Study on the toxicity characteristics of a clinical bloodstream isolate of Salmonella Telelkebir / 中国人兽共患病学报

ABSTRACT

The ICR(Institute of Cancer Research)mouse infection model was constructed to study the pathogenicity of Sal-monella Telelkebir serotype,and the pathogenic identification of mouse isolates was carried out.Observe the bacterial excretion cycle,evaluate the pathogenicity of Salmonella serotype to mice,and calculate the LD50 by the changes in clinical characteris-tics,histopathology and tissue bacterial load of infected mice;by flight mass spectrometry,biochemical identification,serotype identification,molecular typing and other experiments,compared with human isolates;virulence gene analysis was carried out by PCR experiment and whole genome sequencing.The LD50 of Salmonella Telelkebir is 2.67 × 108 CFU/mL;curling and fluffing may occur 0.5 h after infection;autopsy of dead mice showed that the small intestine was severely congested,with more bubbles and fluid accumulation,cecal necrosis,liver apical degeneration and necrosis,necrotic foci on the surface of the kidney and spleen atrophy;the bacterial load of spleen,kidney,lung,liver and jejunum in mice reached its peak at 3 days after infection,while that of heart at 6 days;the bacterial excretion time of the high-dose group exceeded 100 days;The level of CD3 in tissues increased with increasing dose,with inflammatory cell infiltration,myocardial capillary dilation and hyperemia,large area of vacuoles,degeneration and necrosis of hepatocytes,obvious enlargement of splenic sinus,blurred zoning,thickening of glomerular basement membrane,partial exfoliation of ciliated epithelium,atrophy and exfoliation of jejunal villi;PCR and whole genome sequencing revealed Salmonella-related virulence genes such as cdtB,plt A and pltB.This study was the first to successfully establish the ICR mouse model of Salmonella Telelkebir,demonstrating that this serotype of Salmonella has some pathogenicity.