| In recent years,the problem of bacterial diseases in pig farms has become more and more prominent,due to the unreasonable drug use and the management is not standard,part of the pig farm broad-spectrum drugs bacterial disease prevention and control,make the bacteria resistant strains increase,resistance is more and more complex,not only to farm environment pollution,also the clinical medication of bacterial disease prevention and treatment of difficult,At the same time,it restricts the healthy development of pig industry and affects public health safety.This study first of Guiyang huaxi district five large-scale pig farms mainly epidemic investigation analysis,secondly the pig sewage separation identification,pathogenic bacteria and drug resistance analysis of the main isolated bacteria,finally,the pig pig bacteria content changes before and after disinfection environment analysis,in order to farm the bacterial disease prevention and control to provide certain reference basis.1.Investigation of main epidemics in pig farms in Huaxi DistrictThrough field visits and access to archives of 5 large-scale pig farms randomly selected from Huaxi District of Guiyang during the four years from 2017 to 2020,an investigation was conducted on pig breeding,common epidemic diseases and drug prevention and control of bacterial diseases in pig farms.The results showed as follows:In terms of pig breeding,the overall pig production in Huaxi District showed a downward trend from 2017 to 2020,with the production decreasing from 108,400 in 2017 to 33,900 in 2020,with a decline rate of68.73%.There were bacterial disease,helminosis and viral disease in pig farms,of which the average incidence of bacterial disease was 9.21%(1 660/18 029),helminosis was 5.38%(970/18 029),and viral disease was 3.50%(632/18 029).The highest rate of mixed bacterial and helminosis was 4.2%(757/18 029).The results showed that the most common blight of pig farm was bacterial disease,followed by helminosis and virus disease.According to the investigation of drug prevention and control,the use of drug prevention and treatment as the main measures,the most commonly used prevention and control drugs in farms areβ-lactam,sulfonamides and flufenicol and other antimicrobial drugs.2.Isolation and identification of main bacteria in sewage from pig farms in Huaxi DistrictSamples of effluent from 5 large-scale pig farms in Huaxi District were collected,and bacterial counting method,isolation and culture method,biochemical identification,PCR identification and pathogenicity test were adopted.The results showed that:The bacterial content in sewage water of 5 large-scale pig farms in Huaxi District was 2.4×10~5CFU/L～5.8×10~5 CFU/L,which all exceeded the national standard(GB4789.2-2010).The bacteria in sewage water were isolated and cultured for colony morphology observation,Gram staining microscopic examination,biochemical identification and PCR identification.Four dominant bacteria were isolated and identified,respectively named HX-1-4,among which(1)HX-1 strain was round,smooth,with neat edges,wet and slightly raisedαhemolysis,with medium size colony.Gram-positive cocci were found in grape clusters by Gram staining microscopy.(2)HX-2 strain was round,smooth,moist,and with neat edges,with medium size colony.Microscopic examination by Gram staining showed double arrangement of Gram-negative bacilli.(3)HX-3 strain was round,smooth,moist,with neat edges,slightly raised,and grayish white medium size.By Gram staining microscopic examination,HX-3 strain was Gram-negative and presented single and double array of Bacillus trilobus.(4)HX-4 strain was round,smooth,moist,with neat edges,slightly raised and grayish white medium size colony.After Gram staining,HX-4 strain was gram-positive bacillus with single and double arrangement.In the pathogenicity test,Staphylococcus haemolyticus had the strongest pathogenicity,followed by Escherichia coli,Acinetobacter was the weakest and Lysinobacter was not pathogenic.3.Drug sensitivity test of main pathogenic bacteria in pig farm effluent in Huaxi DistrictFour dominant bacteria were randomly selected and identified by paper diffusion method,among which 25 strains of Staphylococcus haemolyticus,16 strains of Acinetobacter,20strains of Escherichia coli and 10 strains of Lysinobacter were tested for drug sensitivity.The results showed that:(1)The susceptibility rates of Staphylococcus hemolyticus to cefradine,gentamicin and erythromycin were 76%(19/25),72%(18/25)and 68%(17/25),respectively.The susceptibility rates to butamicarina and cefoperazone were 20%(5/25)and 16%(4/25),respectively.The resistance rates were 68%(17/25),64%(16/25)and 60%(15/25),respectively,and the lowest resistance rates were 20%(5/25)to gentamicin and cefradine.(2)The sensitivity rates of Acinetobacter to butamicana,tetracycline and erythromycin were 75%(12/16),68.75%(11/16)and 68.75%(11/16),respectively.The rates of moderate sensitivity to cefradine,gentamicin and cefazoline were 37.5%(6/16),31.25(5/16)and 31.25(5/16),respectively.The rates of resistance to phenoxacillin were 62.5%(10/16),respectively.The lowest drug resistance rate was 18.75%(3/16)to butamikana.(3)The susceptibility rates of Escherichia coli to gentamicin,ampicillin and minocycline were 75%(15/20),75%(15/20)and 70%(14/20),respectively.The susceptibility rates to butamicarina,erythromycin and cefotaxidine were 40%(8/16),30(6/16)and 30(6/16),respectively.They showed strong resistance to penicillin,with a resistance rate of 65%(13/20),and the lowest resistance rate to gentamicin and piperacillin was 15%(3/20).(4)The susceptibility rates of lysinobacter to minocycline,erythromycin and butamicarb were 70%(7/10),70%(7/10)and 70%(7/10),respectively.The susceptibility rates of lysinobacter to neomycin,ceftriaxone and cefoperazone were 50%(5/10),50%(5/10)and 50%(5/10),respectively.The resistance rate to cefotaxidine was 60%(6/10),and the lowest resistance rate to minocycline was 10%(1/10).According to the results of drug sensitivity test,it can provide some suggestions for rational drug use of bacterial diseases in pig farms.4.The influence of environmental disinfection on the bacterial content of pig farmThe bacteriological content of three large scale pig farms was detected by plate counting method.The results showed that the bacteriological content of three large scale pig farms was determined by using disinfectant(sodium dichloroisocyanate)and disinfectant(iodine-phosphate compound solution).The results showed:(1)in the air before and after disinfection The mean amount of bacteria in field A decreased from 9.66×10~4CFU/m~3 to 6.17×10~3CFU/m~3;the mean amount of bacteria in field B decreased from 9.48×10~4CFU/m~3 to 5.73×10~3CFU/m~3;and the mean amount of bacteria in field C decreased from 9.68×10~4CFU/m~3 to6.97×10~3CFU/m~3.(2)in the feces before and after disinfection The mean bacteria content in field A decreased from 166.06×10~4CFU/g to 9.73×10~4CFU/g,the mean bacteria content in field B decreased from 165.58×10~4CFU/g to 9.67×10~4CFU/g,and the mean bacteria content in field C decreased from 165.83×10~4CFU/g to 9.86×10~4CFU/g;(3)in the sewage before and after disinfection The mean bacteria content in field A decreased from 27.92×10~4CFU/L to 3.9×10~4CFU/L,the mean bacteria content in field B decreased from 27.46×10~4CFU/L to3.82×10~4CFU/L,and the mean bacteria content in field C decreased from 27.75×10~4CFU/L to4.09×10~4CFU/L.The results showed that the use of disinfectant could effectively reduce the bacterial content in pig farm.In conclusion,the main daily epidemics of 5 large-scale pig farms in Huaxi District of Guiyang City were bacterial disease,followed by helminosis and virus disease.Antimicrobial drugs were mainlyβ-lactam,sulfonamides and flufenicol,etc.Staphylococcus haemolyticus showed the highest pathogenicity,followed by Escherichia coli,Acinetobacter showed the lowest pathogenicity,and Lysinobacter showed no pathogenicity.Drug sensitive test showed that hemolytic staphylococci of cephalosporins,erythromycin and gentamicin drug sensitive,acinetobacter,d amine card that,tetracycline and erythromycin and other sensitive,e.coli to gentamicin,ampicillin and minocycline drugs such as sensitive,lysine bacillus of minocycline,erythromycin and butylamine card that drugs such as sensitive;Disinfectants were used to disinfect the environment of pig farms,and the content of bacteria in air,feces and sewage water was significantly reduced before and after disinfection.These results provide scientific basis for the prevention and control of bacterial diseases in pig farms. |
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