| The microbial concentration and composition in the air are the main causes of air pollution,especially the presence of some pathogenic microorganisms,which has increased the incidence risk of animals and humans.The Macropus of Australian field in Nanjing Hongshan Forest Zoo are popular with many tourists all the time.Unfortunately,the Macropus suffered from bacterial diseases frequently in recent years,especially the alveolar infection and its secondary disease which had caused serious damage to the feeding and breeding of Macropus.In this situation,it is particularly important to understand the concentration and the distribution of airborne aerobic bacteria in Macropus houses,and the same is true for the targeted environmental sanitation control.The prevention and treatment of bacterial diseases in the Zoo mainly lies on the use of chemical disinfectants and antibiotics.Analyzing the composition of common pathogens in the Macropus house and observing the antibiotic sensitivity of pathogens can provide guidance for the daily control and the use of antibiotic.In order to ensure the effectiveness of daily disinfection work and provide a cleaner and safer living environment for the Macropus,it is extremely necessary to evaluate these commonly used disinfectants in Macropus house and then screen out several disinfectants with strong disinfection capability for daily use.This study through the above research is to provide a theoretical basis for strengthening the prevention and control of bacterial diseases in Macropus.The specific contents of the trial are as follows:1 Preliminary Study on Airborne Aerobic Bacteria in Macropus HouseIn this study,the colony natural sedimentation method was used to measure the concentration of airborne aerobic bacteria in five areas including playground,buffer area,macropus room,pavement and feed warehouse.16S rRNA and biochemical identification methods were used to analyze the proportion of airborne aerobic bacteria.The isolates were used to inoculate mice to observe their pathogenicity.The drug resistance test paper method was used to analyze the drug resistance of pathogenic bacteria.The results showed that in different areas,the concentration of airborne aerobic bacteria in the macropus room and feed warehouse were significantly higher than that in other areas.In different seasons,the concentration of airborne aerobic bacteria in the feed warehouse was the highest in autumn,while the other areas were the highest in summer.All areas were the lowest in winter.The summer data of the macropus giganteus house was lacking,and the highest concentration of airborne aerobic bacteria in the macropus giganteus house and the feed warehouse was the autumn.In the 71 strains isolated from the macropus house,Staphylococcus bacteria was the most,a total of 37 strains,accounting for 52.1%of the isolates,among which Staphylococcus equorum was the dominant bacteria.There were a total of 31 strains,accounting for about 43.7%of the isolates,among which Escherichia coli was the predominant strain.There were only 3 isolates of Streptococcus were isolated,accounting for about 4.2%of the isolates.In this study,6 strains of pathogenic bacteria were screened,including 2 strains of Escherichia coli,1 strains of Shigella flexneri,2 strains of Staphylococcus aureus and 1 strains of Streptococcus lutetiensis.The results of drug sensitivity test showed that all the pathogenic bacteria were resistant to clindamycin and sensitive to ciprofloxacin,florfenicol,gentamicin,enrofloxacin and sulfamethoxazole.In addition,different strains have different degrees of resistance to other drugs.2 Screening of common disinfectant in Macropus houseUsing broth dilution method to test the minimum inhibitory concentration(MIC)and the minimum bactericidal concentration(MBC)of 9 kinds of disinfectant toward 2 standard strains(Escherichia coli 8099,Staphylococcus aureus ATCC6538)and isolates from the Macropus house(8 strains of Escherichia coli and 5 strains of Staphylococcus aureus),using suspension quantitation bactericidal trail to test the disinfective effectiveness of 9 kinds of disinfectant which are under their preventive concentration toward the 2 kinds of standard strains.According to the trail above,the disinfectants with strong bacteriostasis and disinfection capacity could be screened out,and then we could make a comprehensive evaluation to the disinfective effect combined the result of field disinfection test.The results showed that 4 of the 9 kinds of disinfectant have the bacteriostasis and disinfection capacity at relatively low concentrations,they are Glutaral and Deciquam,Dilute Glutaral Solution,Halimide Solution and Peracetic Acid Solution.The MIC of them were 97.66 mg/L,155.04 mg/L,0.009%and 0.031%,respectively.The MBC of them were 97.66mg/L,307.69 mg/L,0.018%and 0.062%,respectively.Under the recommended concentration,Peracetic Acid Solution and Dilute Glutaral Solution could kill 2 kinds of test bacteria in 5 min;Halimide Solution could kill Escherichia coli in 5 min and kill Staphylococcus aureus in 10 min;Glutaral and Deciquam could kill Escherichia coli in 10 min and there was no significant difference between the killing logarithm of Glutaral and Deciquam and positive control group toward Staphylococcus aureus in 15 min;the difference between the killing logarithm of 84 Disinfectant Solution and positive control group toward the 2 kinds of test bacteria in 15 min were not significant.These disinfectants above had good sterilizing effect.Using analysis by synthesis of 9 kinds of disinfectant MIC,MBC and disinfective effectiveness,we could screen out 4 kinds of disinfectant with strong bacteriostasis and disinfection capability,such as Halimide Solution,Glutaral and Deciquam,Peracetic Acid Solution and Dilute Glutaral Solution.When they were carried out to the field disinfection test for 30 min,the disinfecting rate of Peracetic Acid Solution and Halimide Solution toward airborne bacteria were both more than 90%,the specific value were 92.9%and 90.6%,respectively.The rate of Glutaral and Deciquam was 88.4%.In contrast,the lowest disinfecting rate was belonged to Dilute Glutaral Solution,it was only 80.3%.In general,the high concentration of airborne aerobic bacteria was showed in the macropus room and feed warehouse when they were in summer and autumn,and the attention should be fixed on macropus giganteus room because of its worst performance in health status.According to the results,there were pathogenic bacteria in the macropus room,so the prevention and control measures should be carried on.In addition,the clindamycin which was commonly used in the macropus giganteus house should be abandoned,because this kind of antibiotic no longer has any effect.The sterilization effects of Halimide Solution,Peracetic Acid Solution and Glutaral and Deciquam among the 9 kinds of commonly used disinfectant were excellent,so them were recommended for daily use. |
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