Detection Of Airborne Endotoxin And Microbiological Aerosol In Sickroom Environment

In this study, we measured the concentrations of airborne endotoxin and bioaerosol including the composition of bioaerosol in two different sickrooms. at the same time compared the quantitative relation between the concentration of airborne endotoxin and the concentration of airborne gram-negative bacteria as well as airborne aerobic bacteria; we also speculated the danger to the health of human in terms of the distribution of airborne microbiological aerosol particle in ANDERSEN six-stage sampler. Finally, analyzing the concentrations of airborne endotoxin and airborne gram-negative bacteria in the hallway we speculated the source of airborne endotoxin and airborne gram-negative bacteria.The study consists of three parts:PartⅠ:The concentrations of airborne endotoxin and microbiological aerosolThe concentrations of airborne aerobic bacteria and airborne gram-negative bacteria were measured by using Andersen-6 sampler to sample and 5% buck blood-blood agar foundation media served as medium. Meanwhile, the concentrations of them were identified with gram-staining and API-assay. The concentration of airborne endotoxin was measured by using the AGI-30 impinger and LAL-assay, the AGI-30 impinger filled with 50ml pyrogen-free water. The result indicted that the concentration of the airborne endotoxin was 33—267EU/m~3, the concentrations of airborne aerobic bacteria and airborne gram-negative bacteria were 603～758CFU/m~3 and15—46CFU/m~3 . Analyzing the quantitative relation between the concentration of airborne endotoxin and the concentration of airborne gram-negative bacteria as well as airborne aerobic bacteria, there were no significant correlation between the airborne endotoxin and that of the airborne gram-negative bacteria as well as the airborne aerobic bacteria. They were r1=0.32 r2=0.27 and r1=0.23 r2=0.24 .That is to say, it was of little reliability to reckon the the concentration of the endotoxin on the concentration of airborne gram-negative bacteria or airborne aerobic bacteria.PartⅡ:Analyzing the concentration and composition of the airborne aerobic gram-negative bacteria including its aerodynamic diameterIn this experiment, we measured the concentration and composition of airborne gram-negative bacteria. At first, the gram-negative bacteria were identified by using the gram-staining; Second, the airborne gram-negative bacteria were divided into Enterobacteriaceae and no- ferment bacteria by O-F-assay and oxidation enzyme-assay, which were identified by API-20E and api-20NE respectively. Result indicated that the concentration of airborne aerobic gram-negative bacteria was about2.18-4.88% consisting of Enterobacteriaceae ,Pseudomonas ,Pasteurella and Neisseria .Among them Enterobacteriaceae was dominant, but we have not detected the obligate anaerobic gram-negative bacteria in this experiment.Analyzing the distributions of the airborne gram-negative bacteria and airborne aerobic bacteria in ANDERSEN six-stage sampler, we can see that 52.6% of the airborne aerobic bacteria and 41.9% of the gram-negative bacteria stay at 3-6 stage, meanwhile their aerodynamic diameter are 3-0.2um. These particles can enter the human, s windpipe bronchus and thin bronchus, They are very dangerous to human.PartⅢ:The analysis on the sources of the airborne endotoxin and the airborne aerobic gram-negative bacteria in sickrooms In this experiement, we detected the concentration of the airborne endotoxin,the airborne aerobic gram-negative bacteria and airborne aerobic bacteria in the hallway of the sickroom. Then we analyzed the quantitative relation between the airborne endotoxin ,the airborne aerobic gram-negative bactria and those in the hallway . The concentrations of endotoxin, gram-negative bacteria and aerobic bacteria were large, They reached 66-512EU/m~3 , 32-63CFU/m~3 and 910.60—1270.49CFU/m~3, We have not detected the obligated anaerobic gram-negative bacteria. These results showed that the sources of airborne endotoxin and the airborne gram-negative bacteria probably come from the hallway of the sickroom.Analyzing the quantitative correlation between the concentrations of the airborne endotoxin in the two sickrooms and the concentrations of airborne endotoxin in the two hallways. At the same time,we did the same work to airborne gram-negative bacteria. Analysis indicated that the airborne endotoxin and the airborne aerobic gram-negative bacteria in the sickroom were positive relative to the concentrations of the endotoxin and gram-negative bacteria in the hallway(r=0.38,r= 0.64and r=0.41,r=0.72). The two regression equations were significant. These results indicated that the hallway environment was one of the important sources for the airborne endotoxin and airborne aerobic gram-negative bacteria...