Fluorimetric Detection of a Bacillus stearothermophilus Spore-Bound Enzyme, alpha-d-Glucosidase, for Rapid Indication of Flash Sterilization Failure.

A biological indicator based on fluorimetric detection within 60 min of a Bacillus stearothermophilus spore-bound enzyme, alpha-d-glucosidase, has been developed. Results indicate that the enzyme survived slightly longer than spores observed after 24 h of incubation. The new system shows promise for evaluating flash sterilization cycles within 60 min compared with conventional 24-h systems.

Microbial contamination associated with routine aseptic practice.

We have studied the rate of fortuitous contamination associated with routine aseptic technique under operational conditions. Stainless steel strips, as simulators of surgical instruments, were contained in sterilized surgical packs and assayed by nursing personnel during surgical and other invasive procedures at three different hospitals. The rates of contamination observed for the 36 investigators ranged from 0% to 11.3%, with an overall rate of 2.7%. Assays conducted in a clean room environment, under conditions approaching industrial sterility standards, showed a contamination rate of 0.16%. We concluded that aseptic practices, as routinely performed without any noticeable breaks or transgressions, do not guarantee sterility. The concept of surgical sterility implies low level, but measurable, microbial contamination.

Effect of long-term storage on sterile status of devices in surgical packs.

We investigated the effect of the following on the sterile integrity of surgical packs: four wrapping materials (two-ply reusable, nonbarrier wovens, both new and previously used; disposable, barrier nonwovens; and polypropylene peel pouches), dustcovers, two storage locations, and storage times ranging from 2 to 50 weeks. Two hundred sixty-three packs containing stainless steel coupons were prepared, wrapped, sterilized, and stored. Half of the packs were dustcovered prior to storage. At monthly intervals for a year, packs of each type were opened in a laminar flow hood, and the coupons inoculated into trypticase soy broth. The coupon contamination probabilities were 0.019 for reusable, woven packs; 0.017 for disposable, nonwoven packs; and 0.016 for peel pouches. These differences were not significant. The probability of finding a contaminated coupon in any pack after 50 weeks was 0.018. No trend toward increased probability of contamination over time was observed for any of the pack types studied.

Interhospital transportation. Monitoring sterility of instrument packs.

The Minneapolis-St Paul area is currently experiencing an increase in health care mergers among hospitals. As new facilities are acquired, whether through merger or the building of satellite hospitals, economic considerations often instigate the consolidation of certain departments and services. Thus, hospitals are confronted with a new set of management problems. One such problem might be determining if the probability of contamination increases when a sterile pack is transported from the central sterile supply department of one hospital to the operating room of another hospital. This study indicates that interhospital transport of surgical packs, using a specially designed transfer system, can be accomplished without compromising the sterile status to a significantly greater degree than that associated with transport within a hospital. Many more samples would have to be assayed before these results could be considered conclusive. This study proposes a simple, reproducible, microbiologically sensitive and statistically satisfactory test to monitor the sterile integrity of surgical packs. In the past, different sterility monitoring methods proposed have required either special equipment, specially trained personnel, or complicated procedures. The assay method described here can be easily used by central sterile supply department personnel to monitor the sterile status of transported or stored surgical packs.