Detection Of Drug Resistance And Drug Resistance Genes Of Goose-origin Salmonella And Therapeutic Test In Liaoning And Jilin Regions

Goose salmonellosis,also known as goose paratyphoid fever,is a bacterial infectious disease with fast transmission and high incidence.Goslings within 3 weeks of age have the highest infection rate and the mortality rate as high as 80%.Adult geese tend to be negative and the main source of infection.This disease is difficult to control once occured due to its wide transmission.In recent years,with the continuous development of the goose industry,more and more attention has been paid to the prevention and treatment of goose-origin salmonellosis.Except vaccine immunization,comprehensive biosecurity measures,the application of antibiotics has played an important role in prevention and control of this disease,but there emerged a serious problem of drug resistance.In this study,we investigated the relationship between the phenotype of Salmonella serovar and the drug-resistant genes using serotype identification,drug resistance test,drug resistance gene detection,and challenge and Therapeutic test,preliminary screened the appropriate therapeutic drugs,and therefore provide a theoretical basis for prevention and treatment of salmonellosis.In this experiment,43 suspected Salmonella strains isolated from 8 goose farms in Liaoning and Jilin Province were selectively cultured,identified by PCR and serotyped to obtain goose-origin Salmonella strains.The susceptibility of goose-origin Salmonella to 12antibacterials was detected by disk diffusion method,and 29 drug-resistant genes corresponding to beta-lactams and aminoglycosides were detected by PCR.Drug resistance spectrum and drug resistance gene of Salmonella were obtained.Two strains of goose-origin Salmonella with high detection rate were selected to challenge 3-day-old SPF chickens.Firstly,the chickens were inoculated with 10 times dilution of sterile saline solution and 5concentration gradients.Each chicken was inoculated orally with 500?L bacterial solution to observe and record the physiological status and count the death rate.Sixty-three 3-day-old SPF chickens were randomly divided into 7 groups with 9 chickens in each group.Group A was blank group,each chicken was given 500?L sterile saline;Group B and E was the control group,and Each chick was administrated with 500?L of the test strain I and the test strain II to be tested.The chicken in group C and group D were given the tested strain I?same dose and concentration as group B?,and the chicks in group F and group G were given with the tested strain II?same dose and concentration as group E?,respectively.12 h after challenged,Group C and group F were given SHALINING 50?L,group D and group G were given cefotaxime?0.015 mg/g per chick?.Three chickens in each group were killed on the 1st,4th and 7th day after administration,respectively.The visceral changes of chickens were observed,and the liver and cecum were collected to detect the bacterial load.The results were as follows:21 strains of Salmonella typhimurium were obtained through selective culture,PCR identification and serotype detection.They were 7 strains of Salmonella typhi,3 strains of Salmonella paratyphi A,2 strains of Salmonella paratyphi,Salmonella derby and Agung Nacer Mens,Salmonella typhimurium,Dan Bo Xun Shamen S,Salmonella,and cholera.The drug susceptibility test showed that the resistance rates of various antibacterials were amoxicillin?85.7%?,tetracycline?81%?,sulfanilamide isositic?81%?,florfenicol?71.4%?,chloramphenicol?76.2%?,kanamycin?47.6%?,gentamicin?38.1%?,norfloxacin?19%?,ciprofloxacin?4.8%?and cefotaxime?4.8%?.8%,cefoperazone?0%?and polymyxin B?0%?.The problem of multiple drug resistance is much serious,the highest tolerance to eight drugs.The detection of resistance genes showed that 11 of the 29resistance genes were detected,more than half of which accounted for 80%.This indicated that the resistance genes were widely spread in goose-origin Salmonella.The coincidence rates of the resistance phenotypes of tetracyclines,sulfonamides,and chloramphenicol and Peptides with the corresponding resistance genes were 81%,52.4%,23.8%,4.8%and 0%,respectively.it suggested that the drug resistance of goose-origin Salmonella has a certain relationship with the corresponding drug resistance genes.The median lethal dose(LD₅₀)of Salmonella spp.and Salmonella spp.were 4.40×10⁶ CFU/m L and 1.43×10⁷ CFU/m L,respectively.Cefotaxime and SHALINING had good antibacterial effects.Both of them could be used to treat goose-borne salmonellosis in Liaoning and Jilin province,but for Salmonella paratyphoid B,the effect of SHLINING was more significant than Cefotaxime during early days,and both of them were effective in 7 days.For Salmonella typhimurium,cefotaxime had a better effect than SHALINING at 4 days.For the liver,the effect of cefotaxime was more significant than SHALINING at 4 days.While for cecum,two medicines all showed obvious effect at the early stage,then gradually weakened,and there was no significant difference at 7days.Tissue lesions are mainly manifested in local liver cell degeneration,necrosis,inflammatory cell infiltration,and a large number of paratyphoid nodules.The cecal intestinal mucosal epithelial cells are degenerated and exfoliated,the villi are broken,the goblet cells are increased,and the inflammatory cells are infiltrated.After treatment,tissue lesions were significantly alleviated.In conclusion,the drug resistance of goose-origin Salmonella in Liaoning and Jilin provinces is serious,and the drug resistance has a certain relationship with its carried drug resistance genes;cefotaxime and SHALINING have good antibacterial effect and can be used to treat goose-borne salmonellosis in goose farms in Liaoning and Jilin provinces.