Laboratory Safety: Handling Burkholderia pseudomallei Isolates without a Biosafety Cabinet

Burkholderia 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 3 (BSL3) facility. In low-resource settings, this may not be practical; therefore, we aimed to assess the risk of laboratory-acquired melioidosis during routine work. Prior exposure to the organism was determined with a questionnaire and concomitant serology. Of 30 laboratory scientists handling B. pseudomallei on 1,267 occasions outside a biosafety cabinet, no infections were documented and all participants remained seronegative. Additionally, we performed controlled environmental air sampling during 78 laboratory handling events, including plate opening, oxidase testing, and McFarland suspension creation. None of the experiments demonstrated aerosolization of the organism. This study suggests the risk of laboratory-acquired melioidosis is 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. Additionally, laboratories should take region-specific guidelines into consideration. Further research is required to better inform on the overall risk of infection in the microbiology laboratory.