboratory inactivated vaccine preparation,safety test,attack model test,primary immunization and secondary immunosuppression efficacy evaluation test,clinical immunity test.The detection rates of Salmonella enteritidis in different warrens were 10.30%-73.33%.All the isolates belonged to the same sequence type,ST11.Immunization once and twice provided equal effective protection.Whereas,the immune effect of twice immunization was better than once immunization.This study provides experience and reference data for epidemiological investigation and prevention of rabbit salmonellosis.2.Study on the drug resistance of Salmonella enteritidis isolatesFrom two angles:phenotype and genotype,10 strains of Salmonella enteritis isolated from different warrens in Shandong area were studied and analyzed in this experiment,including drug sensitivity test,detection and location of related resistance genes,detection and localization of I integron resistant gene box,detection and location of transposon,etc.The test results showed that 10 strains of Salmonella enteritis were resistant to 2 or more than 2 kinds of antibiotics.The drug resistance of the isolated strains in different warrens was different.At the most,13 kinds of antibiotics were tolerant,and the multidrug resistance was serious.The 10 strains were the most resistant to the compound of sulfa,and the drug resistance rate was as high as 100%,followed by tetracycline and beta lactam,the average resistance rate was above 80%,and the sensitivity to amikacin,florfenicol and cefotaxime was the highest.The main drug-resistant spectrum of the 10 strains of Salmonella enteritis was PEN-AMP-LEX-KAN-TET-DOX-SXT;In addition to tetracycline and quinolones,the results of resistance gene detection of other antibiotics were consistent with drug resistance phenotype,with the highest detection rate of blatem-1,sull and sul2.Among the 10 strains,7 were the type I integration-positive strains,and the resistance types were above 8,and the detection of 440bp and 2900bp of the two types of drug-resistant gene boxes;The 10 multidrug-resistant strains were carried with different transposons,among which the detection rate of IS26 and tnpA was the highest,and tn1721 and tnpU were not detected.The multiple resistance of 10 strains of Salmonella enteritis is closely related to the resistance genes,I integrons and transposons,especially in chromosomes and plasmids,which are both hereditary and horizontal,causing multiple drug resistance to spread widely between genera and species,and the rate of bacterial multidrug resistance is greatly increased.This test by studying the relationship between the drug resistance related factors and multiple drug resistant strains of salmonella,analysis of drug resistance of salmonella situation and developing trend,to provide a theoretical basis for the clinical application of warrens and reference data for the study of the mechanism of multidrug resistance(MDR). |
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