Assessment of Bioaerosol Concentrations in Laboratory Animal Rooms and Its Associated Environmental Factors

Abstract

Objective Bioaerosol is defined as the suspension of airborne particles from microbe, animal and plant in the ambient air, which causes potential health problems. There are several health risk factors in laboratory animal rooms such as bioaerosol or animal allergens originated from animal fur, feces, urine, food, or bedding. Bioaerosol in laboratory animal rooms may cause respiratory symptoms such as asthma and infectious diseases to workers or researchers. In spite of the potential harms in working individuals in the rooms, assessment of bioaerosol concentrations in the laboratory animal rooms has been lacking. The purposes of the study were to assess temporal changes of bioaerosol concentrations in a laboratory mouse room (LMR) and in a laboratory rabbit room (LRR) and to determine environmental factors associated with total bacteria and total fungi concentrations.

Methods The concentrations of airborne total bacteria, total fungi, endotoxin, and (1→3)-β-D-glucan were sampled once a month from March 2011 to February 2012 in the LMR and LRR. Andersen one-stage sampler was used to collect total bacteria and total fungi for five minutes, three times a day. Endotoxin was collected using 3-piece cassettes with a glass fiber filter for six hours and was analyzed by the kinetic-turbidimetric Limulus Amebocyte Lysate (LAL) assay. (1→3)-β-D-glucan was performed using two stage cyclone bioaerosol sampler for six hours and assayed using the kinetic chromogenic LAL assay. During the total bacteria and total fungi sampling, environmental factors such as temperature, relative humidity (RH), CO2 and illuminance were measured using the real time monitors.

Results The total bacteria concentrations in the LMR showed a gradual increase during the summer, while the highest concentration in the LRR was seen in July and November. The total fungi concentrations showed a similar seasonal change pattern in the LMR and LRR with noticeable increases in summer. The endotoxin concentrations did not show large variations, but the concentrations slightly increased in winter for the both rooms. The (1→3)-β-D-glucan concentrations seemed to increase from warmer spring to summer in the LMR and LRR. RH was the most influential environmental factors on concentrations of the total bacteria and total fungi. Temperature, CO2 and illuminance were also slightly associated with total bacteria and total fungi concentrations. The overall bioaerosol concentrations were significantly greater in the LRR than in the LMR.

Conclusion The concentrations of bioaerosol in the LMR and LRR varied greatly depending on seasonality, and their changes were affected by the environmental factors. Therefore, bioaerosol concentrations should be controlled by periodic monitoring, and potential health problems should be considered for working individuals in laboratory animal rooms.