Evaluation of a Rapid Readout Biological Indicator for Flash Sterilization with Three Biological Indicators and Three Chemical Indicators

1993 ◽  
Vol 14 (7) ◽  
pp. 390-394 ◽  
Author(s):  
William A. Rutala ◽  
Maria F. Gergen ◽  
David J. Weber
Keyword(s):  
Enzyme Activity ◽  
Bacillus Stearothermophilus ◽  
Color Change ◽  
Safety Margin ◽  
Biological Indicators ◽  
Biological Indicator ◽  
Processing Conditions ◽  
Fluorescent Product ◽  
Chemical Indicators ◽  
Chemical Indicator

AbstractObjective:Flash sterilization is most commonly used for emergency sterilization of unwrapped items in a gravity displacement sterilizer for three minutes. Sterilization quality assurance is monitored by biological indicators that require a 24-hour incubation prior to reading. In this study, we compared a new biological indicator that provides results within 60 minutes with three conventional, 24-hour biological indicators for monitoring flash sterilization and three chemical indicators.Design:Conventional biological indicators tested included the conventional Attest 1261, Proof Flash and Assert, while the rapid readout indicator tested was Attest 1291. Attest Rapid Readout detects the presence of aBacillus stearothermophilusenzyme by reading a fluorescent product that is produced by the enzymatic break-down of a nonfluorescent substrate. Chemical indicators tested included Comply, Incheque, and Thermalog S. Survival at 132°C in a gravity displacement sterilizer was measured by media color change after incubation for 24 hours at 56°C for the three conventional biological indicators, fluorescence at 60 minutes for the Attest Rapid Readout biological indicator, and color change for the chemical indicators. Each exposure time was replicated four times with 10 of each biological and chemical indicator per run.Results:The conventional biological indicators (Attest, Proof Flash, and Assert) had 90%, 48%, and 40% spore survival at two minutes exposure; 23%, 3%, and 0% at three minutes exposure; and 3%, 0%, and 0% at four minutes exposure respectively. The Attest Rapid Readout biological indicator had 88%, 33%, and 0% enzyme activity detectable at 2, 3, and 4 minutes exposure. The chemical indicators Comply, Incheque, and Thermalog S revealed sterilization failure rates of 100%, 100%, and 100% at 0 minutes exposure; 100%, 100%, and 45% at one minute; 0%, 0%, and 28% at two minutes exposure; 0%, 0%, and 18% at three minutes exposure; and 0%, 0%, and 0% at four minutes exposure, respectively.Conclusion:The sensitivity of the Attest Rapid Readout parallels the conventional biological indicators. These data suggest that a 60-minute rapid readout biological indicator is equivalent to the 24-hour biological indicators. If further studies demonstrate that a four-minute flash sterilization cycle provides a needed safety margin to ensure sterilization, then consideration should be given to requiring a four-minute flash sterilization cycle. Chemical indicators were too sensitive to the processing conditions (eg, steam) and are inadequate to ensure adequate sterilization.

Comparison of a Rapid Readout Biological Indicator for Steam Sterilization With Four Conventional Biological Indicators and Five Chemical Indicators

1996 ◽  
Vol 17 (7) ◽  
pp. 423-428 ◽  
Author(s):  
William A. Rutala ◽  
Suzanne M. Jones ◽  
David J. Weber
Keyword(s):  
Exposure Time ◽  
Color Change ◽  
Biological Indicators ◽  
Biological Indicator ◽  
Failure Rates ◽  
Steam Sterilization ◽  
Chemical Indicators

AbstractObjective: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.Design: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°C in a gravity displacement sterilizer was measured by media color change after incubation for 24 and 48 hours at 56°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 five 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 3hour 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 3hour 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.

An Evaluation of Three Biological Indicator Systems in Flash Sterilization

1987 ◽  
Vol 8 (8) ◽  
pp. 311-316 ◽  
Author(s):  
Helen Rosen Kotilainen ◽  
Nelson M. Gantz
Keyword(s):  
Exposure Time ◽  
Color Change ◽  
Biological Indicators ◽  
Biological Indicator ◽  
The Other ◽  
Minute Exposure ◽  
Color Changes ◽  
Indicator Systems

AbstractAn evaluation of two flash-sterilization-specific biological indicators (BI) and a traditional spore strip indicator was performed to assess sensitivity and reliability as reflected in survive/kill ratios. The Bis tested included: 3M's Attest® #1261, Amsco's Proof Flash™, and Castle® Tec Test. Survival after “come-up” time alone, (0 exposure) and one-, two-, and three-minute exposures at 273°F in a gravity displacement sterilizer was measured by media color change or turbidity after incubation at 55°C. Each cycle was replicated three times on two separate days with six of each BI per run. Positive Bis were subcultured as necessary. Proof Flash presented technical difficulties due to incomplete or impossible crushing of media vials, unexpected media color changes, and evaporation of media. Tec Test was not sufficiently resistant as survivors were not detected at any exposure time. The Attest had 100% survival at zero and one-minute exposures and 94% survival after the two-minute exposure. No survivors were detected after the three-minute exposure. Although each institution should evaluate Bis for their own use independently, the data indicate that Attest #1261 monitored the three-minute flash cycles more satisfactorily than the other Bis tested.

scholarly journals Efficiency Evaluation of Hospitals Sterilization by Biological and Chemical Methods

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Davood Ahmadi ◽  
Abdolmajid Fadaei
Keyword(s):  
Loading Rate ◽  
Biological Indicator ◽  
Biological Index ◽  
Chemical Methods ◽  
Chemical Indicators ◽  
Color Circle ◽  
Location Type ◽  
And Control ◽  
Chemical Indicator ◽  
Light Medium

Autoclaving is one of the methods which sterilizes medical solidwaste. This study was carried out to evaluate efficiency of autoclaves in two Shahrekord hospitals(Kashani and Hajar) in Iran by biological and chemical indicators. In this study, the performance of autoclave was studied based on biological and chemical through setting 96 tests. Variables were loading type in four groups (light, medium, semi- heavy, and heavy), location, type of hospital , and temperature-135°C, time10min features in fixed pressure equal to 4.2 bar. Biological and chemical indicators were ATCC 7953 which contained Stearotermophilus Geobacillus spores ,and chemical indicator Class 6 with three color circle as weekly, respectively.The best autoclave operational condition based on biological indicator in both hospitals were light loading rate in Kashani and Hajar 66%(8), and 75%(9) desirable results, respectively. Each four loading rate level based on biological and chemical indicators the Hajar hospital with 68% desirable results were more efficiency than Kashani hospital with57% desirable results. According to results of this study (biological index) sterilization failure in kashani and Hajar hospitals were 65%, and 50%, respectively.There is an increased need for suitable regulation and control of autoclave devices and for monitoring and suitable handling of these devices in developing countries.

scholarly journals Influence of Bacillus Stearothermophilus generations in the production of its spores

2010 ◽  
Vol 1 (1) ◽  
pp. 53
Author(s):  
Roselene Ferreira Oliveira ◽  
Heron Oliveira dos Santos Lima ◽  
Mirela Vanin dos Santos Lima
Keyword(s):  
Quality Assurance ◽  
Thermal Resistance ◽  
Bacillus Stearothermophilus ◽  
Culture Media ◽  
Biological Indicators ◽  
Biological Indicator ◽  
Physical Parameters ◽  
Steam Sterilization ◽  
Sporulation Process ◽  
Pharmaceutical Industries

<p>The validation of sterilization processes in food and pharmaceutical industries is a major tool for quality assurance, making the products safe, effective and reliable. Biological indicators, formed by spores of Bacillus stearothermophilus microorganisms considered at higher thermal resistance, are used to evaluate and monitor the physical parameters of a cycle of steam sterilization. In this way this study aimed to cultivate and characterize the microorganism Bacillus stearothermophilus generations, assessing the influence of these generations in the parameters of resistance, formation and concentration of its spores to be used in the production of biological indicators. The experiments were conducted cultivating the 1st, 2nd and 3rd generations of B. stearothermophilus in suitable culture media for sporulation, in Roux bottles, for a period of 15 days of incubation. During these 15 days, the sporulation process was evaluated by microscopy, according to Wirtz-Conklin's method, every 24 hours of incubation. The results showed that the generations do influence the sporulation process, indicating that the 3rd generation is the most suitable for the production of formed spores, in concentration and thermal resistance appropriate characteristics to the needs of a biological indicator to efficiently validate and monitor steam sterilization cycles.</p><p>&nbsp;</p><p><a href="http://dx.doi.org/10.14685/rebrapa.v4i1.116">http://dx.doi.org/10.14685/rebrapa.v1i1.12</a></p>

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