Bio-decontamination of a biomedical research room using gaseous hydrogen peroxide

A single 166m³ room at a Biomedical Services research facility was believed to be contaminated with “Tyzzer’s” disease (Clostridium piliforme) which can infect laboratory subjects. The room also contained equipment including cages, two large isolators and electrical equipment, so would have presented a difficult challenge to conventional decontamination methods.

Solution

The client selected BIOQUELL’s Room Bio-decontamination Service (RBDS) to treat the area. A Clarus™ ‘R’ hydrogen peroxide vapour generator was strategically placed in the room along with two stirring fans to ensure even vapour distribution and two R2 aeration units to remove the H2O2 vapour. An instrumentation module was also included in the room to monitor the key parameters and link the equipment to the external control computer. The room was then sealed before being conditioned, gassed and aerated to remove the hydrogen peroxide vapour. The entire process was monitored and controlled from outside the room via the control computer.

Gassing Cycle Validation

Bacillus stearothermophilus spores dried onto metal carriers at an inoculum of 10⁶ were used as biological indicators (BIs) to validate the gassing cycle. Two BIs were set up in all four corners of the room. Additionally, two ‘challenge’ BIs were positioned behind one of the large isolators and under the sink. A BI map was generated for the target room to trace BI locations (see diagram below).

Gassing Parameters:

The BIs were retrieved after aeration and incubated for seven days at 60^oC. Three control BIs were also incubated that were not exposed to the gassing process. All three control BIs grew successfully. None of the BIs from the test room grew.

Conclusion

The deactivation target of a 6-log reduction in G. stearothermophilus spores was demonstrated in the target room. The Clarus™ R provides a very rapid and effective fumigation system, which combined with the rapid aeration method produces a minimal complete cycle time. The total cycle time was less than 6 hours, which considerably exceeded the customer’s expectations.

This system can be used in many other applications such as fumigation of specific problem-causing micro-organisms or for general decontamination of laboratories, including CL3 facilities, cleanrooms, pharmaceutical manufacturing plants, etc. The Clarus™ R system is infinitely scalable so that very large areas and entire suites can be rapidly and effectively fumigated.

For further details of H2O2 fumigation solutions including equipment and room services, please contact BIOQUELL.