Investigation On The Infection Of Ascaris Suum In Abattoirs And The Isolation And Analysis Of Bacteria In Ascaris Suum In Shaanxi Province

Asarissuum is a large nematode parasitic on the small intestine of pigs.It is prevalent all over the world,especially in underdeveloped areas and breeding areas with poor feeding environment where infection rate is extremely high,and human can also be infected with Ascaris lumbricoides.Asarissuum has low mortality,but it takes in host's nutrition on a long-term basis,causing great losses for pig industry.Although the study of virus in parasites has been reported,there are few reports on bacterium in parasites.Ascaris suumis a preferred model because of its oversize and convenience to many chemical test.To know the Ascaris suum infection in slaughter pigs in Shaanxi province,primarily investigate the interrelation between intestinal bacterium of Ascaris suum and intestinal flora of pigs,and further study the role that Ascaris suum plays in spreading bacteriosis,this paperanalyzed Ascaris suum infectionthrough the method of dissecting small intestines of slaughtered pigs in northern,central and southern Shannxi province.Bacterium of Ascaris suum intestine was isolated by traditional culture and 16 S rDNA was amplified,cloned,screened and sequenced to identify the bacterium.The bacteriostatic activity of Ascaris suum body fluid was detected by filter paper,and Cecropin P1 gene fragment was amplified by PCR from total DNA of Ascaris suum based on the PCR amplification of Cecropin P1 gene to Ascaris suumantibacterial peptides.The results are as follows.1.885 slaughterpigs from five slaughter houses in three regions,Shenmu(northern Shaanxi),Yangling,Zhouzhi(central Shaanxi),and Chenggu(southern Shaanxi)were detected the detection rates and infection intensity of Ascaris suum by small intestine subsection to analyze Ascaris suum infection of slaughter pigs in different regions of Shaanxi province.In addition,the divergence analysis was conducted to study Ascaris suum infection in different seasons in Zhouzhi slaughter house.Results showed the detection rates of Ascaris suumin different regions of Shaanxi were respectively Shenmu 4.29%(10/233),Yangling 150%(25/50),Yangling Bensun 0%(0/53),Zhouzhi 11.22%(45/401),Chenggu 4.05%(6/148).Ascaris suum average infection intensities were respectively Shenmu 1.30,Zhouzhi 4.77,Yangling 9.00,Chenggu 1.67.The detection rate of Ascaris suum and regional independence test showed there was extremely significant difference in detection rate of Ascaris suum indifferent regions of Shaanxi(P < 0.01).The detection rates in different seasons in Zhouzhiwere respectively autumn 9.94%(16/161),winter 12.71%(23/181),spring 10.00%(3/30),summer 10.34%(3/29),the average infection intensities were autumn 4.12,winter4.96,spring 6.67 and summer 5.00.The independence test showed there was insignificant difference in detection rates of Ascaris suum for slaughter pigs in different seasons(P>0.05).Results revealed Ascaris suum is prevalent in Shaanxi province and there is regional difference.2.Totally 7 strains of bacteria(no.HC1~HC7)were isolated from intestine of Ascaris suum.The identification showed HC1 was the same as HC2,so were HC3,HC4 and HC5,HC6 and HC7 were the same.The biochemical test and PCR amplification of 16 S rDNA identified HC1,HC3 and HC6 were Escherichia coli;By cloning and sequencing of bacterial16 S rDNA molecule,4 strains of bacteria were identified from intestine of Ascaris suum,namely,Anoxybacillus flavithermus,Romboutsia timonensis,Clostridium glycolicum,Luteimonas padinae,and 4 for perisoma of Ascaris suum,being Romboutsia timonensis,Ralstonia insidiosa,Pasteurella aeroqenes and Rombinsoniella peoriensis.Excluded the above bacteria,3 strains of bacteria were identified as Anoxybacillus flavithermus,Clostridium glycolicum,Luteimonas padinae in Ascaris suum intestines.3.The detection of antimicrobial activity of Ascaris suum body fluid and DNA amplification fragment of antimicrobial peptide Cecropin P1 gene indicated Ascaris suum body fluid was directly effective for Staphylococcus aureus,but not for Escherichia coli.The successful amplification of Cecropin P1 from total DNA of Ascaris suum was 660 bp,which belongs to the same evolution branch with published Cecropin P1-P4 of Ascaris suum and the same big evolution branch with insect Cecropin A,and species differences are observed between Cecropins of pigs and those of insects.These results will lay a foundation for the follow-up study on antimicrobial activity of antimicrobial peptide of Ascaris suum.