Autoclaving Contaminated Liquids: No Problem?

In many research and diagnostic facilities, liters of biologically contaminated liquid waste are produced on a daily basis and need to be safely disposed of. The gold standard is steam sterilization, namely, in most cases autoclaving for 20 minutes at 121°C. Here we demonstrate the importance of the following parameters when autoclaving liquid waste solutions in a laboratory setting: (1) size of the receptacle for the reference probe, (2) material of the vessel containing the liquid to be autoclaved, and (3) volume of the liquid in the receptacle. If not appropriately controlled, the temperature required to inactivate the liquid might never be reached at all, thus representing a biohazard that should not be underestimated. Our results demonstrate that it is critical to use identical receptacles and liquid volumes for the temperature reference probe and for the liquid to be autoclaved

Bacillus anthracis as a cause of bovine abortion - a necropsy case requiring special biosafety measures.

INTRODUCTION In spring 2017, the first case of bovine anthrax in 20 years in Switzerland occurred in the canton of Jura. Carcasses of anthrax-deceased animals should not be opened due to the formation of highly resistant spores bearing the risk of environmental contamination and aerosolization. Nevertheless, in the course of this local outbreak, one sick cow from the affected farm, whose blood repeatedly tested negative for Bacillus anthracis, was necropsied after euthanasia under special biosafety precautions at the Institute of Animal Pathology, Vetsuisse-Faculty Bern. Necropsy revealed ventral edema, fetal death, necro-hemorrhagic placentitis and necrotizing iliac lymphadenitis. Bacillus anthracis was isolated only from placenta and altered lymph node. The biosafety measures taken during and after necropsy prevented a contamination of the necropsy environment, which was proven with bacteriological swabs. This case shows that anthrax may elicit unspecific symptoms mimicking other diseases, and veterinarians must be aware of these non-septicemic cases

Rapid reconstruction of SARS-CoV-2 using a synthetic genomics platform.

Reverse genetics has been an indispensable tool to gain insights into viral pathogenesis and vaccine development. The genomes of large RNA viruses, such as those from coronaviruses, are cumbersome to clone and manipulate in Escherichia coli owing to the size and occasional instability of the genome1-3. Therefore, an alternative rapid and robust reverse-genetics platform for RNA viruses would benefit the research community. Here we show the full functionality of a yeast-based synthetic genomics platform to genetically reconstruct diverse RNA viruses, including members of the Coronaviridae, Flaviviridae and Pneumoviridae families. Viral subgenomic fragments were generated using viral isolates, cloned viral DNA, clinical samples or synthetic DNA, and these fragments were then reassembled in one step in Saccharomyces cerevisiae using transformation-associated recombination cloning to maintain the genome as a yeast artificial chromosome. T7 RNA polymerase was then used to generate infectious RNA to rescue viable virus. Using this platform, we were able to engineer and generate chemically synthesized clones of the virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)4, which has caused the recent pandemic of coronavirus disease (COVID-19), in only a week after receipt of the synthetic DNA fragments. The technical advance that we describe here facilitates rapid responses to emerging viruses as it enables the real-time generation and functional characterization of evolving RNA virus variants during an outbreak