Hypochlorous Acid Research by Microbe - Results Type: Bacteria Microbe: Pseudomonas

Many antiseptics have been used to treat wounds. To compare the microbicidal efficacy of ClHO (Clortech) with other antiseptics used on wounds, healthy skin and mucous membranes. The microbicidal efficacy of 13 antiseptic products on eight micro-organisms (three Gram-positive three Gram-negative two yeasts) inoculated on organic germ-carriers was studied. In addition, the loss of efficacy against Staphylococcus aureus and Pseudomonas aeruginosa with biofilm was assessed with the six best-performing products. Chlorhexidine (1) had the highest microbicidal effect at 1 min. At 5 min, 500 and 1500 mg/L ClHO showed similar, or better, activity than the other antiseptics studied. The ClHO concentration of 300 mg/L achieved this same efficacy at 10 min. The product that lost the most efficacy due to biofilm was 1 chlorhexidine, while 1 PVP-I and ClHO at either 300 or 500 mg/L were moderately affected by biofilm. The most effective in the presence of biofilm was ClHO at 1500 mg/L. ClHO at mediumlow concentrations (300 or 500 mg/L) is a good antiseptic that can be used on wounds and mucous membranes for 510 min. Lower concentrations of ClHO, as well as of the other antiseptics studied, were less effective or more altered by the biofilm. ClHO at a concentration of 1500 mg/L is very effective in the presence or absence of biofilm that can be used on healthy skin for 5 min.

Weakly acidic hypochlorous acid (HClO 200 ppm, pH 6.5) is effective against a broad range of microorganisms. We have previously reported a study of developing antimicrobial biomaterials made up of chitin-nanofiber sheet (CNFS) -immobilized silver nanoparticles (CNFS/Ag NPs) and showed that either cleansing with HClO or covering with CNFS/Ag NPs daily for more than 7 days resulted in delayed wound healing. This study aimed to evaluate disinfection and wound healing by a combination of cleansing with HClO and covering with CNFS/Ag NPs daily for 3 days. Applying HClO CNFS/Ag NPs daily for 3 days and then cleansing with just pure water and covering with CNFS alone daily for 9 days were performed for Pseudomonas aeruginosa-infected wounds in db/db diabetic mice. We found a significant enhancement of wound healing and a reduction of bacteria counts compared to the controls. Histological examination showed significantly advanced granulation tissue and capillary formations in the wounds on Day 12. These results suggest that limited disinfection to 3 days with HClO CNFS/Ag NPs may be sufficient to avoid negative effects on wound repair.

Biofilm formation causes prolonged wound infections due to the dense biofilm structure, differential gene regulation to combat stress, and production of extracellular polymeric substances. Acinetobacter baumannii, Staphylococcus aureus, and Pseudomonas aeruginosa are three difficult-to-treat biofilm-forming bacteria frequently found in wound infections. This work describes a novel wound dressing in the form of an electrochemical scaffold (e-scaffold) that generates controlled, low concentrations of hypochlorous acid (HOCl) suitable for killing biofilm communities without substantially damaging host tissue. Production of HOCl near the e-scaffold surface was verified by measuring its concentration using needle-type microelectrodes. E-scaffolds producing 17, 10 and 7mM HOCl completely eradicated S. aureus, A. baumannii, and P. aeruginosa biofilms after 3hours, 2hours, and 1hour, respectively. Cytotoxicity and histopathological assessment showed no discernible harm to host tissues when e-scaffolds were applied to explant biofilms. The described strategy may provide a novel antibiotic-free strategy for treating persistent biofilm-associated infections, such as wound infections.

Sodium hypochlorite (NaClO, SHC)/hypochlorous acid (HClO, HCA) wound irrigation solutions have experienced a renaissance in the prevention and treatment of low-level wound infections. They are attributed with lower cytotoxicity and have therefore gained increasing attention in daily clinical practice. To determine the cytotoxicity and antimicrobial efficacy of six NaClO/HClO wound irrigation solutions. For cytotoxicity evaluation (based on DIN EN 10993-5), human keratinocytes (HaCaT) and human skin fibroblasts (BJ) were used. Staphylococcus aureus and Pseudomonas aeruginosa were used for antimicrobial efficacy evaluation (based on DIN EN 13727). Solutions were evaluated after 1, 5 and 15min of exposure. Additionally, physicochemical properties (pH and oxidationreduction potential values) were investigated. Efficacy and cytotoxicity varied significantly between solutions. Generally, increasing antimicrobial activity was associated with decreasing cell viability. Furthermore, a concentration- and time-dependent impact on pathogens and cells was observed: cytotoxic and antimicrobial activity increased with rising NaClO/HClO solution concentrations and extended exposure times. Based on these in vitro evaluations, the following ranking (lowest to highest microbicidal effect and cytotoxic impact) was found: Microdacyn60 (SHC/HCA-M)

In-vitro and in-vivo studies have supported antimicrobial, anti-inflammatory, and other biologic properties of hypochlorous acid (HOCl), which has led to its in the treatment of skin wounds, pruritus, diabetic ulcers, and some inflammatory skin disorders. Research has also shown that the physiochemical properties of HOCl after application to skin are highly dependent on both pH and formulation stability. In this review, the authors discuss a core HOCI formulation that is stable for up to two years, noncytotoxic, and pH-neutralized to augment therapeutic activity, skin tolerability, and stability. The authors summarize relevant study outcomes and potential modes of action related to this core HOCI formulation, as well as describe its ready-to-vehicles that are approved and available for topical application.

The purpose of this study was to determine whether a commercial formulation of hypochlorous acid hygiene solution (0.01), Avenova, can destroy existing biofilms formed by ocular clinical bacterial isolates, including blepharitis isolates of Staphylococcus aureus and coagulase-negative staphylococci (CNS), and a keratitis isolate of Pseudomonas aeruginosa. Biofilms grown in bacterial growth media on disposable contact lens cases were challenged with hypochlorous acid hygiene solution. At various time points, surviving bacteria were quantified by serial dilution and colony counts. S. aureus biofilms formed on glass were challenged using a hypochlorous acid hygiene solution, and imaged using vital staining and confocal laser scanning microscopy. Bactericidal activity (3 Log10 99.9) was observed for all tested bacterial species after a 30-minute exposure. S. aureus biofilms had a bactericidal level of killing by 10 minutes (p<0.01), S. capitis by 5 minutes (p<0.001), S. epidermidis by 30 minutes (p<0.001), and P. aeruginosa by 10 minutes (p<0.01). Confocal microscopy and crystal violet staining analysis of bacterial biofilms treated with hypochlorous acid solution both demonstrated that biofilm bacteria were readily killed, but biofilm structure was largely maintained. Hypochlorous acid (0.01) hygiene solution was able to achieve bactericidal levels of killing of bacteria in biofilms, but did not disrupt biofilm structures. Susceptibility of tested staphylococcal blepharitis isolates varied by species, with S. capitis being the most susceptible and S. epidermidis being the least susceptible.

The bacterial species and specific spoilage organisms associated with the Southern Australian King George Whiting (KGW) and Tasmanian Atlantic Salmon (TAS), and the efficacy of a HOCl-containing water-based sanitization product (Electro-Chemically Activated Solution, by ECAS4) in extending the shelf life of KGW and TAS fillets were evaluated. Fillets were washed with an ECAS4 solution containing either 45 ppm or 150 ppm of free chlorine and bacterial species enumerated on out many of the disadvantages of currently approved biocides.

In the dairy industry, cleaning and disinfection of surfaces are important issues and development of innovative strategies may improve food safety. This study was aimed to optimize the combined effect of alkaline electrolyzed water (AEW) and neutral electrolyzed water (NEW) as s were significantly affected by surface roughness electropolished SSP required 10 min, 100 mg/L AEW at 30 C, whereas SSP without modification required 30 min, 300 mg/L AEW at 30 C. From confirmatory tests cells removed were 3.90 0.25 log CFU/cm2 for electropolished SSP, and 3.20 0.20 log CFU/cm2 for SSP without modification. NEW is non-corrosive, and can be advantageously used for environmentally friendly cleaning and disinfection processes.

The efficacy of thin-film diamond coated electrodes (DiaCell 101) for disinfection of water artificially contaminated with Penicillium digitatum and Pseudomonas spp. was tested. Electrolysis process was performed with different operation conditions: current densities at 4, 8, and 12A and water flow rate at 150, 300, and 600 L/h. For both pathogens, the experiments were performed in water suspensions at a final concentration of 105 CFU/ml. Tap water was used as a control. The results showed that fungal spores and bacterial cells were affected by flow rate and current density applied. The higher the water flow rate the greater the inactivation of the two microorganisms which were completely suppressed at high recirculation flow (300-600 L/h/cell). Pseudomonas spp. cells were inactivated at the highest current density applied (8-12A) after 6 min of electrolysis, whereas for P. digitatum the complete inactivation was observed at the same current densities after 12 min. The results obtained suggest that the two parameters can be modulated in order to achieve significant suppression in relation to the target microorganism and to obtain an antimicrobial effect without generation of chlorine.

The aim of this study was to investigate the in-vitro antimicrobial activity of usage and normal concentrations of electrolyzed water in hospital. In our study, the effects of different concentrations of electrolyzed water on two gram positive, four gram negative standard strains and clinical isolates of four gram negative, two gram positive, one spore-forming bacillus and Myroides spp strains that lead to hospital infections were researched. The effects of different concentrations and different contact times of Envirolyte electrolyzed water on cited strains were researched through method of qualitative suspension tests. Petri dishes fo bacteria have been incubated at 37 C 48 hours. Bactericidal disinfectant was interpreted to be effective at the end of the period due to the lack of growth. Solutions to which disinfectant were not added were prepared with an eye to control reproduction and controlcultures were made by using neutralizing agents. 1/1, 1/2, and 1/10 concentrations of Envirolyte electrolyzed water were found to be effective on the bacteria that lead to hospital infections used during all test times. As a conclusion, based upon the results we acquired, it was observed that Envirolyte electrolyzed water of 100 concentration would be convenient to be used for disinfection when diluted to a usage concentration of 1/10.

In the present study, we evaluated the antimicrobial activity of neutral electrolyzed water (NEW) against 14 strains of spoilage Pseudomonas of fresh cut vegetables under cold storage. The NEW, produced from solutions of potassium and sodium chloride, and sodium bicarbonate developed up to 4000 mg/L of free chlorine, depending on the salt and relative concentration used. The antimicrobial effect of the NEW was evaluated against different bacterial strains at 105 cells/ml, with different combinations of free chlorine concentration/contact time; all concentrations above 100 mg/L, regardless of the salt used, were found to be bactericidal already after 2 min. When catalogna chicory and lettuce leaves were dipped for 5 min in diluted NEW, microbial loads of mesophilic bacteria and Enterobacteriaceae were reduced on average of 1.7 log cfu/g. In addition, when lettuce leaves were dipped in a cellular suspension of the spoiler Pseudomonas chicorii I3C strain, diluted NEW was able to reduce Pseudomonas population of about 1.0 log cfu/g. Thanks to its high antimicrobial activity against spoilage microorganisms, and low cost of operation, the application of cycles of electrolysis to the washing water looks as an effective tool in controlling fresh cut vegetable microbial spoilage contamination occurring during washing steps.

This study evaluated the efficacy of individual treatments (thermosonication [TS+DW] and slightly acidic electrolyzed water [SAcEW]) and their combination on reducing Escherichia coli O157:H7, Listeria monocytogenes, and spoilage microorganisms (total bacterial counts [TBC], Enterobacteriaceae, Pseudomonas spp., and yeast and mold counts [YMC]) on fresh-cut kale. For comparison, the antimicrobial efficacies of sodium chlorite (SC; 100 mg/L) and sodium hypochlorite (SH; 100 mg/L) were also evaluated. Each 10 g sample of kale leaves was inoculated to contain approximately 6 log CFU/g of E. coli O157:H7 or L. monocytogenes. Each inoculated or uninoculated samples was then dip treated with deionized water (DW; control), TS+DW, and SAcEW at various treatment conditions (temperature, physicochemical properties, and time) to assess the efficacy of each individual treatment. The efficacy of TS+DW or SAcEW was enhanced at 40 C for 3 min, with an acoustic energy density of 400 W/L for TS+DW and available chlorine concentration of 5 mg/L for SAcEW. At 40 C for 3 min, combined treatment of thermosonication 400 W/L and SAcEW 5 mg/L (TS+SAcEW) was more effective in reducing microorganisms compared to the individual treatments (SAcEW, SC, SH, and TS+DW) and combined treatments (TS+SC and TS+SH), which significantly (P < 0.05) reduced E. coli O157:H7, L. monocytogenes, TBC, Enterobacteriaceae, Pseudomonas spp., and YMC by 3.32, 3.11, 3.97, 3.66, 3.62, and >3.24 log CFU/g, respectively. The results suggest that the combined treatment of TS+SAcEW has the potential as a decontamination process in fresh-cut industry.

Super-oxidized water is one of the broad spectrum disinfectants, which was introduced recently. There are many researches to find reliable chemicals which are effective, inexpensive, easy to obtain and use, and effective for disinfection of microorganisms leading hospital infections. Antimicrobial activity of super-oxidized water is promising. The aim of this study was to investigate the in-vitro antimicrobial activity of different concentrations of Medilox super-oxidized water that is approved by the Food and Drug Administration (FDA) as high level disinfectant. Material and methods In this study, super-oxidized water obtained from Medilox Soosan E & C, Korea device, which had been already installed in our hospital, was used. Antimicrobial activities of different concentrations of super-oxidized water (1/1, 1/2, 1/5, 1/10, 1/20, 1/50, 1/100) at different exposure times (1, 2, 5, 10, 30 min) against six ATCC strains, eight antibiotic resistant bacteria, yeasts and molds were evaluated using qualitative suspension test. Dey-Engley Neutralizing Broth Sigma-Aldrich, USA was used as neutralizing agent. Results Medilox was found to be effective against all standard strains (Acinetobacter baumannii 19606, Escherichia coli 25922, Enterococcus faecalis 29212, Klebsiella pneumoniae 254988, Pseudomonas aeruginosa 27853, Staphylococcus aureus 29213), all clinical isolates (Acinetobacter baumannii, Escherichia coli, vancomycin-resistant Enterococcus faecium, Klebsiella pneumoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, Bacillus subtilis, Myroides spp.), and all yeastsat 1/1 dilution in 1 minute. It was found to be effective on Aspergillus flavus at 1/1 dilution in 2 minutes and on certain molds in 5 minutes. Conclusion Medilox super-oxidized water is a broad spectrum, on-site producible disinfectant, which is effective on bacteria and fungi and can be used for the control of nosocomial infection.

This study investigated the efficacy of sanitized ice for the reduction of bacteria in the water collected from the ice that melted during storage of whole and filleted Tilapia fish. Also, bacterial reductions on the fish fillets were investigated. The sanitized ice was prepared by freezing solutions of PROSAN (an organic acid formulation) and neutral electrolyzed water (NEW). For the whole fish study, the survival of the natural microflora was determined from the water of the melted ice prepared with PROSAN and tap water. These water samples were collected during an 8 h storage period. For the fish fillet study, samples were inoculated with Escherichia coli K12, Listeria innocua, and Pseudomonas putida then stored on crushed sanitized ice. The efficacies of these were tested by enumerating each bacterial species on the fish fillet and in the water samples at 12 and 24 h intervals for 72 h, respectively. Results showed that each bacterial population was reduced during the test. However, a bacterial reduction of < 1 log CFU was obtained for the fillet samples. A maximum of approximately 2 log CFU and > 3 log CFU reductions were obtained in the waters sampled after the storage of whole fish and the fillets, respectively. These reductions were significantly (P < 0.05) higher in the water from sanitized ice when compared with the water from the unsanitized melted ice. These results showed that the organic acid formulation and NEW considerably reduced the bacterial numbers in the melted ice and thus reduced the potential for crosscontamination.

Background : Disinfection is essential for the prevention of hospital infection. Medilox, an super oxidized water generated by Medilox (SOO SAN EC CO., LTD. Yongin, Korea) was developed as a disinfectant in Korea. This is not costly and does not caany clinical problems and environmental pollution. We evaluated bactericidal activity ofMedilox against several clinical isolates and standard strains. Method : Clinical isolates and reference ATCC strains were exposed to Medilox, an super oxidized water (80 ppm ofHOCl) generated by Medilox (SOO SAN ECCO., LTD. Yongin, Korea) for the various periods (0.5, 1, 2, 5, and 10 minutes). After the exposure mixture of microorganisms and Medilox solution was inoculated into tryptic soy broth and onto tryptic soy agar, Sabouraud dextrose agar or Ogawa medium and cultured at 35C. Results: All strains of bacteria, yeasts, mycobacteria and vegetative form of Bacillus subtilis were killed within 30 seconds after an exposure to Medilox (80 ppm ofHOCl) under clean and dirty conditions. But, spore form of Bacillus subtilis was killed within 5 minutes. Conclusion: It may be recommended that Medilox can be used for the effective disinfectant for hospital environments and high-level disinfectant for hospital infection control.

The effect of acidic, electrolyzed oxidizing (EO) water and chlorinated water on the spoilage microflora of processed broiler carcasses was examined. Carcasses were sprayed for 5 s at 80 psi with tap, chlorinated, or EO water in an inside-outside bird washer. Treated carcasses were then stored at 4 C for 0, 3, 7, or 14 d, and the microbial flora of the carcasses was sampled using the whole-carcass rinse procedure. Populations of psychrotrophic bacteria and yeasts in the carcass rinsates were enumerated. Results indicated that immediately after spraying the carcasses, significantly fewer psychrotrophic bacteria were recovered from carcasses sprayed with chlorinated or EO water than from carcasses sprayed with tap water. Furthermore, significantly fewer yeasts were recovered from carcasses sprayed with EO water than from carcasses sprayed with tap or chlorinated water. The population of psychrotrophic bacteria and yeasts increased on all carcasses during refrigerated storage. However, after 14 d of storage, significantly fewer psychrotrophic bacteria and yeasts were recovered from carcasses sprayed with EO water than from carcasses sprayed with tap or chlorinated water, and significantly fewer microorganisms were recovered from carcasses sprayed with chlorinated water than from carcasses sprayed with tap water. Pseudomonas spp. and Candida spp. were the primary microbial isolates recovered from the broiler carcasses. Findings from the present study indicate that EO water can effectively be used in inside-outside bird washers to decrease the population of spoilage bacteria and yeasts on processed broiler carcasses.

This study evaluated the efficacy of neutral electrolyzed water (NEW; 64.1 mg/liter of active chlorine) to reduce populations of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Listeria monocytogenes on plastic and wooden kitchen cutting boards. Its effectiveness was compared with that of a sodium hypochlorite solution (NaClO; 62.3 mg/liter of active chlorine). Inoculated portions of cutting boards were rinsed in either NEW or NaClO solutions, or deionized water (control). Plastic boards were rinsed for 1 min and wooden boards for 1 and 5 min. After each treatment, the surviving population of each strain was determined on the surface and in the soaking water. No significant difference (P 0.05) was found between the final populations of each strain with regard to the treatment solutions (NEW or NaClO). However, a significant difference (P 0.05) was revealed between surface materials after 1 min of washing. Whereas in plastic boards the initial bacterial populations were reduced by 5 log CFU/50 cm2, in wooden cutting boards they underwent a reduction of <3 log CFU/50 cm2. A 5-min exposure time yielded reductions of about 4 log CFU/50 cm2. The surviving populations of all bacteria in NEW and NaClO washing solutions were <1 log CFU/ml after soaking both surfaces. This study revealed that NEW treatment is an effective method for reducing microbial contamination on plastic and wooden cutting boards. NEW efficacy was comparable to that of NaClO, with the advantage of having a larger storage time.

The efficacy of Electrolysed Oxidising Water (EOW) for inactivating spoilage microorganisms in process water and on minimally processed vegetables was investigated. The direct effect of EOW on three important spoilage bacteria namely; Pseudomonas fluorescens, Pantoea agglomerans or Rahnella aquatilis was determined by inoculating tap water or artificial process water with approximately 8 log CFU/ml pure culture and electrolysing the resultant solutions. The three bacteria were each reduced to undetectable levels at low (0.5 A) and relatively higher levels (1.0 A) of current in tap water and artificial process water , respectively. The residual effect of EOW on P. fluorescens, P. agglomerans or R. aquatilis was determined by incubating at room temperature 1 ml (approximately 9 log CFU/ml) pure culture suspensions in 9 ml of EOW-T (EOW produced from tap water), EOW-A (EOW produced from artificial process water supplemented with approximately 60.7 mg Cl /l and 39.3 mg Na+/l) or deionised water (control) for 0, 15, 45 or 90 min. The bactericidal activity of both EOW-T and EOW-A increased with the concentration of free oxidants and incubation period and the three bacteria were completely reduced at free oxidants-incubation period combinations of 3.88 mg/l 45 min and 5.1 mg/l 90 min in EOW-T and EOW-A, respectively. Two types of industrial vegetable process water; salad-mix and soup process water, which had each a total psychrotrophic count of approximately 8 log CFU/ml were then electrolysed. Without any NaCl addition, only 1.2 and 2.1 log reductions of the psychrotrophs in soup and salad-mix process water was attained respectively. Supplementation of the process water with approximately 60.7 mg Cl /l and 39.3 mg Na+/l afterwards resulted in complete reduction of the psychrotrophic count in both process waters, but soup process water required relatively higher levels of current compared to salad-mix water. Finally, fresh-cut lettuce was washed in EOW-T containing 3.62 mg free oxidants/l, EOW-IP (EOW produced from industrial process water) containing 2.8 mg free oxidants/l or tap water (control) for 1 or 5 min. Washing the vegetables for 1 min in EOW-T resulted in 1.9, 1.2, and 1.3 log reductions of psychrotrophs, lactic acid bacteria and Enterobacteriacae, respectively, which increased to 3.3, 2.6, and 1.9 log reductions after washing for 5 min instead. EOW-IP tested in this work had no bactericidal effect on the microflora of fresh-cut lettuce. Electrolysis could therefore be used to decontaminate process water for vegetable pre-washing and to sanitise tap water for final rinsing of vegetables, respectively.

Aim: To ascertain the efficacy of neutral electrolysed water (NEW) in reducing Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes on glass and stainless steel surfaces. Its effectiveness for that purpose is compared with that of a sodium hypochlorite (NaClO) solution with similar pH, oxidation-reduction potential (ORP) and active chlorine content. Methods and Results: First, the bactericidal activity of NEW was evaluated over pure cultures (8-5 log CFU ml-1) of the abovementioned strains: all of them were reduced by more than 7 log CFU ml-1 within 5 min of exposure either to NEW (63 mg l-1 active chlorine) or to NaClO solution (62 mg l-1 active chlorine). Then, stainless steel and glass surfaces were inoculated with the same strains and rinsed for 1 min in either NEW, NaClO solution or deionized water (control). In the first two cases, the populations of all the strains decreased by more than 6 log CFU 50 cm-2. No significant difference (P 0 05) was found between the final populations of each strain with regard to the treatment solutions (NEW or NaClO solution) or to the type of surface. Conclusions: NEW was revealed to be as effective as NaClO at significantly reducing the presence of pathogenic and spoilage bacteria (in this study, E. coli, L. monocytogenes, P. aeruginosa and S. aureus) on stainless steel and glass surfaces. Significance and Impact of the Study: NEW has the advantage of being safer than NaClO and easier to handle. Hence, it represents an advantageous alternative for the disinfection of surfaces in the food industry.