Applied Biosafety

An outbreak of cryptosporidiosis involving 10 primary cases, as well as several additional presumptive primary cases, occurred among third-year veterinary medical students in October 2011. The investigation revealed that the outbreak was associated with a laboratory exercise involving euthanized dairy calves that were naturally infected with Cryptosporidium parvum, and was exacerbated by inappropriate personal protective equipment (PPE), the unsuitable location of the laboratory, and the absence of appropriate hand hygiene. The lab location was such that students lacked an area where contaminated outer clothing could be removed safely, resulting in the potential for secondary spread. One additional case probably resulted from secondary spread. The institutional biosafety officer and the chair of the college occupational safety committee worked with teaching faculty and the Dean of the College of Veterinary Medicine and other stakeholders to create and implement a series of control measures to minimize the potential for future infections among students. Control measures included prescreening of donor calves and culling of infected animals, changing the location of the laboratory to a facility where suitable hand hygiene and sanitation are accessible, using more robust PPE, removing and laundering of protective clothing on location, and better training for students exposed to potential sources of zoonotic pathogens. Since implementation of these control measures, several cycles of instruction have been completed with no additional infections. This case study illustrates the need for university biosafety professionals to proactively assist academic faculty and students by providing guidance for instructional activities involving possible biohazards.

Until recently, academic institutions and Principal Investigators (PIs) maintained a de-facto immunity from criminal prosecution for worker injuries and deaths attributed to unsafe laboratory practices. This status quo changed in 2011 when a state prosecutor filed felony charges for statutory and regulatory safety violations against the Regents of a state university system and a tenured professor. This unprecedented action was the first time a University Board of Regents and a professor at a university were jointly charged with felony violations associated with laboratory procedures that resulted in the death of a laboratory worker. This article presents sentinel factors associated with the prosecution and settlement of the prosecution, with a discussion of resulting implications for academic institutions/institutes and PIs.

The National Biodefense Analysis and Countermeasures Center (NBACC) conducts research at Animal Biosafety Level 3 (ABSL-3) and ABSL-4. At NBACC, all solid waste in ABSL-3 and ABSL-4 must be sterilized by a validated method before it leaves the containment suites for disposal. Carcass biomass differs across laboratory animal species and its composition differs compared to solid disposable laboratory waste and reusable materials like scrub suits. Successfully sterilizing carcasses requires cycle parameters that differ from those used to sterilize other forms of solid waste and smaller animal species. Surgical placement of the biological indicators (BI) was employed to ensure steam penetrated the carcasses completely. In this article the authors describe a process for validating autoclave cycles using readily available animal carcasses that mimic the biomass of the non-human primate and guinea pig carcasses planned for use in future studies, to accurately develop a cycle that takes into account weight, mass, and muscle depth as well as the moisture content inherent in carcasses. The results demonstrate the extended time duration required for the sterilization phase of the cycle and the effect of increased carcass mass on the ability to validate autoclave cycles.

Room fumigation has traditionally been performed using formaldehyde. However, recently new methods have been developed, including vaporized hydrogen peroxide (VHP). VHP offers a number of advantages, such as degradation into non-toxic compounds (environmentally friendly), being non-corrosive (if used properly, with most common construction materials), leaving no residues, and being a vapor. On the other hand, it also poses new challenges in that the equipment is expensive (compared to formaldehyde), it has to be properly distributed inside the room, and fumigation cycles need to be developed for each room and situation. These challenges can be overcome as many laboratories have shown.

In this article the authors outline the development of a VHP fumigation cycle and the validation of said cycle using the example of one laboratory at a new high-containment facility. Problems encountered as well as solutions that were or could have been implemented are also discussed. Even though the process was time-consuming and at times challenging, VHP room fumigation proved to be a versatile and robust process that may be used to efficiently decontaminate even complex laboratory setups.

The lack of published data on effective disinfectants and contact times for use on the fungal pathogens Coccidioides immitis and C. posadasii prompted the authors to investigate the fungicidal activity of three commonly used laboratory disinfectants on arthroconidia harvested from C. immitis strain 2009. They tested the ability of 10% bleach, 70% ethanol, and Vesphene® IIse to inactivate 10⁷ arthroconidia in an aqueous suspension within 1, 2, 5, 10, or 20 minutes of contact time. Both 10% bleach and 70% ethanol provided a 7-log₁₀ reduction in arthroconidia in less than 1 minute, with no growth observed at any of the tested time points. Vesphene® IIse was less effective, providing a 6-log₁₀ reduction in arthroconidia after 5 minutes, but was unable to completely inactivate all of the arthroconidia, even after 20 minutes of contact time.