Accelerated Hydrogen Peroxide Research Articles

Early identification of a ward-based outbreak of Clostridioides difficile using prospective multilocus sequence type-based Oxford Nanopore genomic surveillance.

To describe an outbreak of sequence type (ST)2 Clostridioides difficile infection (CDI) detected by a recently implemented multilocus sequence type (MLST)-based prospective genomic surveillance system using Oxford Nanopore Technologies (ONT) sequencing. Hemato-oncology ward of a public tertiary referral centre. From February 2022, we began prospectively sequencing all C. difficile isolated from inpatients at our institution on the ONT MinION device, with the output being an MLST. Bed-movement data are used to construct real-time ST-specific incidence charts based on ward exposures over the preceding three months. Between February and October 2022, 76 of 118 (64.4%) CDI cases were successfully sequenced. There was wide ST variation across cases and the hospital, with only four different STs being seen in >4 patients. A clear predominance of ST2 CDI cases emerged among patients with exposure to our hemato-oncology ward between May and October 2022, which totalled ten patients. There was no detectable rise in overall CDI incidence for the ward or hospital due to the outbreak. Following a change in cleaning product to an accelerated hydrogen peroxide wipe and several other interventions, no further outbreak-associated ST2 cases were detected. A retrospective phylogenetic analysis using original sequence data showed clustering of the suspected outbreak cases, with the exception of two cases that were retrospectively excluded from the outbreak. Prospective genomic surveillance of C. difficile using ONT sequencing permitted the identification of an outbreak of ST2 CDI that would have otherwise gone undetected.

A cluster of Candida parapsilosis displaying fluconazole-trailing in a neonatal intensive care unit successfully contained by multiple infection-control interventions.

This study aimed to investigate and contain a cluster of invasive candidiasis cases caused by fluconazole-resistant Candida parapsilosis (FRC) in a neonatal intensive care unit. Active surveillance was initiated. Direct observations of hand-hygiene compliance (HHC) among staff were conducted before and after the implementation of hand-hygiene (HH) education. Thirty-five environmental cultures were obtained. Phylogenetic analysis of FRC was performed using Fourier-transform infrared spectroscopy and microsatellite genotyping. A total of 14 patients (mean birth weight = 860 g, gestational age = 25 weeks) infected with FRC were identified using the fully automated analyzer, including 5 with clinical infection (three with catheter-related bloodstream infection, one with cutaneous infection, and one with fatal peritonitis) and 9 with colonization. The HHC rate in nurses before performing a sterile or aseptic procedure significantly improved after the HH education (P < .05). Sinks near the patients were contaminated with FRC. All FRC strains were confirmed to be susceptible to fluconazole using the CLSI method, and the microdilution procedure indicated a trailing effect. Phylogenetic analysis showed that all the fluconazole-trailing isolates from patients were clustered together and had the same genotype. Sinks were successfully decontaminated using accelerated hydrogen peroxide and drainage pipes were replaced. Ultraviolet-C decontamination was applied in the milk preparation room. No new cases were detected after the education and disinfection interventions. Sinks are an important reservoir of C. parapsilosis. Active surveillance, environmental hygiene, and constant staff education on maintaining a high level of HHC are necessary to limit the spread of C. parapsilosis.

In vitro assessment of antibacterial and antiviral activity of three copper products after 200 rounds of simulated use

Copper has well-documented antibacterial effects but few have evaluated it after prolonged use and against bacteria and viruses. Coupons from three copper formulations (solid, thermal coating, and decal applications) and carbon steel controls were subjected to 200 rounds simulated cleaning using a Wiperator™ and either an accelerated hydrogen peroxide, quaternary ammonium, or artificial sweat products. Antibacterial activity against S. aureus and P. aeruginosa was then evaluated using a modified Environmental Protection Agency protocol. Antiviral activity against coronavirus (229E) and norovirus (MNV-1) surrogates was assessed using the TCID50 method. Results were compared to untreated control coupons. One hour after inoculation, S. aureus exhibited a difference in log kill of 1.16 to 4.87 and P. aeruginosa a log kill difference of 3.39–5.23 (dependent upon copper product and disinfectant) compared to carbon steel. MNV-1 demonstrated an 87–99% reduction on each copper surfaces at 1 h and 99% reduction at 2 h compared to carbon steel. Similarly, coronavirus 229E exhibited a 97–99% reduction after 1 h and 90–99% after 2 h. Simulated use with artificial sweat did not hinder the antiviral nor the antibacterial activity of Cu surfaces. Self-sanitizing copper surfaces maintained antibacterial and antiviral activity after 200 rounds of simulated cleaning. Graphical abstract

Efficacy of microbicidal actives and formulations for inactivation of Lassa virus in suspension

The World Health Organization’s R&D Blueprint list of priority diseases for 2022 includes Lassa fever, signifying the need for research and development in emergency contexts. This disease is caused by the arenavirus Lassa virus (LASV). Being an enveloped virus, LASV should be susceptible to a variety of microbicidal actives, although empirical data to support this expectation are needed. We evaluated the virucidal efficacy of sodium hypochlorite, ethanol, a formulated dual quaternary ammonium compound, an accelerated hydrogen peroxide formulation, and a p-chloro-m-xylenol formulation, per ASTM E1052-20, against LASV engineered to express green fluorescent protein (GFP). A 10-μL volume of virus in tripartite soil (bovine serum albumin, tryptone, and mucin) was combined with 50 μL of disinfectant in suspension for 0.5, 1, 5, or 10 min at 20–25 °C. Neutralized test mixtures were quantified by GFP expression to determine log10 reduction. Remaining material was passaged on Vero cells to confirm absence of residual infectious virus. Input virus titers of 6.6–8.0 log10 per assay were completely inactivated by each disinfectant within 1–5 min contact time. The rapid and substantial inactivation of LASV suggests the utility of these microbicides for mitigating spread of infectious virus during Lassa fever outbreaks.

Efficacy of high-level disinfection of endoscopes contaminated with Streptococcus equi subspecies equi with 2 different disinfectants.

Prevention of spread of Streptococcus equi subspecies equi (S. equi) after an outbreak is best accomplished by endoscopic lavage of the guttural pouch, with samples tested by culture and real time, quantitative polymerase chain reaction (qPCR). Disinfection of endoscopes must eliminate bacteria and DNA to avoid false diagnosis of carrier horses of S. equi. Compare failure rates of disinfection of endoscopes contaminated with S. equi using 2 disinfectants (accelerated hydrogen peroxide [AHP] or ortho-phthalaldehyde [OPA]). The null hypothesis was that there would be no difference between the AHP and OPA products (based on culture and qPCR results) after disinfection. Endoscopes contaminated with S. equi were disinfected using AHP, OPA or water (control). Samples were collected before and after disinfection and submitted for detection of S. equi by culture and qPCR. Using a multivariable logistic regression model-adjusted probability, with endoscope and day as controlled variables, the probability of an endoscope being qPCR-positive was determined. After disinfection, all endoscopes were culture-negative (0%). However, the raw unadjusted qPCR data were positive for 33% AHP, 73% OPA, and 71% control samples. The model-adjusted probability of being qPCR-positive after AHP disinfection was lower (0.31; 95% confidence interval [CI], -0.03-0.64) compared to OPA (0.81; 95% CI, 0.55-1.06), and control (0.72; 95% CI, 0.41-1.04). Disinfection using the AHP product resulted in significantly lower probability of endoscopes being qPCR-positive compared to the OPA product and control.

Cost minimization analysis of nasopharyngoscope reprocessing in community practice

BackgroundReprocessing of nasopharyngoscopes represents a large financial burden to community physicians. The aim of this study was to perform a cost analysis of nasopharyngoscope reprocessing methods at the community level.MethodsElectronic surveys were distributed by email to community otolaryngologists. Surveys were comprised of 14 questions assessing clinic size, nasopharyngoscope volume, scope reprocessing method and maintenance. Four manual techniques were evaluated: (1) soak with ortho-phthalaldehyde solution (Cidex-OPA; Advanced Sterilization Products, Johnson and Johnson Inc., Markham, Canada), (2) soak with accelerated hydrogen peroxide solution (Revital-Ox; Steris Canada Inc., Mississauga, Canada), (3) disinfection with chlorine dioxide wipe (Tristel Trio Wipes System; Tristel plc., Cambridgeshire, UK), (4) UV-C light system (UV Smart, Delft, The Netherlands). All costs are reported in CAD, and consumable and capital costs for reprocessing methods were obtained from reported vendor prices. Time costs were derived from manufacturer recommendations, the Ontario Medical Association Physician’s Guide to Uninsured Services, and the Ontario Nurses Association Collective Agreement. Cost analyses determined the most cost-effective reprocessing method in the community setting. Sensitivity analyses assessed the impact of reprocessing volume and labour costs.ResultsThirty-six (86%) otolaryngologists responded and answered the survey. The cost per reprocessing event for Cidex-OPA, Revital-Ox, Tristel and UV system were $38.59, $26.47, $30.53, and $22.74 respectively when physicians reprocessed their endoscopes themselves. Sensitivity analyses demonstrated that Revital-Ox was the least costly option in a low volume, however, the UV system remained the most cost effective in higher volumes. The cost per reprocessing event when done by clinic staff was $5.51, $4.42, $11.23 and $6.21 for Cidex-OPA, Revital-Ox, Tristel and the UV system.ConclusionsThe UV light system appears to be the most cost-effective method in high volumes of reprocessing, and Revital-Ox is cheaper in lower volumes and when performed by clinic staff rather than physicians. It is important to consider the anticipated work volume, shared clinic space and number of co-workers prior to choosing a reprocessing method.Graphical

Efficacy of hydrogen peroxide wipes for decontamination of AZD1222 adenovirus COVID-19 vaccine strain on pharmaceutical industry materials.

This study aimed to evaluate the performance of accelerated hydrogen peroxide® wipes (HPW) for decontamination of the chimpanzee adenovirus AZD1222 vaccine strain used in the production of recombinant COVID‐19 vaccine in a pharmaceutical industry. Two matrices were tested on stainless‐steel (SS) and low‐density‐polyethylene (LDP) surfaces: formulated recombinant COVID‐19 vaccine (FCV) and active pharmaceutical ingredient (API). The samples were spiked, dried and the initial inoculum, possible residue effect (RE) and titre reduction after disinfection with HPW were determined. No RE was observed. The disinfection procedure with HPW resulted in complete decontamination the of AZD1222 adenovirus strain in FCV (≥7·46 and ≥7·49 log10 infectious unit [IFU] ml−1 for SS and LDP carriers respectively) and API (≥8·79 and ≥8·78 log10 IFU ml−1 for SS and LDP carriers respectively). In conclusion, virucidal activity of HPW was satisfactory against the AZD1222 adenovirus strain and can be a good option for disinfection processes of SS and LPD surfaces in pharmaceutical industry facilities during recombinant COVID‐19 vaccine production. This procedure is simple and can be also applied on safety unit cabins and sampling bags made of LDP as well.

Feline Panleukopenia Infections : Treatment and Control in Nepal

Feline panleukopenia is a fatal and contagious viral disease caused by the family of Parvoviridae. Feline panleukopenia virus (FPV) is synonymously called as feline distemper and feline Parvo. FPV infects all felids, raccoons, mink and foxes. FPV infected animals generally have compromised health conditions. Cats of all ages are mostly affected by FPV, but kittens are highly susceptible with higher mortality. The virus is resistant to many disinfectants and normally survives in the environment for several months. Transmission occurs through direct contact of faeces contaminated feeds as well as by indirect contact of fomites, and through intrauterine route. Clinical symptoms include vomition, diarrhoea, lymphopenia and neutropenia, followed by thrombocytopenia and anaemia, immunosuppression, cerebellar ataxia and abortion. Commercially available test kits are used to detect FPV antigen in faeces. Fluid therapy, antibiotics, metronidazole, supportive therapy, and good nursing care are the common treatment practice in Central Referral Veterinary Hospital (CRVH), Nepal. The disease can be controlled by isolation of infected cats, routine vaccination and disinfection of premises. The higher incidence in Nepal is due to lack of vaccination practice against FPV. Disinfectants containing sodium hypochlorite (bleach), potassium peroxymonosulfate and accelerated hydrogen peroxide are found effective. The aim of this paper is to review the current status of the disease, epidemiology, pathophysiology, diagnosis, treatment and control measures for prevention and management of feline panleukopenia infections in developing countries like Nepal.

Disinfection and conditions associated with thermo-assisted drying and decontamination inconsistently produce negative PRRSV rRT-PCR results on metal surfaces

Because contaminated livestock trailers are a significant risk for transmitting viruses between herds, various methods of washing, disinfecting, and thermo-assisted drying and decontamination (TADD) have been evaluated for their effectiveness in inactivating porcine reproductive and respiratory syndrome virus (PRRSV) on contaminated surfaces. Information on when to expect negative qRT-PCR results after adequate trailer sanitation is lacking. The objective of this study was to evaluate whether there are conditions associated with washing-disinfectant-TADD procedures that will consistently produce a negative qRT-PCR result for the purpose of monitoring compliance with trailer sanitation and decontamination protocols for PRRSV on metal surfaces. 144 diamond plate aluminum coupons were spiked with PRRSV or phosphate-buffered saline (PBS) and treated with a designated disinfectant protocol. Disinfectants evaluated included multiple accelerated® hydrogen peroxide (AHP) disinfectants and a quaternary ammonium and glutaraldehyde combination disinfectant. Disinfectant was applied for 5 or 60 minutes of contact time at either 20 °C or −10 °C in a matrix of feces or PBS. All coupons were heated until the surface temperature of the coupon reached 71 °C and then held for 10 minutes to simulate TADD under field conditions. Post-treatment swabs for all treatment groups, except negative control groups, were positive by PRRSV qRT-PCR. Under the conditions evaluated in this study, consistently negative qRT-PCR results after treatments were not found. Therefore, for the purpose of monitoring compliance with trailer sanitation and decontamination protocols for PRRSV, alternatives to qRT-PCR should be explored.

Pre-eminence and comparative analysis of skin and surface disinfectants: A systematic review to pave the way for SARS-CoV-2 prevention

More than 200 countries have been devastated by the SARS-CoV-2 pandemic. The health workers exposed to SARS patients have been confirmed to be infected with coronavirus (SARS-CoV-2), regardless of the degree of their exposure. The increasing complexity of virus existence and heterogeneity has cast doubt on disinfectants as a viable choice. Hence, the present systematic review aims to achieve the comparative analysis of established disinfectants against enveloped and non-enveloped viruses including SARS-CoV and MERS-CoV. Three databases (Pubmed, Google scholar, and Medline) were searched to frame the systematic review. Our comparative analyses with 34 studies have found that 85% ethanol-based hand sanitizers and 7.5% Povidine Iodine based soaps/surgical scrub could be used to deter the SARS-CoV-2 virus as preferred hand sanitizers. For surface eradication, 0.5% sodium hypochlorite or a mixture of glutaraldehyde, Quaternary Ammonium Compounds (QAC), and isopropanol could have more efficacies as compared to hydrogen peroxide, phenol, and QAC alone. Moreover, the accelerated hydrogen peroxide as an active ingredient in the automatic quick surface disinfectant (tunnel system), maybe a positive indication for quick whole-body sanitation. Additionally, the alternative method for avoiding the rapidly increasing chain of infection with SARS and restarting regular life has been exclusively discussed.

Evaluation of the Use of Sea Water as a Diluent for an Accelerated Hydrogen Peroxide Disinfectant for Inactivation of Avian Influenza Virus: A Surrogate for Infectious Salmon Anemia Virus.

Introduction: Use of sea water as a diluent for disinfectants has been of practical interest for control of aquaculture disease outbreaks in sea where fresh water is limited. This study evaluated the use of natural sea water (NSW), artificial sea water (ASW), or standard hard water (SHW) as a diluent for preparation of accelerated hydrogen peroxide (AHP) solutions against an avian influenza virus, a surrogate for the infectious salmon anemia virus. Methods: AHP solutions containing 0.18%, 0.35%, or 0.44% (w/w) of hydrogen peroxide (H2O2), corresponding to 1/40, 1/20, and 1/16 dilutions of the disinfectant concentrate, were evaluated at -20°C, 4°C, and 21°C. Results: When NSW was used as the diluent, a 0.35% H2O2 concentration was required to inactivate ∼6 log10 virus at 21°C in a 5-min contact time. When temperature dropped to 4°C, 0.44% H2O2 in NSW was required to obtain a similar inactivation within a 5-min contact time. At -20°C, supplemented with antifreeze agents, the 0.44% H2O2 in NSW solutions produced complete inactivation of 5.4 log10 virus within a 10-min contact time. In comparison, lower H2O2 concentrations and/or shorter contact times were needed to inactivate equal amounts of the virus at the same temperature when using SHW or ASW as a diluent to prepare disinfection solutions. Conclusion: The results suggested that NSW could be used as a diluent in disinfection solutions for virus inactivation as long as disinfectant concentrations and/or contact times are properly increased.

Efficacy of three disinfectant formulations and a hydrogen peroxide/silver fogging system on surfaces experimentally inoculated with meticillin-resistant Staphylococcus pseudintermedius.

Effective environmental disinfection is necessary to prevent nosocomial infections from meticillin-resistant Staphylococcus pseudintermedius (MRSP). However, there are currently no commercial disinfectant sprays or fogging systems with label claims against MRSP. To evaluate the efficacy of a quaternary ammonium product (QAC), an accelerated hydrogen peroxide product (AHP), a hydrogen peroxide and silver product (HAL), and a hydrogen peroxide and silver fogging system (FOG) against MRSP. Sterile plastic surfaces inoculated with MRSP were treated with 200µL of QAC, AHP or HAL for the recommended contact times. For FOG, inoculated samples were placed in eight positions within a sealed room before fogging for the recommended contact time. Post-treatment bacterial counts were compared to untreated positive controls. Sterile uninoculated surfaces served as negative controls. Least-squares mean reduction (log10 ) in colony forming units (cfu) was 3.55 log10 for QAC (P<0.0001), 3.60 log10 for AHP (P<0.0001), 1.66 log10 for HAL (P<0.0001) and 0.32 log10 for FOG (P=0.004). QAC, AHP and HAL reduced MRSP cfu by 99.97%, 99.98% and 97.81%, respectively. FOG reduced cfu by 52.14%. QAC and AHP effectively disinfected surfaces inoculated with MRSP. Although HAL provided lower MRSP reduction, it may be considered clinically acceptable. FOG as a sole means of MRSP disinfection was not supported yet may have utility as an adjunctive disinfectant in clinical areas with bacterial densities lower than our experimental inoculum.

In vitro evaluation of antimicrobial efficacy and durability of three copper surfaces used in healthcare.

Antimicrobial properties of solid copper (Cu) surfaces against various microorganisms have been demonstrated, but little is known about the durability and relative antimicrobial efficacy of different Cu formulations currently used in healthcare. The aim of this study was to assess whether three different formulations of copper-bearing alloys (integral, spray-on and Cu-impregnated surfaces) and a stainless steel control differed in their antimicrobial efficacy, durability, and compatibility with hospital-grade cleaner/disinfectants. The U.S. Environmental Protection Agency draft protocol for the evaluation of bactericidal activity of Cu containing alloys was modified to more accurately reflect cleaning methods in healthcare. The three different Cu alloys were evaluated using 25 × 25 × 3 mm disks subjected to one year of simulated cleaning and disinfection using the Wiperator™ with microfiber cloths presoaked in three common hospital disinfectants: accelerated hydrogen peroxide, quaternary ammonium, or sodium hypochlorite solutions. Bactericidal activity was evaluated using Staphylococcus aureus and Pseudomonas aeruginosa. While all Cu formulations exhibited some antimicrobial activity, integral and spray-on Cu alloys showed the greatest efficacy. Assessments of durability included documentation of changes in mass, morphological changes by scanning electron microscopy, chemical composition alteration by energy-dispersive x-ray spectroscopy, and surface roughness alteration using profilometry over one year of simulated use. The integral Cu alloy had the least mass loss (0.20% and 0.19%) and abrasion-corrosion rate (6.28 and 6.09 μm/yr) compared to stainless steel. The integral product also showed the highest durability. Exposure to disinfectants affected both the antimicrobial efficacy and durability of the various copper products.

Decontamination of 70 foster family homes exposed to Microsporum canis infected cats: a retrospective study

Dermatophytosis is a superficial fungal skin disease of animals. A key part of treatment is cleaning and disinfection of the environment to prevent false-positive results due to fomite carriage. Furthermore, there is a perception in the lay literature that decontamination of homes is difficult or impossible. Data from a 10year period identified 70 foster family homes where Microsporum canis infected cats had lived for varying periods of time. Mechanical debris was removed from the rooms housing the cats, the areas cleaned with over-the-counter household detergents, rinsed and hard surfaces disinfected with 1:100 concentration household bleach or accelerated hydrogen peroxide. Thirty-eight homes were completely decontaminated after one cleaning post removal or cure of the cat. Of the remaining homes, decontaminated was achieved after one (n=28), two (n=2) or three (n=1) additional cleanings. Complete decontamination was not possible in one home; the foster family was admittedly noncompliant. There was no evidence of disease transmission to other animals or people. Environmental decontamination is not difficult in homes exposed to M.canis and can be accomplished with established procedures.

Evaluation of an accelerated hydrogen peroxide disinfectant to inactivate porcine epidemic diarrhea virus in swine feces on aluminum surfaces under freezing conditions

BackgroundSince its emergence in 2013, porcine epidemic diarrhea virus (PEDV) spread rapidly throughout the country due, in part, to contaminated livestock trailers. The objective of this study was to test the efficacy of an accelerated hydrogen peroxide (AHP) disinfectant for inactivating PEDV in swine feces on metal surfaces under freezing conditions. One 15.24 X 15.24 X 2.54 cm aluminum coupon, contaminated with swine feces, and randomly matched to one pig was the experimental unit. Eight treatment groups representing two AHP concentrations (1:16 and 1:32) in a 10% propylene glycol solution, two contact times in a -10 °C freezer (40 min and 60 min), and two levels of fecal contamination (5 mL and 10 mL) in addition to negative and positive control groups were evaluated. Forty 3-week-old pigs, intragastrically inoculated with the contents of the coupons after treatment, were used as a bioassay to determine the infectivity of PEDV after treatment. Infectivity was determined by detection of virus with a nucleocapsid (N) gene-based quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) on rectal swabs collected from the inoculated pigs on days three and seven post-inoculation.ResultsAll post-treatment swabs from the negative control coupons were negative for PEDV via RT-qPCR. All post-treatment swabs collected from coupons in the AHP disinfectant treatment groups and the positive control group were positive for PEDV via RT-qPCR. For the bioassay, no rectal swabs from pigs in the negative control (0 of 4) or the AHP disinfectant treatment groups (0 of 32) were positive for PEDV. Rectal swabs from all pigs within the positive control group (4 of 4) were positive for PEDV by RT-qPCR.ConclusionsUnder the conditions of this study, 1:16 and 1:32 dilutions of the AHP disinfectant successfully inactivated PEDV in swine feces on metal surfaces when applied at -10 °C with 40 or 60 min of contact time. This study also suggests that a positive RT-qPCR result for PEDV on an environmental sample should be expected when the AHP disinfectant is applied under freezing conditions, but does not necessarily indicate that an infectious dose of PEDV remains after disinfection.

Effects of contact time and concentration on bactericidal efficacy of 3 disinfectants on hard nonporous surfaces

This study investigated the influence of contact time and concentration on bactericidal efficacy of 3 types of disinfectants (accelerated hydrogen peroxide [AHP], quaternary ammonium compounds [Quats], and sodium hypochlorite) on stainless steel surfaces using Environmental Protection Agency procedure MB-25-02. We found that bactericidal efficacy was not reduced at contact times or concentrations immediate lower than label use values, but all 3 disinfectants were significantly less bactericidal at significantly lower than label use contact times and concentrations. Overall, the bactericidal efficacy of the sodium hypochlorite disinfectant was most tolerant to the decreases of contact times and concentrations, followed closely by AHP disinfectant, and Quat disinfectant was most affected by contact time and concentration.

In vitro efficacy of shampoos containing miconazole, ketoconazole, climbazole or accelerated hydrogen peroxide against Microsporum canis and Trichophyton species.

Objectives The objective was to evaluate the antifungal efficacy of shampoo formulations of ketoconazole, miconazole or climbazole and accelerated hydrogen peroxide wash/rinse against Microsporum canis and Trichophyton species spores. Methods Lime sulfur (1:16)-treated control, enilconazole (1:100)-treated control, accelerated hydrogen peroxide (AHP 7%) 1:20 and a 1:10 dilution of shampoo formulations of miconazole 2%, miconazole 2%/chlorhexidine gluconate 2-2.3%, ketoconazole 1%/chlorhexidine 2%, climbazole 0.5%/chlorhexidine 3% and sterile water-untreated control were tested in three experiments. In the first, a suspension of infective spores and hair/scale fragments was incubated with a 1:10, 1:5 and 1:1 dilution of spores to test solutions for 10 mins. In the second, toothbrushes containing infected cat hair in the bristles were soaked and agitated in test solutions for 10 mins, rinsed, dried and then fungal cultured (n = 12×). In the third, a 3 min contact time combined with an AHP rinse was tested (n = 10×). Good efficacy was defined as no growth. Results Water controls grew >300 colony-forming units/plate and all toothbrushes were culture-positive prior to testing. For the suspension tests, all test products showed good efficacy. Miconazole 2%, ketoconazole 1% and AHP showed good efficacy after a 10 min contact time. Good efficacy was achieved with a shorter contact time (3 mins) only if combined with an AHP rinse. Conclusions and relevance Lime sulfur and enilconazole continued to show good efficacy. In countries or situations where these products cannot be used, shampoos containing ketoconazole, miconazole or climbazole are alternative haircoat disinfectants, with a 10 min contact time or 3 mins if combined with an AHP rinse.

A new buildup biofilm model that mimics accumulation of material in flexible endoscope channels

The objective of this study was to develop a new build up biofilm (BBF) model that was based on repeated exposure to test soil containing Enterococcus faecalis and Pseudomonas aeruginosa and repeated rounds of fixation to mimic the accumulation of patient material in endoscope channels during reprocessing. The new BBF model is a novel adaptation of the minimum biofilm effective concentration (MBEC) 96-well model where biofilm is formed on plastic pegs. The new MBEC-BBF model was developed over eight days and included four rounds of partial fixation using glutaraldehyde. There was 6.14Log10cfu/cm2 of E. faecalis and 7.71Log10cfu/cm2 of P. aeruginosa in the final BBF. Four detergents (two enzymatic and two non-enzymatic) were tested alone or in combination with orthophthalaldehyde, glutaraldehyde or accelerated hydrogen peroxide to determine if BBF could be either removed or the bacteria within the BBF killed. None of the detergents alone could remove the biofilm or reduce the bacterial level in the BBF as determined by viable count and scanning electron microscopy. The combination of detergents and disinfectants tested provided a 3 to 5Log10 reduction in viable bacteria but no combination could provide the expected 6Log10 reduction. Our data indicated that once formed BBF was extremely difficult to eliminate. Future research using the BBF model may help develop new cleaning and disinfection methods that can prevent or eliminate BBF within endoscope channels.

Evaluation of the ability of different detergents and disinfectants to remove and kill organisms in traditional biofilm.

The objective of this study was to assess the ability of different detergent and disinfectant combinations to eradicate bacteria in traditional biofilm. Enterococcus faecalis and Pseudomonas aeruginosa were used to develop biofilm over 8 days. The biofilm on each minimum biofilm eradication concentration peg contained 8 log10 colony forming units (CFU)/cm2 of both bacteria. The detergents evaluated were as follows: Prolystica Enzymatic 2X, Prolystica Neutral 2X, Neodisher, and Endozime Bio-Clean. The disinfectants evaluated were as follows: glutaraldehyde, accelerated hydrogen peroxide, and ortho-phthalaldehyde. Biofilm removal was evaluated using viable count, protein and carbohydrate quantitation, and scanning electron microscopy. Only Prolystica Enzymatic 2X and Endozime Bio-Clean killed both E faecalis (3.90 log10 CFU/mL reduction) and P aeruginosa (3.96 log10 CFU/mL reduction) in suspension. None of the detergents tested could provide >1 log10 CFU/cm2 reduction for bacteria within biofilm. Any combination of detergent and high-level disinfectant reduced the level of both E faecalis and P aeruginosa within biofilm by 3-5 log10 CFU/cm2. Although the combination of Endozime Bio-Clean and glutaraldehyde provided a 6 log10 reduction, it could not eliminate both bacteria within biofilm. Our data indicate that if biofilm accumulates in flexible endoscope channels during repeated rounds of reprocessing, then neither the detergent nor high-level disinfectant will provide the expected level of bacterial removal or killing.

Evaluation of disinfection protocols to reduce virus transmission via livestock transport vehicles using model trailers and experimental conditions

Objective: To determine the efficacy of accelerated hydrogen peroxide disinfectant and combined glutaraldehyde and quaternary ammonium disinfectant after a high-pressure wash against porcine reproductive and respiratory syndrome virus (PRRSV) and transmissible gastroenteritis virus (TGEV) in experimental settings mimicking field conditions commonly experienced on livestock trailers. Materials and methods: Aluminum model livestock trailers (1:61) were contaminated with PRRSV- and TGEV-spiked feces. Each model trailer underwent a simple washing procedure and an assigned disinfectant application. Four environmental swabs were collected per trailer at five time points and tested by PRRSV quantitative polymerase chain reaction (qPCR) and TGEV polymerase chain reaction (PCR). Ten-week old pigs were inoculated orally and intramuscularly with supernatant from environmental samples taken from model trailers at two time points after disinfection. Fecal swabs and blood collected at 7 and 14 days post inoculation were tested by PRRSV qPCR and TGEV PCR to determine if the inoculum had contained live infectious virus. Results: All Positive Control pigs were positive by PRRSV qPCR at 7 and 14 days post inoculation and by PRRSV enzyme-linked immunosorbent assay (ELISA) at day 14. Pigs in the other treatment groups were negative by PRRSV qPCR and PRRSV ELISA at all time points. Results of TGEV testing were inconclusive because the Positive Control group failed to become infected. Implication: Under study conditions, a high-pressure wash with cold water plus application of an accelerated hydrogen peroxide or a combined glutaraldehyde and quaternary ammonium disinfectant is effective at inactivating PRRSV.