Researchers Examine Sterility Maintenance in Potential Emergency Situations

Moist/wet materials stored after autoclaving are considered contaminated and not recommended for use. In a presentation at the International Conference on Prevention & Infection Control (ICPIC) held in Geneva, Switzerland. 29 June 29 through July 2, 2011, Gada Moriya, of the University of Sao Paulo, and Ku Graziano, of the CSSD of the Hospital Alemão Oswaldo Cruz in São Paulo, Brazil described how they evaluated the maintenance of sterility in moist/wet material after being submitted to steam sterilization and stored for a period of 30 days.

As carriers to be incubated in culture medium for proof of sterility, 1,600 porcelain cylinders were attached in surgical instruments. The surgical instruments were inserted into boxes following the recommended surgical care practices. Forty surgical boxes packed in nonwoven cloth covering Spunbound, Meltblown, Spunbound (SMS): half (the experimental group) were placed in an autoclave but the drying phase was interrupted, yielding moist/wet materials and the other half (the negative control group) underwent the complete cycle. The external parts of each surgical box were deliberately contaminated with Serratia marcescens and subsequently stored for 30 days.

The presence of moisture within the surgical boxes were confirmed by differential weight of the boxes before and after autoclaving. After storage, the boxes' contents were submitted to sterility tests and no microbiologial growth was observed. The presence of moisture inside the surgical boxes did not interfere with maintaining their sterility after deliberated external contamination and 30-day storage. The researchers emphasize that their study did not intend to contradict the current recommendations, but only bring scientific evidence to assist in decision making for emergency situations.

Reference: Moriya G and Graziano K. Sterility maintenance assessment of moist/wet material after steam sterilization and 30-day storage. Oral presentation at International Conference on Prevention & Infection Control (ICPIC). 2011. BMC Proceedings 2011, 5(Suppl 6):P316doi:10.1186/1753-6561-5-S6-P316. http://www.biomedcentral.com/1753-6561/5/S6/P316