Effectiveness of chemical inactivation of infectious liquid biological waste: A randomized sample study of research laboratories in Switzerland

Laboratory wastewater has been suggested as an important escape route for microorganisms from research environments. Likely reasons for the unintentional release of laboratory organisms are shortcomings in the handling of infectious liquid biological waste (LBW) and inadequate inactivation procedures. We developed an analytical approach to investigate the use of chemical inactivation (CI) procedures in Swiss research laboratories by on-site random sampling of presumably inactivated infectious LBW and testing it for the presence of infectious lentiviruses (HIV-1) and adenoviruses (AdV). In addition, standard operating procedures (SOPs) for CI were collected and evaluated, and laboratory-staff knowledge of CI processes was assessed using a questionnaire. Although we found several deficiencies in the technical knowledge and training of laboratory staff on the CI of LBW, as documented by 27 returned questionnaires, no infectious viruses were detected in the eight LBW samples collected. Whilst we acknowledge that the number of LBW samples and SOPs is small, we conclude that CI of LBW containing infectious lentiviruses and adenoviruses does not result in the systematic release of considerable amounts of infectious viruses into the environment from research laboratories in Switzerland.