| Animal bacterial diarrhea is one of the important infectious diseases of livestock and poultry industry.Antibiotics are used for the main treatments and precautions to forbid this diseases.In recent years,because of the abuse of antibiotics,the drug-resistance of pathogenic bacteria becomes more and more serious,so it is urgently need to find a medical material to assist or even replace antibiotics.Copper ion has good antibacterial property,it can inhibit the growth of many pathogens,and the meantime its inhibition of harmful fungi is also very prominent.Attapulgite clay has good adsorption.Its unique crystal structure and larger specific surface make it performe very well in terms of adsorption of bacterial and toxins.The both of advantages were combined in this experiment,and the attapulgite clay ion-modified with copper was prepared as inorganic antibacterial,in order to study its antibacterial properties to pathogenic Salmonella in vitro and assess the curative effect on bacterial diarrhea in mice,so as to provide theoretical basis for a new drug to bacterial diarrhea.Five strains of Salmonella were isolated from nine diarrhea dogs in Animal Hospital of Nanjing Agricultural University,and identified by biochemical test and PCR amplification with a pair of specific primers designed according to the Salmonella invA gene.Serotype distribution and susceptibility to drugs were investigated.The results showed that there are four strains belong to S.typhimurium,and only one strains belongs to S.eastbourne.Two serotypes of Salmonella were both sensitive to Amikacin,Cefoxitin,Streptomycin,Cefepime,but resisted to Ampicillin,chloramphenicol and sulfa drugs.And the result of pathogenicity test showed that isolated strain S.typhimurium was stronger than S.eastbourne.Modified attapulgite by copper ion(Cu2u)with the liquid ion-excharged method was studied in this paper.The study was mainly about finding the optimal technological parameters of modification.And also using X-ray diffraction to analyze "whether-modification changed the crystal structure of attapulgite or not.The result showed that the concentration of the initial reactant was 0.15 mol/L,the temperature of the reaction was 90 ℃,and the duration of modification was 6 hours,the copper ion content was 51.25 mg/g.And an experimental result of XRD showed that the primary crystal sturcture of copper ion-modified attapulgite was similar to that of attapulgite.The aim of antibacterial inhibition study in vitro was mainly to assess the antibacterial properties of copper ion-modified attapulgite to pathogenic Salmonella.The result showedthat the antibacterial inhibition ratio of attapulgite modified by Cu2T could reach 50～100%,and attapulgite could reach only 26～56%.The antibacterial properties of copper ion-modified attapulgite improved significantly(P<0.01).And the copper ion content was greater;the antibacterial inhibition ratio was higher.Use pathogenic Salmonella to establish diarrhea in 70 ICR random grouping mice.Then feed copper ion-modified attapulgite(8 mg/mL)to each one,and other control groups treated with the same way.The results show that the copper ion-modified attapulgite could significantly inhibit bacterial diarrhea(P<0.01),and at the same time for the repair function of intestinal mucosa was superior to that of other control group(P<0.05).This study showed that copper ion-modified attapulgite crystal structure had not changed,at the same time the antibacterial properties were improved significantly.The treatment using modified clay to bacterial diarrhea was remarkable,and gastroin testinal mucosa was repaired effectively.The market prospect of the modified clay will be prosperous. |
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