Monitoring Methods Of Airborne Bacteria In Hospital Environment And The Analysis Of Results

Objective Airborne transmission is the main approach of nosocomial infection. Closelyrelated to the nosocomial infection rate is the air purification of hospital environment,especially the operating theatres and patients concentrated area. Routine monitoring ofhospital air is the key to reduce the incidence of hospital infection. But it’s quitenecessary to do a bacteria culture if using traditional airborne bacterial detection method,which will take2-3days and delay in results. Laser-induced fluorescence spectroscopywas first used to detect airborne biological particles and non-biological particles in themid of1990s. At early stage of this study, it’s found that the bioaerosol can be detectedby the Fluorescent particle counter produced by this technology. Fluorescent particlecounter, Andersen Sampler and natural precipitation method were used to detectairborne bacteria which was sampled under various hospital environment. By analyzingthe results, the practical value of the three method can be compared in this project.Methods (1)The air sampling was done under various hospital environment such asMicrobiology laboratory, the Blood collection room, ICU, Laminar flow operating roomAnhui Provincial Hospital located in Hefei.(2)The number of biological particles wasdynamically monitored by the Fluorescent particle counter,while the number of airbornebacteria was detected by the Andersen Sampler and by natural precipitation method.(3)SPSS17.0software was used to calculate the correlation coefficient r between thenumber of biological particles and airborne bacteria. It was also used to calculate thenumber of bacteria colonies after24hr and48hr cultivation from Andersen sampledbacteria.Results (1)There was a significant correlation between the number of biologicalparticles and the number of airborne bacteria(the Andersen Sampler) in Microbiologylaboratory, the blood collection room, ICU and an operating room, and the Pearsoncorrelation were0.865,0.889,0.775,0.766, respectively.(2)There was a significant correlation between the number of biological particles and the number of airbornebacteria in the blood collection room, ICU and an operating room, and the Pearsoncorrelation were0.723,0.736,0.753, respectively.(3)In the blood collection room, thePearson correlation between the number of bacteria and the number of patients is0.864,while the correlation is0.776between the number of biological particles and thenumber of patients.(4) In the blood collection room, the number of airborne bacteriawas below500cfu/m3in non-treatment time and increased in other condition.(5)After24hr and48hr cultivation of the Andersen sampled bacteria, the number of bacteriacolonies is significantly different.(6)The distribution of indoor bacteria and outdoorbacteria is different at microbiological laboratory. The micrococcus accounts the largestnumber of bacteria in indoor environment such as the blood collection room, ICU,operating room. However, the fungi has the maximum number in the outdoor.(7)Afterultraviolet disinfection, the number of bacteria decreased, and there is a significantdifference between the total number of bacteria.(8)The number of biological particlesand bacteria is related to the operation process in operating room.Conclusions (1) The number of biological particles detected by Fluorescent particlecounter can be used to Calculate the number of airborne bacteria, hopefully, thedynamic monitoring of airborne bacteria can be achieved.(2)The number ofbiological particles and bacteria varies with the amount of patients in the bloodcollecting room. Therefore, it’s suggested to do dynamic disinfection to reduce thepathogen transmission.(3)Activities in operation and cleaning after operation will resultin increasing number of bacteria. Unnecessary operations and staff movement should beminimized to reduce the bacteria in operation room.(4)The optimal culture time ofbacteria collected by Andersen sampler was48h.