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):  
Biological Indicators ◽  
Biological Indicator ◽  
Chemical Indicators

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.

When the Biological Indicator Is Positive: Investigating Autoclave Failures

1997 ◽  
Vol 18 (09) ◽  
pp. 654-656 ◽  
Author(s):  
E.A. Bryce ◽  
F.J. Roberts ◽  
B. Clements ◽  
S. MacLean
Keyword(s):  
Biological Indicators ◽  
Biological Indicator

Abstract A series of positive biological indicators in steam autoclaves from different hospital departments within the same building were traced to blocked steam traps on building condensate lines. The steps taken during the investigation and a protocol for management of positive biological indicators are described.

scholarly journals FLUCTUATIONS OF MINERAL NITROGEN AND PHOSPHATE IN RIVER WATER DURING PERIODS OF VARIOUS WETNESS

2005 ◽  
Vol 13 (3) ◽  
pp. 132-140
Author(s):  
Lina Bagdžiūnaite-Litvinaitiene
Keyword(s):  
Water Quality ◽  
Statistical Parameter ◽  
Biological Indicators ◽  
Biological Indicator ◽  
Sampling Frequency ◽  
Mineral Nitrogen ◽  
Essential Difference ◽  
Water Sampling ◽  
The European Union ◽  
Run Off

Biological indicators are the best indicators of water quality, since they are interpretive of a variety of Stressors. Analysis of scientific literature shows that substance flows are calculated using different methods. One of the goals of this work is to investigate various methods for calculating biological indicator flows and to compare differences among them. For the four biological substance calculation methods which were studied, an essential difference among them was the period during which the volume of run‐off was calculated, that largely influences the size of flows. Upon Lithuania's entry into the European Union, the Water Framework Directive (2000/60/EC) is the principle document defining priorities in the establishment and management of water quality. It foresees optimizing the number of water samplings per year. Therefore, another goal of this work is to identify possibilities for reducing water sampling frequency. The variation coefficient, as a statistical parameter showing fluctuations in the concentration of biogenic substances over the course of time, was selected for the analysis. Possibilities for reducing water sampling frequency for establishing the concentration of mineral nitrogen and phosphates in river surface waters were determined according to the obtained results.

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