| Salmonella,a gram-negative bacterium that causes typhoid and paratyphoid in humans and animals,is of great significance in public health.Salmonella can cause pullorosis in chickens,paratyphoid fever in pigs and abortion in sheep.Salmonella infection in rabbits can cause loss of appetite,diarrhea,female miscarriage and death of newborn rabbits.At present,although the salmonella enteritidis in rabbits can be effectively controlled by antibiotics,such as cefotaxime,enoxacin and oxytetracycline,the resistance of the rabbit salmonella enteritis is still not very clear in the case of increasingly serious drug resistance of the salmonella.In addition,there is no vaccine for the prevention and control of salmonella enteritidis in rabbits.Our research mainly studied rabbit salmonella enteritis from three aspects:1.Isolation,identification and epidemiological investigation of salmonella enteritis in rabbitsSince March 2017,there have been outbreaks of female rabbits aborting and newborn rabbits dying in rabbit farms in Jiangsu,Shandong and Jilin provinces.Clinical samples were isolated,cultured and identified by our laboratory.The results showed that the rabbits from these farms were infected with salmonella enteritis.MLST typing of salmonella enteritis indicated that the salmonella were all the type of ST11.Then further analysis showed that the Shandong province has the highest incident rate.2.Resistance phenotype test and resistance gene detection of salmonella enteritis in rabbitsEight strains of salmonella enteritis from four different regions were selected and analyzed for drug sensitivity test,and the results showed a severe drug resistance.According to the analysis of the drug resistance spectrum,among the 15 drugs,the drug resistance spectrum of the 8 isolates with the least amount was 6,and the highest was 14.The detection results of drug resistance genes showed that blaTEM drug resistance genes in?-lactam drug resistance genes could be detected in all 8 isolated strains,while the drug resistance genes blaPSE could not be detected.The detection rates of aminoglycoside resistant genes aadA1,aadA2,aph(3)-ila were 12.5%,37.5%and 100%,respectively.The detection rate of quinolone-resistant gene qnrA and qnrB was 25%and 37.5%respectively.The detection rate of sulfanilamide resistance gene sull was 100%,and that of sulfanilamide resistance gene sul3 was 75%.ErmA and mefA of macrolides resistance gene were negative.TetA,tetB,tetM and tetX of tetracycline resistance gene were also negative.The detection rate of tetC resistance genes was 37.5%and that of tetG resistance genes was 12.5%.The detection rate of chloramphenicol FloR resistant gene was 12.5%.In addition,oqxA and oqxB genes of bacterial multidrug resistance efflux pump of great clinical significance were positive.in this study,but oqxB was negative,and the detection rate of oqxA resistance gene was 100%.3.Virulence determination and virulence gene detection of salmonella enteritis in rabbitsThe islands virulence genes and plasmid virulence genes of 8 strains of salmonella enteritis were detected.The test results showed that the 8 strains of rabbit salmonella enteritidis spvR plasmid virulence genes,spvA,spvB,spvC,spvD,had a 100%detection rate.The detection rate of virulence genes hilA,siiE,sopB,invH,sopA,sopD,avrA,hilA,iacP,prgK,sscL,ssrA,misL,orf319,siiE,siiA,sopB,pipC was also 100%,but sugR,rmbA,ssaB were 0%.Therefore,there was no difference in virulence gene levels among these 8 strains of salmonella enteritis.The results showed that field A in Shandong had the strongest virulence(2×108 cfu,dead 5),and field C in Jiangsu had the weakest virulence(2×108 cfu,dead 1).In this study,the virulence and virulence genes of each strain of salmonella enteritis in rabbits were detected,which laid a foundation for future studies on the virulence of salmonella enteritis in rabbit and the attenuated vaccine. |
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