Microbe(s): Staphylococcus aureus, Pseudomonas aeruginosa
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.
Microbe(s): Acinetobacter baumannii, Staphylococcus aureus, Pseudomonas aeruginosa
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.
Microbe(s): Staphylococcus aureus, Pseudomonas aeruginosa
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)
Microbe(s): Staphylococcus aureus, coagulase-negative staphylococci (CNS), Pseudomonas aeruginosa
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.
Microbe(s): Staphylococcus aureus, Pseudomonas aeruginosa
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.
Microbe(s): Staphylococcus aureus
Slightly acidic electrolyzed water (SAEW), considered as a broad-spectrum and high-performance bactericide are increasingly applied in the food industry. However, its disinfection mechanism has not been completely elucidated. This study aims to examine the disinfection efficacy and mechanism of SAEW on Staphylococcus aureus, compared with that of sodium hypochlorite (NaClO) and hydrochloric acid (HCl). SAEW treatment significantly reduced S. aureus by 5.8 log CFU/mL in 1 min, while 3.26 and 2.73 log reductions were obtained with NaClO and HCl treatments, respectively. A series of biological changes including intracellular potassium leakage, TTC-dehydrogenase relative activity and bacterial ultrastructure destruction were studied following disinfection treatment of S. aureus. The results showed that SAEW decreased the relative activity of TTC-dehydrogenase by 65.84%. Comparing intracellular potassium leakage, the SAEW treatment caused a greater percent of protein leakage (108.34%) than the NaClO (18.75%) or HCl (0.84%) treatments. These results demonstrated the potent impact SAEW had on the permeability of cell membranes. In addition, the ranking of partly agglutinated cellular inclusion formation was HCl > SAEW > NaClO. It appeared that HCl, along with its low pH value, are responsible for most of the cytoplasmic disruptions. Overall, this study demonstrated that the disinfection mechanism of SAEW was disrupting the permeability of cell membrane and the cytoplasmic ultrastructures in S. aureus cells.
Microbe(s): Salmonella typhimurium, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli
Salmonella spp. may be found in the nest box of breeder chickens, cold egg-storage rooms at the farm, on the hatchery truck, or in the hatchery environment (5). These bacteria may then be spread to fertilized hatching eggs on the shell or, in some cases, may penetrate the shell and reside just beneath the surface of the eggshell.Research has demonstrated that contamination of raw poultry products with Salmonella spp. may be attributable to cross-contamination in the hatchery from Salmonella infected eggs or surfaces to uninfected baby chicks during the hatching process. Cox et al. (6 and 7) reported that broiler and breeder hatcheries were highly contaminated with Salmonella spp. Within the broiler hatchery, 71 percent of eggshell fragments, 80 percent of chick conveyor belts swabs, and 74 percent of pad samples placed under newly hatched chicks contained Salmonella spp. (6).Cason et al. (4) reported that, although fertile hatching eggs were contaminated with high levels of Salmonella typhimurium, they were still able to hatch. The authors stated that paratyphoid salmonellae do not caadverse health affects to the developing and hatching chick. During the hatching process, Salmonella spp. is readily spread throughout the hatching cabinet due to rapid air movement by circulation fans. When eggs were inoculated with a marker strain of Salmonella during hatching, greater than 80 percent of the chicks in the trays above and below the inoculated eggs were contaminated (4). In an earlier study, Cason et al. (3) demonstrated that salmonellae on the exterior of eggs or in eggshell membranes could be transmitted to baby chicks during pipping.Salmonella may persist in hatchery environments for long periods of time. When chick fluff contaminated with Salmonella was held for 4 years at room temperature, up to 1,000,000 Salmonella cells per gram could be recovered from these samples (12).Researchers have demonstrated a link between cross-contamination in the hatchery and contaminated carcasses during processing. Goren et al. (8) isolated salmonellae from three different commercial hatcheries in Europe and reported that the same serotypes found in the hatcheries could be found on processed broiler chicken carcass skin. Proper disinfection of the hatchery environment and fertile hatching eggs, therefore, is essential for reducing Salmonella on ready-to-cook carcasses.
Microbe(s): Staphylococcus aureus
The objective of this study was to investigate the combined effect of temperature (1535C), pH (3-9), and dipping time (15 min) on the inactivation of Staphylococcus aureus in broth treated with low concentration electrolyzed water (LcEW). Reductions of 1.447.12 log CFU/mL were observed in different combinations of the 3 factors. Also, a quadratic equation for S. aureus inactivation kinetic was developed by multiple regression analysis using response surface methodology. The predicted values were shown to be significantly in good agreement with experimental values as a result of the level of significance was p<0.0001. Besides, the developed model was validated by fitting with literature data and the results showed that the predictions had a good agreement with the observed data with a satisfied determination of coefficient (R2=0.963).
Microbe(s): Escherichia coli O157:H7, Staphylococcus aureus
The use of different available chlorine concentrations (ACCs) of slightly acidic electrolyzed water (SAEW; 0.5 to 30 mg/liter), different treatment times, and different temperatures for inactivating Escherichia coli O157:H7 and Staphylococcus aureus was evaluated. The morphology of both pathogens also was analyzed with transmission electron microscopy. A 3-min treatment with SAEW (pH 6.0 to 6.5) at ACCs of 2 mg/liter for E. coli O157:H7 and 8 mg/liter for S. aureus resulted in 100% inactivation of two cultures (7.92- to 8.75-log reduction) at 25 C. The bactericidal activity of SAEW was independent of the treatment time and temperature at a higher ACC (P > 0.05). E. coli O157:H7 was much more sensitive than S. aureus to SAEW. The morphological damage to E. coli O157:H7 cells by SAEW was significantly greater than that to S. aureus cells. At an ACC as high as 30 mg/liter, E. coli O157:H7 cells were damaged, but S. aureus cells retained their structure and no cell wall damage or shrinkage was observed. SAEW with a near neutral pH may be a promising disinfectant for inactivation of foodborne pathogens.
Microbe(s): Escherichia coli, Staphylococcus aureus
Suspension quantitative germicidal test showed that electrolyzed oxidizing water (EO water) was an efficient and rapid disinfectant. Disinfection rates towards E. coli (available chlorine concentration ACC: 12.40 mg/L) and Staphylococcus aureus (ACC: 37.30 mg/L) could reach 100% at 1 and 3 min, respectively. Disinfection mechanism of EO water was investigated at a molecular biological level by detecting a series of biochemical indices. The results showed that the dehydrogenase activities of E. coli and S. aureus decreased rapidly, respectively, at the rates of 45.9% and 32% in the 1st minute treatment with EO water. EO water also improved the bacterial membrane permeability, causing the rise of conductivities and the rapid leakages of intracellular DNA, K+, and proteins in 1 min. The leakages of DNA and K+ tended to slow down after about 1 min while those of proteins began to decrease a little after reaching the peak values. The sodium dodecyl sulfonate polyacrylamide gel electrophoresis (SDS-PAGE) showed that EO water destroyed intracellular proteins. The protein bands got fainter and even disappeared as the treatment proceeded. EO water s effects on the bacterial ultrastructures were also verified by the transmission electronic microscopy (TEM) photos. The disinfection mechanism of EO water was composed of several comprehensive factors including the destruction of bacterial protective barriers, the increase of membrane permeability, the leakage of cellular inclusions, and the activity decrease of some key enzymes.
Microbe(s): Staphylococcus, Staphylococcal enterotoxin-A
Electrolyzed anodic NaCl solutions [EW(+)], prepared by the electrolysis of 0.1% NaCl, have been shown to instantly inactivate most pathogens that cause food-borne disease. Elimination of food-borne pathogens does not necessarily guarantee food safety because enterotoxins produced by pathogens may remain active. We have tested whether EW(+) can inactivate Staphylococcal enterotoxin A (SEA), one of the major enterotoxins responsible for food poisoning. Fixed quantities of SEA were mixed with increasing molar ratios of EW(+), and SEA was evaluated by reversed-phase passive latex agglutination (RPLA) test, immunoassay, native polyacrylamide gel electrophoresis (PAGE), and amino acid analysis after 30 min incubations. Exposure of 70 ng, or 2.6 pmol, of SEA in 25 L of PBS to a 10-fold volume of EW(+), or ca. 64.6 103-fold molar excess of HOCl in EW(+), caused a loss of immuno-reactivity between SEA and a specific anti-SEA antibody. Native PAGE indicated that EW(+) caused fragmentation of SEA, and amino acid analysis indicated a loss in amino acid content, in particular Met, Tyr, Ile, Asn, and Asp. Staphylococcal enterotoxin-A excreted into culture broth was also inactivated by exposure to an excess molar ratio of EW(+). Thus, EW(+) may be a useful management tool to ensure food hygiene by food processing industries.