Biomaterial Database

Comparison of a rapid readout biological indicator for steam sterilization with four conventional biological indicators and five chemical indicators. 1996

W A Rutala, and S M Jones, and D J Weber

Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, USA.

OBJECTIVE In this study, we compare a new biological indicator that provides results within 3 hours with four conventional, 48-hour biological indicators and five chemical indicators. METHODS Biological indicators tested included the conventional Attest 1262, Proof Plus, Assert, and Biosign, and the new Attest 1292 Rapid Readout biological indicator. Chemical indicators tested included Comply, Propper, Chemdi, Sterigage, and Thermalog S. Spore survival following 121 degrees C in a gravity displacement sterilizer was measured by media color change after incubation for 24 and 48 hours at 56 degrees C for the conventional biological indicators, fluorescence at 3 hours for the Attest 1292 Rapid Readout biological indicator, and color change for the chemical indicators. Each exposure time was replicated 12 times with 5 samples of each indicator per run (ie, 60 replicates per indicator). RESULTS At 48 hours, the conventional biological indicators Attest 1262, Proof Plus, Assert, and Biosign showed 100%, 95%, 88%, and 93% spore survival at 5 minutes' exposure 0%, 0%, 0% and 8% at 10 minutes; and all showed 0% survival at 15 minutes' exposure. Following a 3-hour incubation, the Attest 1292 Rapid Readout biological indicator showed fluorescence at 100%, 72%, and 0% at 5, 10, and 15 minutes, respectively. The chemical indicators Comply, Propper, Chemdi, Sterigage, and Thermalog S revealed sterilization failure rates of 100%, 100%, 100%, 100%, and 100% at 5 minutes' exposure; 0%, 0%, 0%, 92%, and 100% at 10 minutes; and 0%, 0%, 0%, 3%, and 27% at 15 minutes' exposure, respectively. CONCLUSIONS The sensitivity of the Attest 1292 Rapid Readout biological indicator parallels that of conventional biological indicators. These data suggest that a 3-hour rapid readout biological indicator is equivalent to a standard 48-hour biological indicator. Some chemical indicators (eg, Thermalog S) failed to indicate adequate sterilization at 15 minutes' exposure. These chemical indicators have the potential of causing unnecessary recall of adequately sterilized items.

UI	MeSH Term	Description	Entries
D011786	Quality Control	A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required. (Random House Unabridged Dictionary, 2d ed)	Control, Quality,Controls, Quality,Quality Controls
D011934	Reagent Strips	Narrow pieces of material impregnated or covered with a substance used to produce a chemical reaction. The strips are used in detecting, measuring, producing, etc., other substances. (From Dorland, 28th ed)	Reagent Strip,Strip, Reagent,Strips, Reagent
D004866	Equipment Contamination	The presence of an infectious agent on instruments, prostheses, or other inanimate articles.	Contamination, Equipment,Contaminations, Equipment,Equipment Contaminations
D012680	Sensitivity and Specificity	Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)	Specificity,Sensitivity,Specificity and Sensitivity
D013171	Spores, Bacterial	Heat and stain resistant, metabolically inactive bodies formed within the vegetative cells of bacteria of the genera Bacillus and Clostridium.	Bacterial Spores,Bacterial Spore,Spore, Bacterial
D013242	Sterilization	The destroying of all forms of life, especially microorganisms, by heat, chemical, or other means.
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D015203	Reproducibility of Results	The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.	Reliability and Validity,Reliability of Result,Reproducibility Of Result,Reproducibility of Finding,Validity of Result,Validity of Results,Face Validity,Reliability (Epidemiology),Reliability of Results,Reproducibility of Findings,Test-Retest Reliability,Validity (Epidemiology),Finding Reproducibilities,Finding Reproducibility,Of Result, Reproducibility,Of Results, Reproducibility,Reliabilities, Test-Retest,Reliability, Test-Retest,Result Reliabilities,Result Reliability,Result Validities,Result Validity,Result, Reproducibility Of,Results, Reproducibility Of,Test Retest Reliability,Validity and Reliability,Validity, Face