In May of 2004, the large animal intensive care and neonatal intensive care units (ICU/NICU) of the University ofPennsylvania's New Bolton Center were temporarily closed to all admissions following an outbreak of salmonellosis that had affected its patients. Environmental testing continued to recover a multi-drug resistant organism identified as Salmonella enterica serovar Newport following repeated liquid disinfection treatments of the facility. Based upon various environmental considerations, it was decided that the most feasible and effective process for disinfecting the facility would be achieved using chlorine dioxide (ClO 2 ) gas. The facility was appropriately sealed, supplied with gas distribution mechanisms and demonstrated to have met the specification for humidity before introduction of ClO 2 . The total exposure for this 4800 cubic meters structure was approximately 400 ppm-hr. Efficacy of the decontamination was monitored by the placement of 20 Bacillus atrophaeus spore, 40 Geobacillus stearothermophilus spore, and 40 Salmonella Newport vegetative cell strips. Microbiological testing demonstrated greater than 5.5 and 6.1 log reduction for the G. stearothermophilus and B. atrophaeus spore strips, respectively. Log reductions of the S. Newport bacterial strips were also within acceptable levels. The success of this project demonstrates the utility of ClO 2 gas as a biological decontaminant approach for mid-sized commercial and public facilities.

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The following article describes a case study about decontamination of a 65-room new animal research facility located in the Northeast. The decontamination took place during the cold winter month of January, and all equipment used to run the facility was in place prior to beginning the decontamination. This facility had an essential need for complete decontamination because a lot of its equipment was procured from other facilities and crosscontamination was a concern. Chlorine dioxide gas was used due to the inherent properties of a gas, such as excellent distribution and penetration which were required due to the numerous rooms in the facility. The target concentration was not reached, but since photometric measurement was utilized, the exposure was extended ac cordingly and the end result was successful. All biological indicators were eradicated, and no residues and no material degradation were observed. Facility DescriptionThe end-user of a new 65-room, 18,000 sq ft (180,000 cu ft / 5097 cu m) life science research facility required decontamination prior to the opening and occupying of the facility. The entire area was to be decontaminated prior to moving in the animals, since some of the equipment was previously used at another facility and the possibility of cross-contamination needed to be eliminated.Chlorine dioxide gas was used to fully decontaminate the area. The facility contained a variety of rooms such as a chemistry lab, animal holding rooms, procedure rooms, a cage wash room, bathrooms/showers, etc. No offices were located within the decontamination area. All the equipment needed to run the facility was in place prior to the decontamination. Various types of equipment, such as rodent racks and cages, bedding changing stations, biological safety cabinets, various plastics (for example, cages and water bottles), microscopes, video cameras, circuit-breaker panels, bathrooms and showers, smoke detectors, temperature and relative humidity (RH) sensors, as well as various analytical and electronic equipment used in a typical chemistry lab, were stored within the facility. All surfaces in the area were clean and non-porous, including stainless steel, epoxy-painted walls, solid flooring, painted steel cabinets, and plastic light fixtures. The facility was cleaned prior to the decontamination. Background Information: Determine What Method to UseTo perform a facility decontamination, a choice had to be made to determine which decontamination agent to utilize. In this case three were considered: formaldehyde gas, vapor phase hydrogen peroxide (VPHP), and chlorine dioxide (CD) gas. All were known to be effective decontaminants for spore and non-spore forming bacteria under ideal laboratory conditions (i.e., clean flat surfaces lacking porous materials or potential dead-legs with which fumigant penetration might be retarded). Formaldehyde GasFormaldehyde gas is the agent that is probably used most frequently when compared to CD gas and VPHP . It is used most often because it is effective (gets good kill)...

A unique cryo-electron microscopy facility has been designed and constructed at the University of Texas Medical Branch (UTMB) to study the three-dimensional organization of viruses and bacteria classified as select agents at biological safety level (BSL)-3, and their interactions with host cells. A 200 keV high-end cryo-electron microscope was installed inside a BSL-3 containment laboratory and standard operating procedures were developed and implemented to ensure its safe and efficient operation. We also developed a new microscope decontamination protocol based on chlorine dioxide gas with a continuous flow system, which allowed us to expand the facility capabilities to study bacterial agents including spore-forming species. The new unified protocol does not require agent-specific treatment in contrast to the previously used heat decontamination. To optimize the use of the cryo-electron microscope and to improve safety conditions, it can be remotely controlled from a room outside of containment, or through a computer network world-wide. Automated data collection is provided by using JADAS (single particle imaging) and SerialEM (tomography). The facility has successfully operated for more than a year without an incident and was certified as a select agent facility by the Centers for Disease Control.