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.

Processes using chlorine dioxide (CD) gas for the biological decontamination of Class II laminar flow biological safety cabinets (BSCs) have been validated following a protocol developed in conjunction with NSF International. This report reviews the protocol and presents the results of the study. Trials were performed in type A1, A2, B1, and B2 cabinets from two different manufacturers. Exhaust and down-flow HEPA filters were pre-loaded with particulates to enhance the validation challenge. Two methods of CD generation were included within the trials, with one involving the injection of a specific mass of CD gas dependent upon the BSC volume, and the other involving the maintenance of a constant CD gas concentration over the duration of the exposure. In each of the more than 40 experimental trials, 12 biological indicators with ~10 6 Bacillus atrophaeus endospores were deployed at various locations within the BSC to monitor decontamination efficacy.The study validated and qualified CD as an alternative to formaldehyde gas as a decontaminant for BSCs. Acceptable durations for CD exposure of less than 90 minutes were established. Neither residuals from CD nor cabinet material degradation was observed during the trials. Articles

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.

A hospital's life science research facility experienced flooding due to a pipe bursting two floors above. In addition to water damage throughout the facility, mold spores were introduced and distributed throughout. Prior to repairs being made, a full facility decontamination took place to eliminate any mold or mold spores throughout the facility. Chlorine dioxide gas (CD) was chosen as the method of decontamination, which took place over the course of 2 days. Sixteen biological indicators (BI) consisting of Geobacillus stearothermophilus were placed throughout the 145,000 ft 3 facility. A target level of 720 parts-per-million hours (PPM-hr) was targeted to achieve a 6-log sporicidal reduction with an actual exposure of approximately 1,000 PPM-hr exhibited. During the decontamination, the surrounding areas of the facility were occupied, so chemical monitoring took place throughout the event to ensure that facility personnel were not exposed to any leakage. Upon completion of the decontamination, the 16 biological indicators exposed, as well as a positive control BI, were tested for growth. After the incubation period, only the positive control exhibited growth, demonstrating that the decontamination was a success and the facility was free of mold and mold spores.

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