Detection Of Airborne Endotoxin And Bioaerosol In Rabbitries

Concentration of airborne endotoxin, bioaerosol including its concentration and composition were measured in rwo different rabbitries. At the same time, the quantitative relationship between the concentrations of airborne endotoxin and airborne gram-negative bacteria as well as airborne endotoxin and airborne aerobic bacteria were analyzed. We can deduce the dangerous to animal and human's health in terms of the distribution of airborne microbiological aerosol particle in ANDERSEN six-stage sampler. Finally, analyzing the concentration of endotoxin and gram-negative bacteria in feedingstuff and feces deduced that the main source of airborne endotoxin and airborne gram-negative bacteria . The study consists of three parts:Part Ⅰ: The concentrations of airborne endotoxin and bioaerosolThe concentrations of airborne aerobic bacteria and airborne gram-negative bacteria were measured by using Andersen-6 sampler for samping and 5% buck blood-blood agar foundation media served as medium. Moreover, the concentration of the airborne gram-negative bacteria and airborne aerobic bacteria were identified with gram-staining and API-array. Airborne endotoxin concentrations were determined using AGI-30 impinger and the Limulus amebocyte lysate (LAL) assay. Air samplers were collected in 50 ml pyrogen-free water. The results indicated that the number of total airborne aerobic bacteria varied from 780 to 20100CFU/m~3, the number of airborne aerobic gram-negative bacteria from 39 to 1030 CFU/m~3. The total amount of airborne endotoxin ranged from 22 to 774 EU/m~3.Moreover, the quantitative relationship between the concentrations of airborne endotoxin and airborne gram-negative bacteria as well as airborneendotoxin and airborne aerobic bacteria were analyzed. Significant correlation were found in this two rabbitries between the concentration of airborne endotoxin and airborne gram-negative bacteria(ri=0.71, T2=0.58 and ri=0.78, r2=0.55) as well as between-the concentration of airborne endotoxin and airborne aerobic bacteria(ri=0.71, T2=0.58 and ri=0.78, r2=0.55). However, these correlations were not very strong. So the total number of the airborne gram-negative bacteria and the airborne aerobic bacteria should not be used for the estimation of the concentration of airborne endotoxin. Part II: The concentration and composition of airborne gram-negative bacteria* airborne Staphylococcus and its aerodynamic diameter(Dae50)In this experiment, we measured the concentration and composion of airborne gram-negative bacteria and airborne Staphylococcus. At first, the gram-negative bacteria and Staphylococcus were identified by using the gram-staining; Second, airborne gram-negative bacteria were divided into Enterobacteriaceae and no- ferment bacteria by O-F-array and oxidation enzyme-array, which were identified by API-20E and API-20NE, respectively. Staphylococcus were identified by API-Staph too. The results indicated that about 3.84 ~ 13.28% of the total number airborne aerobic bacteria were identified as airborne gram-negative bacteria. The main airborne aerobic gram-negative bacteria family included the Enterobacteriaceae, the Nesseria, the Pasteurella, the Pseudomonas and the Acinetobacter. Within the family of the airborne aerobic gram-negative bacteria the species Enterobacteriaceae was predominant and we have not detected the obligate anaerobic airborne gram-negative bacteria in this experiment. About 44.1~ 54. 4% of the total number airborne aerobic bacteria were identified as airborne Staphylococcus, The composition of airborne staphylococcus are staphylococcus aureus > staphylococcus saprophyticus ^ staphylococcus epidermidis^ staphylococcus cohnii and staphylococcus capitis. Among of them, the content of staphylococcus aureus is about 26.3~29.6% of the totalnumber of staphylococcus, Staphylococcus saprophyticus and Staphylococcus epidermidis are the next in order.In addition, the distribution of airborne aerobic bacteria > airborne gram-negative bacteria and airborne staphylococcus aureus on the single stage of the Andersen sampler were analyzed, it concluded that about 56.4% airborne aerobic bacteria^ 44.9% airborne gram-negative bacteria and 49% staphylococcus aureus distributed at 3 and 6 stage with aerodynamic diameters ranged from 0.2jAm to 6fxm which can reach trachea and bronchia even bronchiole, make severe threatening for stockmen and animals' respiratory tract.Part III: The analysis on the resources of airborne endotoxin and airborne aerobic gram-negative bacteria in two rabbitriesThe concentration of airborne endotoxin, airborne gram-negative bacteria and airborne aerobic bacteria were detected in the air outside the two rabbitries. The concentration of endotoxin, gram-negative bacteria and aerobic bacteria were detected in feedingstuff and feces too. Then, we anlysised the quantitive relationship between the airborne endotoxin, the airborne aerobic gram-negative bactria and that in feedingstuff or feces. The concentration of airborne endotoxin -. airborne gram-negative bacteria and airborne aerobic bacteria were 0-154 EU/ m3^ 87-970 CFU/m3 and 0.79-8.30X103CFU/m3 respectively in the air at the distance of 5m outside of the two rabbitres. we have not detected the obligate anaerobic airborne gram-negative bacteria in this experiment. The concentration of endotoxin reached 0.32 — 12.4xlO3EU/g > 0.32 - 14.4 X 104EU/g, gram-negative bacteria reached 0.46-8.70 xlO4CFU/g> 0.78-15.6X 105CFU/g, aerobic bacteria reached 1.14-42.0xl05CFU/g. 1.21-25.3 X107CFU/g respectively in feedingstuff and feces in two rabbitries. So we can see from the results that feedingstuff and feces are the main source of airborne endotoxin and airborne gram-negative bacteria in two rabbitries.The correlation and regression analysis on the concentration of the airborne endotoxin and the airborne aerobic gram- negative bacteria that in the feces and the feed were carried out. Analysis indicated the airborne endotoxin in the rabbit house were positive relative with the concentration of the endotoxin in feces and the feed (ri=0.64, i2=0.47 and ri=0.58? T2=0.74). The same results were analysed between the concentration of airborne aerobic gram-negative bacteria and the concentration of gram-negative bacteria in feces and the feed (ri=0.71, r2=0.87 and ri=0.42, r2=0.78) . These results indicated the feces and the feed were the most important resources for the airborne endotoxin and airborne aerobic gram-negative bacteria in two rabbitries.