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>

Steam Sterilization Validation for Implementation of Parametric Release at a Healthcare Facility

2010 ◽  
Vol 44 (2) ◽  
pp. 166-174 ◽  
Author(s):  
Donna Swenson ◽  
Jonathan A. Wilder ◽  
Charles O. Hancock
Keyword(s):  
Quality Assurance ◽  
Product Family ◽  
Healthcare Facility ◽  
Biological Indicator ◽  
Quality Assurance Program ◽  
Steam Sterilization ◽  
Chemical Indicators ◽  
Sterilization Process ◽  
Family Based ◽  
The Cost

Abstract Hospitals are under continual pressure to improve turnaround times for surgical procedures and to find ways to release sterilized product without the need to wait for biological indicator (BI) results. Current procedures used in healthcare do not allow for release of sterilized products based on parameters because hospitals do not validate their sterilization processes. Once a sterilization process is validated for a particular product family, those loads may be released based upon evaluation of the sterilization parameters achieved in the cycle, i.e., parametric release. Typically, hospitals do not perform validation studies to demonstrate that a sterility assurance level (SAL) of 10−6 is being achieved in the sterilized product, relying instead on inactivation of BIs and/or chemical indicators (CIs) in each load. If a healthcare facility can demonstrate achievement of a SAL of 10−6 in a particular product family then it will be possible to release the products in that product family based on achievement of parameters without waiting for BI results. This does not mean that the healthcare facility can eliminate use of all BIs and CIs as part of the criteria for a comprehensive quality assurance program, but dependence on their results and the cost of their use may be greatly reduced. Validation provides another component in a quality assurance program to demonstrate that the highest SAL possible is being provided to patients while still providing the services required by today's healthcare facility.

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.

Appendix

1988 ◽  
Vol 9 (11) ◽  
pp. 506-507
Keyword(s):  
Thermal Resistance ◽  
High Resistance ◽  
Bacillus Stearothermophilus ◽  
Biological Indicator ◽  
False Positives ◽  
Paper Strip ◽  
Resistance Curve ◽  
End User ◽  
Z Value ◽  
D Values

The performance of a biological indicator (BI) over a range of sterilization temperatures is known as a z value and, as defined by Roberts, is “the number of degrees change in temperature to achieve a tenfold change in the D value.” A plot of the D values versus exposure temperatures will reveal the z value as the negative reciprocal of the slope of the resulting thermal resistance curve. Historically, paper strip carriers of Bacillus stearothermophilus spores have been found to possess a z value in the range of l7°-2O°F, whereas self-contained BIs tested in our laboratories have exhibited z values as high as 64°F (Figure I), which reflects their excessively high resistance at flash sterilization temperatures. In general, such matters are not of concern to the end user until such time as false positives are encountered during flash sterilization.

Appendix

1988 ◽  
Vol 9 (11) ◽  
pp. 506-507
Keyword(s):  
Thermal Resistance ◽  
High Resistance ◽  
Bacillus Stearothermophilus ◽  
Biological Indicator ◽  
False Positives ◽  
Paper Strip ◽  
Resistance Curve ◽  
End User ◽  
Z Value ◽  
D Values

The performance of a biological indicator (BI) over a range of sterilization temperatures is known as a z value and, as defined by Roberts, is “the number of degrees change in temperature to achieve a tenfold change in the D value.” A plot of the D values versus exposure temperatures will reveal the z value as the negative reciprocal of the slope of the resulting thermal resistance curve. Historically, paper strip carriers of Bacillus stearothermophilus spores have been found to possess a z value in the range of l7°-2O°F, whereas self-contained BIs tested in our laboratories have exhibited z values as high as 64°F (Figure I), which reflects their excessively high resistance at flash sterilization temperatures. In general, such matters are not of concern to the end user until such time as false positives are encountered during flash 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.

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