Hazardous biological agents and the occupational exposure risks thereof in an animal testing facility

Abstract

Animal testing facilities play a vital role in the world of biomedical research. However, the presence of hazardous biological agents (HBAs) introduces potential health risks for personnel involved. This risk arises from possible exposure to HBAs through inhalation of urinary proteins and faecal matter from the animal's bedding, animal dander or accidental animal bites and scratches. Exposure to HBAs could lead to a variety of negative health effects that include inflammatory responses, respiratory diseases, digestive tract infections and general discomfort. This study aimed to determine the presence and identify potential HBAs in an animal testing facility. Active and passive biological sampling were performed using both culture-dependent methods, such as active air sampling on agar plates, settle plates, surface swabs, and contact plates and culture-independent methods, including the bioaerosol cyclone, a size-selective sampler. Metabarcoding was carried out using nanopore sequencing to identify potential HBAs present in the facility at both the genus and species levels. Furthermore, physical parameters were measured to assess their influence on the abundance of microbial growth, while chemical parameters (dust particulate matter) were measured to evaluate their role as carriers and the potential risk of HBA inhalation. A total of 62 HBAs were identified in the facility, five of which are toxin-producing, and 53 classified as bacterial risk group 2 agents according to the Regulations for Hazardous Biological Agents, 2022 (South Africa). Six HBAs were identified as fungal risk group 2 agents, and three risk group 3 agents. The highest average concentration of microbial growth was in the cloak room collected by use of the microbial air sampler. The high microbial concentrations in the cloak room indicate that the area, which is supposed to be clean when donning and doffing personal protective equipment (PPE), is actually a hazard area and a source of contamination for the workers in this area and the rest of the facility. There were no statistically significant correlations between the environmental parameters and the microbial growth quantified within the facility. The combination of low air velocity and a high concentration of small dust particles(< 1 µm) suggests that the smallest particles (potentially containing HBAs) remain suspended in the air for extended periods, increasing the risk of inhalation and deep lung penetration. The variety of risk group 2 and 3 HBAs present in the facility and inadequacies of the control measures, such as the PPE and poor ventilation systems, lead to the conclusion that the HBAs found in the animal testing facility pose a potential moderate risk to its workers' health