Hydrogen Peroxide Gas Plasma Sterilization Research Articles

Evaluation and quantification of reprocessing modification in single-use devices in interventional cardiology

The increasing demand in interventional cardiology urges for reprocessing of single-use-labelled medical devices. To fulfil this aim, accurate and validated regeneration protocols are mandatory to guarantee sterility, functionality and safeness. The reprocessing protocol was realized by decontamination with chloro-donors, cleaning with enzymatic solutions and hydrogen peroxide gas plasma sterilization. Reprocessing effects on ablation and electrophysiology catheters were evaluated by assessing physical–chemical changes on surfaces and bulks, as a function of the reprocessing cycles number. Conventional optical microscopy and environmental scanning electron microscopy (ESEM) underlined the presence of micro-scratches on the polyurethane shaft surface. A clear correlation was found between surface damages and number of reprocessing cycles. Atomic force microscopy (AFM) confirmed the occurrence of physical–chemical etching of the polyurethane shaft caused by the hydrogen peroxide plasma sterilization, with increasing of nano-roughness at increasing number of the reprocessing cycles. UV–Vis spectra performed on the incubation solution of polymeric shaft sample, showed an absorbance increase at about 208nm. This fact could be attributed to the water elution from the polymer of low molecular weight oligomers. The presence of hydrolysis products of the polymeric shaft after incubation demands both the characterization of the products released in the solution and the chemical characterization of the water exposed surface.

Contamination of bronchoscopes with Mycobacterium tuberculosis and successful sterilization by low-temperature hydrogen peroxide plasma sterilization

Background: The transmission of mycobacteria by bronchoscopes has been reported several times in the last years. To explore methods to prevent transmission of tuberculosis in this way, we sterilized contaminated bronchoscopes with low-temperature hydrogen peroxide gas plasma sterilization. Methods: Bronchoscopes were contaminated with Mycobacterium tuberculosis and decontaminated with a washer/disinfecter (“normal washing”). Some were additionally disinfected with glutaraldehyde (“intensive washing”). Afterward the bronchoscopes were sterilized by low-temperature hydrogen peroxide plasma sterilization. Results: After normal washing, 8/17 samples had positive results by culture, and 7/17 had positive results by nucleic acid amplification technique. After intensive washing, all samples had negative results by culture, and 10/25 had positive results by nucleic acid amplification technique; after sterilization with low-temperature hydrogen peroxide plasma sterilization, all samples had negative results by culture and nucleic acid amplification technique. Conclusion: Washing of bronchoscopes, as performed normally, is not sufficient for decontamination of bronchoscopes. Additional disinfection is recommended. If the nucleic acid amplification technique is used for diagnostic procedures, sterilization by low-temperature hydrogen peroxide plasma sterilization is recommended to avoid false-positive results.

Effect of gas-plasma sterilization on the osteoinductive capacity of demineralized bone matrix.

The current study evaluated the effect of low-temperature hydrogen peroxide gas plasma sterilization on the osteoinductive capability of human demineralized bone matrix using a rat model. Twelve athymic rats received three separate implants consisting of steam-sterilized demineralized bone matrix (negative control), sterile-harvest demineralized bone matrix (positive control), and gas-plasma-sterilized demineralized bone matrix. A demineralized bone matrix pellet from each sterilization group was placed individually into one of three separate soft tissue pockets created in the epaxial musculature of each rat. All 12 rats were euthanized 9 weeks after implantation. Each implantation site was removed along with 0.5-cm normal tissue around the implant. Histologic examination was done on each implant site to determine the presence or absence of new bone, cartilage, or bone marrow elements. All 12 sterile harvest demineralized bone matrix sites histologically contained new bone elements, whereas none of the negative control or gas plasma sterilized demineralized bone matrix sites contained any of these same elements. The results of this study indicate that demineralized bone matrix sterilized with low-temperature, gas-plasma sterilization loses its osteoinductive capacity in a manner similar to that of steam-sterilized demineralized bone matrix, making low-temperature, gas- plasma sterilization unsuitable as a method of secondary sterilization of demineralized bone matrix.

The presterilization microbial load on used medical devices and the effectiveness of hydrogen peroxide gas plasma against Bacillus subtilis spores.

To determine the microbial load found on used critical medical devices (5 spinal anesthesia needles, 21 catheters, and 28 sheaths) prior to sterilization and to evaluate the effectiveness of hydrogen peroxide gas plasma against inoculated Bacillus subtilis var globigii (American Type Culture Collection 9372) spores. Membrane filter and pour-plate methods were applied to estimate total microbial loads (aerobic and anaerobic, mesophilic and thermophilic, vegetative and spore forms). Spinal anesthesia needles (102 units) and sheath components (61 units) were inoculated with a suspension of B. subtilis spores. After drying, the devices were sterilized with hydrogen peroxide gas plasma. Higher counts of aerobic, mesophilic, and fungal organisms were recovered when the drying period was insufficient. Anaerobic spores were not found in any analyzed presterilization items. The hydrogen peroxide gas plasma effected a 5 to 7 log10-fold reduction in B. subtilis spore counts in well-dried needles and sheath components. The success of hydrogen peroxide gas plasma sterilization depends mostly on educating the staff to assure well-cleaned and dried reusable medical devices, allowing penetration of the hydrogen peroxide gas plasma into the critical points of the items and providing a reduction in organisms.

Inactivation of Duck Hepatitis B Virus by Hydrogen Peroxide Gas Plasma Sterilization

Inactivation of Duck Hepatitis B Virus by Hydrogen Peroxide Gas Plasma Sterilization

Inactivation of duck hepatitis B virus by a hydrogen peroxide gas plasma sterilization system: laboratory and ‘in use’ testing

Human hepatitis B virus (HBV) is an important cause of nosocomial infections and can be transmitted by contaminated instruments. However, tests of the efficacy of sterilization of materials and equipment contaminated by HBV are difficult to perform because the virus cannot be cultured in the laboratory. In this study, we aimed to evaluate the capability of a low temperature, hydrogen peroxide gas plasma sterilizer (Sterrad®, Advanced Sterilization Products, Irvine California,) to inactivate duck hepatitis B virus (DHBV). In laboratory efficacy studies using DHBV dried on to glass filter carriers and exposed to one-half of the hydrogen peroxide gas plasma sterilization process, there was a 107or greater decrease in the viral titer, with no infectivity detected on the carriers after treatment. In-use studies were performed using a laparoscope that was experimentally contaminated with DHBV to mimic the possible transmission of infection between successive patients. Following exposure to the hydrogen peroxide gas plasma sterilization process no transmission of DHBV infection from the laparoscope occurred despite obvious visual soiling with blood (N=8) while the transmission rate for the unprocessed laparoscope (positive control) was 100% (26/26), and that for instruments after a water wash was 63% (7/11). In conclusion the hydrogen gas plasma sterilization process completely inactivates DHBV a representative of the hepadna group of viruses.

Safety and efficacy of hydrogen peroxide plasma sterilization for repeated use of electrophysiology catheters

Objectives. The purpose of this study was to evaluate a new technique for sterilizing nonlumen electrophysiology catheters that uses hydrogen peroxide gas plasma.Background. The reuse of electrophysiology catheters may potentially result in a significant cost savings. While ethylene oxide sterilization appears to be safe and effective from a clinical standpoint, toxic ethylene oxide residuals, which exceed Food and Drug Administration standards, have been reported.Methods. Ten nonlumen electrophysiology catheters were extensively evaluated. Each catheter was used five times and resterilized after each use with hydrogen peroxide gas plasma. Tests for sterility, mechanical and electrical integrity, chemical residuals and standard and electron microscopic inspection were performed.Results. Loss of electrical integrity or mechanical integrity was not observed in any catheter. No evidence of microbial contamination was found. Surface integrity was preserved except for one ablation catheter that exhibited fraying of the insulation at the insulation-electrode interface. Surface inspection using standard magnification and electron microscopy revealed no significant change in surface characteristics associated with the sterilization process. Hydrogen peroxide was the only chemical residual noted, with an average concentration of 0.22% by weight, which is within accepted American Association for the Advancement of Medical Instrumentation limits. The cost for a standard electrophysiology catheter ranges from $200 to $800, and one sterilization cycle costs $10. If electrophysiology catheters are used five times, resterilization could potentially result in a savings of $2,000 per catheter, or $9,000 for five ablation procedures.Conclusions. Hydrogen peroxide gas plasma sterilization may provide a cost-effective means of sterilizing nonlumen electrophysiology catheters without the problem of potentially harmful chemical residuals. However, careful visual inspection of catheters, particularly at the insulation–electrode interface, is required if catheter reuse is performed.

Hydrogen Peroxide Gas-Plasma Sterilization Studies on Viruses and Oocysts

Hydrogen Peroxide Gas-Plasma Sterilization Studies on Viruses and Oocysts

Comparison of the effects of gamma radiation and low temperature hydrogen peroxide gas plasma sterilization on the molecular structure, fatigue resistance, and wear behavior of UHMWPE

The effects of gamma radiation and low temperature hydrogen peroxide gas plasma (HPGP) sterilization on structure and cyclic mechanical properties were examined for orthopedic grade ultra-high-molecular-weight polyethylene (UHMWPE) and compared to each other as well as to no sterilization (control). Density was monitored with a density gradient column and was found to be directly influenced by the sterilization method employed: Gamma radiation led to an increase, while plasma did not. Oxidation of the polymer was studied by observing changes in the carbonyl peak with Fourier transform infrared spectrometry and was found to be strongly affected by both gamma radiation and subsequent aging, while plasma sterilization had little effect. Gamma radiation resulted in embrittlement of the polymer and a decreased resistance to fatigue crack propagation. This mechanical degradation was a direct consequence of postradiation oxidation and molecular evolution of the polymer and was not observed in the plasma-sterilized polymer. Both gamma radiation and plasma sterilization led to improved wear performance of the UHMWPE compared to the nonsterile control material.

Inactivation of human immunodeficiency virus type 1, hepatitis A virus, respiratory syncytial virus, accinia virus, herpes simplex virus type 1, and poliovirus type 2 by hydrogen peroxide gas plasma sterilization

Studies were conducted to determine the capability of a hydrogen peroxide gas plasma sterilization process to inactivate several types of viruses. Six test agents were used: HIV type 1, human hepatitis A virus, respiratory syncytial virus, vaccinia, herpes simplex virus type 1, and poliovirus type 2. The test viruses were suspended in cell culture medium and dried on the bottom of sterile glass petri dishes. The inoculated dishes were processed in the hydrogen peroxide gas plasma system for half the normal sterilization cycle time. Four inoculated carriers for each virus were used in two separate half cycles. Infectivity of the test viruses and cytotoxicity to the indicator cell lines were assayed. The hydrogen peroxide gas plasma sterilization process produced inactivation of the six viral test agents under these experimental conditions. The reduction in viral titers ranged from 2.5 log10 to 5.5 log10, a 99.68% to 99.999% decrease. These results clearly demonstrate the virucidal effectiveness of the hydrogen peroxide gas plasma sterilization process against both lipid and nonlipid viruses.

Hydrogen peroxide gas plasma sterilization is effective against Cryptosporidium parvum oocysts

The aim of this work was to evaluate in an immunosuppressed rat cryptosporidiosis model a new method that combines vacuum and low-temperature hydrogen peroxide gas plasma for sterilization of endoscopic material contaminated by Cryptosporidium parvum. Rats were challenged with oocysts either air-dried or air-dried and treated with vacuum alone or associated with gas plasma. No rat was found infected after gas plasma exposure of oocysts, whereas vacuum or air-drying alone resulted only in a decreased infectivity.

Mars 96 small station biological decontamination

In the context of extraterrestrial exploration missions and since the beginning of solar system exploration, it is required, according to the article IX of the Outer Space Treaty (London/Washington January 27, 1967) to preserve planets and the Earth from cross contamination. Consequently, COSPAR (Committee of Space Research) has established some planetary protection recommendations in order to protect the environments of other worlds from biological contamination by terrestrial microorganisms, to protect exobiological science for searching for life on planets, and to protect the Earth's environment from back contamination. For the upcoming Mars exploration missions, and after updating the planetary protection recommendations, a biological decontamination program has been designed for Mars 96 landers. After sterilization or biocleaning of equipment and instruments, these are integrated into a cleanroom and kept in sterile conditions with recontamination control in order to satisfy the surface contamination requirements. The Mars 96 orbiter does not need any implementation of sterilization procedures because the probability of spacecraft crash does not exceed 10 −5 and because it's orbit is in accordance with quarantine requirements (orbit lifetime with 0.9999 confidence for the first 20 years and 0.95 confidence during the next 20 years). For the Mars 96 small stations, different methods have been used and especially for the French and Finnish payload, a complete description of hydrogen peroxide gas plasma sterilization will be given, including bioburden assessments and sterility level determination. Probe integration implementation and procedures are described in the second part of this paper.

Assessment of the efficacy of a low temperature hydrogen peroxide gas plasma sterilization system

The STERRAD 100 sterilization system (Johnson & Johnson Medical Ltd) uses low temperature hydrogen peroxide gas plasma for sterilization of heat labile equipment. The efficacy of the machine was tested by contaminating a standard set of instruments with different organisms and using a filtration method to assess recovery of organisms from the wash fluids of instruments post-sterilization. Experiments were performed under clean (the organism only) and dirty (organism mixed with egg protein) conditions. A parallel study conducted using a 3M STERIVAC ethylene oxide sterilizer could not be completed owing to closure of the ethylene oxide plant. For sterilization of instruments with long and narrow lumens, hydrogen peroxide adaptors are necessary. The STERRAD 100 sterilizer can achieve effective sterilization of heat labile instruments with a reduction of 6 log 10 cfu/mL of organisms tested. This method has the advantages over ethylene oxide sterilization of safety, ease of maintenance and no requirement for aeration time.