Evaluation Of The Efficacy Of Disinfectants And Research On Resistance To Disinfectant Of Bacteria From Pig Farms

Disinfection is the most important,efficient and economical measure to prevent and control infectious diseases.The wide application of disinfectants has played a huge role in improving the farm benefits,preventing and controlling diseases.However,the large used of disinfectant has made drug resistance of bacteria and the declined of disinfection effectiveness,bacteria have become resistant to it,and the disinfection effect has declined.At present,Reports in this area are rare,which makes farmer confused when disinfect their farms.So,The research on the sensitivity of farm bacteria has great significance for the selection of high-efficiency disinfectants,improvement of disinfection effect and the prevention and control of diseases.The researcher investigated the bacterial contamination and resistance of disinfectants by 300 samples of pig anus and 100 samples of skin swab in 5large-scale pig farms in Guizhou provincein,in the period,E.coli,salmonella,Enterococcus and Staphylococcus aureus were isolated and identified according to national and local standards.The microbial dilution method was used to determine the Minimum Inhibitory Concentration?MIC?of the isolated bacteria to Sodium Dichloroisocyanurate,Povidone,Glutaraldehyde,Sodium hydroxide,Peroxyacetic acid,Compound phenol,Benzalkonium Bromide,Glutaral and Halimide Solution.The phenol coefficient method was used to determine the disinfection effect of these nine disinfectants to evaluate the disinfection effect of the commonly used disinfectants in pig farms;Detection of resistance gene of QACs resistance gens by PCR.result:?1?The disinfectants commonly used in five farms are mainly halogen?Sodium Dichloroisocyanurate,Povidone?,Glutaraldehyde,Oxidant?Peroxyacetic acid?,Alkali?Sodium hydroxide?,phenol?Compound phenol?,Quaternary ammonium salts?Benzalkonium Bromide,Glutaral and Halimide Solution?.?2?Nine commonly used disinfectants have the same killing activity against the standard strains of E.coli?ATCC25922?and Staphylococcus aureus?ATCC25923?at the recommended concentration.The MIC values are Sodium Dichloroisocyanurate2048mg/L,Povidone 1024mg/L,Glutaraldehyde 512mg/L,Sodium hydroxide1024mg/L,Peroxyacetic acid 512mg/L,Compound phenol 16mg/L,Benzalkonium Bromide 4mg/L,Glutaral and Deciquam Solution 8mg/L,Halimide Solution 32mg/L.Evaluation of sterilization efficacy of 9 kinds of disinfectants using phenol coefficient determination method on standard strain of Staphylococcus aureus?ATCC6538?and the results show that different disinfectants have certain differences in the bactericidal efficacy of bacteria,and the disinfection effect of quaternary ammonium disinfectants is the best.The phenol coefficients are arranged in order from largest to smallest:Glutaral and Deciquam Solution,Benzalkonium Bromide,Glutaral and Deciquam Solution,Compound phenol,Sodium hydroxide,Peroxyacetic acid,Glutaraldehyde,Povidone,Sodium Dichloroisocyanurate.Priority is given to the use of quaternary ammonium disinfectants.?3?The MIC values of E.coli,salmonella,Enterococcus and Staphylococcus aureus isolated from the pig farms to Nine kinds of disinfectants show that the MIC of Compound phenol is 128mg/L,MIC₉₀value is 8 times higher than standard strains;The MIC of Peroxyacetic acid is 2048mg/L,MIC₉₀value is higher than standard Strain 4 times;The MIC of Sodium Dichloroisocyanurate is 4096 mg/L,MIC₉₀value is 2 times higher than the standard strain;The MIC of Povidone MIC 2048 mg/L,MIC₉₀value is 2 times higher than the standard strain;The MIC of Glutaraldehyde is1024 mg/L,MIC₉₀value Benzalkonium Bromide is 2 times higher than the standard strain 8mg/L,MIC₉₀value is 2 times higher than the standard strain;The MIC of Glutaral and Deciquam Solution is 16 mg/L,MIC₉₀value is 2 times higher than the standard strain;The MIC of Halimide Solution is 64mg/L,MIC₉₀2 times higher than the standard strain;The MIC of Sodium hydroxide is 1024mg/L,MIC₉₀value is the same as the standard strain.It shows that the isolated strains except Sodium hydroxide show a certain degree of resistance to common disinfectants.?4?Nine QACs resistance gens were detected in isolates,include qac E?1?qac A/B?qac E?qac F?qac G?qac H?sug E?c??sug E?p??mec A,the detection rate of sug E?c?gene is the highest in E.coli,Salmonella,and Enterococcus was the highest,which are 87.23%,93.55%,and 88.16%.The highest detection rate of qac F in Staphylococcus aureus is 67.44%,which the drug resistance gene spectrum is the broadest.The qac A/B gene was only detected in Staphylococcus aureus,the detection rate was 6.98%.The qac E?1,qac E,qac F,sug E?c?,sug E?p?genes are generally prevalent in four bacteria.Conclusion:The 9 commonly used disinfectants have a bactericidal effect within the recommended range of use,and have a good killing effect on standard strains,but the 4 pig farms isolates show 2-8 times Resistance except Sodium hydroxide.The investigated farms recommend to use sodium hydroxide and Sodium Dichloroisocyanurate,use Peroxyacetic acid with caution,and compound phenol preparations is not recommend in most farms.Disinfectant resistance genes are generally prevalent in E.coli,Salmonella,Enterococcus,and Staphylococcus aureus in pig farms,should cause the attention.