Laboratory safety: handling B. pseudomallei isolates without a biosafety cabinet

Abstract

Background: B. pseudomallei is a tier 1 select agent that is associated with laboratory-acquired melioidosis, with international guidelines recommending isolate handling within a class II biosafety cabinet (BSC) in a Biosafety Level (BSL) 3 facility. In low-resource settings this may not be practical, and therefore the authors aimed to assess the risk of laboratory-acquired melioidosis during routine work. Methods: A questionnaire combined with two serological assays were conducted to determine prior exposure to the organism. Additionally, we performed controlled environmental air sampling during 78 laboratory handling events including plate opening, oxidase testing, and McFarland suspension creation. Results: Of 30 laboratory scientists to handle B. pseudomallei on 1,267 occasions outside a biosafety cabinet no infections were documented and all participants remained seronegative. None of the experiments demonstrated aerosolisation of the organism. Conclusion: This study suggests the risk of laboratory-acquired melioidosis is likely to be low. However, individual laboratories will need to undertake a risk assessment including melioidosis endemicity, availability of resources for containment, the nature of routine handling to be undertaken, and the presence of predisposing risk factors for infection in the staff concerned. Further research is required to better understand on the risk of infection in the microbiology laboratory. Contribution: IG conceived of the idea, obtained funding, obtained ethics approval, performed bioaerosol experiments and contributed to each section of the manuscript. Publication statement: This research has been published in the Journal of Clinical Microbiology.