scholarly journals Exploring the potential synergistic effects of chemical disinfectants and UV on the inactivation of free-living bacteria and treatment of biofilms in a pilot-scale system

2011 ◽  
Vol 64 (6) ◽  
pp. 1247-1253 ◽  
Author(s):  
E. Vankerckhoven ◽  
B. Verbessem ◽  
S. Crauwels ◽  
P. Declerck ◽  
K. Muylaert ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Peracetic Acid ◽  
Synergistic Effects ◽  
Pilot Scale ◽  
Bacterial Suspension ◽  
Additive Effects ◽  
Free Living ◽  
Living Bacteria

The main objective of this study is to explore possible synergistic or additive effects of combinations of chemical disinfectants (sodium hypochlorite, peracetic acid, hydrogen peroxide, chlorine dioxide) and UV in their efficacy in inactivating free-living bacteria and removing biofilms. In contrast to most studies, this study examines disinfection of municipal water in a pilot-scale system using a mixed bacterial suspension, which enables a better simulation of the conditions encountered in actual industrial environments. It was shown that the combination of either hypochlorite, hydrogen peroxide, peracetic acid, or chlorine dioxide with UV yielded additive effects on the inactivation of free-living bacteria. Actual synergy was observed for the combination of UV and 5 ppm hydrogen peroxide. Regarding biofilm treatment, additive effects were observed using the combination of hydrogen peroxide and UV. The promising results obtained in this study indicate that the combination of UV and chemical disinfectants can considerably reduce the amount of chemicals required for the effective disinfection and treatment of biofilms.

Evaluation of a Sporicidal Peracetic Acid/Hydrogen Peroxide–Based Daily Disinfectant Cleaner

2014 ◽  
Vol 35 (11) ◽  
pp. 1414-1416 ◽  
Author(s):  
Abhishek Deshpande ◽  
Thriveen S. C. Mana ◽  
Jennifer L. Cadnum ◽  
Annette C. Jencson ◽  
Brett Sitzlar ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Staphylococcus Aureus ◽  
Clostridium Difficile ◽  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Infect Control Hosp ◽  
Organic Load ◽  
Methicillin Resistant

OxyCide Daily Disinfectant Cleaner, a novel peracetic acid/hydrogen peroxide–based sporicidal disinfectant, was as effective as sodium hypochlorite for in vitro killing of Clostridium difficile spores, methicillin-resistant Staphylococcus aureus, and vancomcyin-resistant enterococci. OxyCide was minimally affected by organic load and was effective in reducing pathogen contamination in isolation roomsInfect Control Hosp Epidemiol 2014;35(11):1414–1416

scholarly journals Resistance of Pseudomonas aeruginosa to Liquid Disinfectants on Contaminated Surfaces before Formation of Biofilms

2000 ◽  
Vol 83 (6) ◽  
pp. 1415-1422 ◽  
Author(s):  
Jose-Luis Sagripanti ◽  
Aylin Bonifacino
Keyword(s):  
Hydrogen Peroxide ◽  
Pseudomonas Aeruginosa ◽  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Biofilm Formation ◽  
Step Method ◽  
Quantitative Test ◽  
Viable Bacteria ◽  
One Step ◽  
Respective Product

Abstract A comparison was made of the effectiveness of popular disinfectants (Cavicide, Cidexplus, Clorox, Exspor, Lysol, Renalin, and Wavicide) under conditions prescribed for disinfection in the respective product labels on Pseudomonas aeruginosa either in suspension or deposited onto surfaces of metallic or polymeric plastic devices. The testing also included 7 nonformulated germicidal agents (glutaraldehyde, formaldehyde, peracetic acid, hydrogen peroxide, sodium hypochlorite, phenol, and cupric ascorbate) commonly used in disinfection and decontamination. Results showed that P. aeruginosa is on average 300-fold more resistant when present on contaminated surfaces than in suspension. This increase in resistance agrees with results reported in studies of biofilms, but unexpectedly, it precedes biofilm formation. The surface to which bacteria are attached can influence the effectiveness of disinfectants. Viable bacteria attached to devices may require dislodging through more than a one-step method for detection. The data, obtained with a sensitive and quantitative test, suggest that disinfectants are less effective on contaminated surfaces than generally acknowledged.

Interspecies Interactions in Dual-Species Biofilms Formed by Psychrotrophic Bacteria and the Tolerance of Sessile Communities to Disinfectants

2020 ◽  
Vol 83 (6) ◽  
pp. 951-958 ◽  
Author(s):  
LEI YUAN ◽  
NI WANG ◽  
FAIZAN A. SADIQ ◽  
GUOQING HE
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Laser Scanning ◽  
Structural Changes ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Interspecies Interactions ◽  
Mixed Species ◽  
Psychrotrophic Bacteria

ABSTRACT Biofilms on the surface of food processing equipment act as potential reservoirs of microbial contamination. Bacterial interactions are believed to play key roles in both biofilm formation and antimicrobial tolerance. In this study, Aeromonas hydrophila, Chryseobacterium oncorhynchi, and Pseudomonas libanensis, which were previously isolated from Chinese raw milk samples, were selected to establish two dual-species biofilm models (P. libanensis plus A. hydrophila and P. libanensis plus C. oncorhynchi) on stainless steel at 7°C. Subsequently, three disinfectants, hydrogen peroxide (100 ppm), peracetic acid (100 ppm), and sodium hypochlorite (100 ppm), were used to treat the developed sessile communities for 10 min. Structural changes after exposure to disinfectants were analyzed with confocal laser scanning microscopy. The cell numbers of both A. hydrophila and C. oncorhynchi recovered from surfaces increased when grown as dual species biofilms with P. libanensis. Dual-species biofilms were more tolerant of disinfectants than were each single-species biofilm. Peracetic acid was the most effective disinfectant for removing biofilms, followed by hydrogen peroxide and sodium hypochlorite. The results expand the knowledge of mixed-species biofilms formed by psychrotrophic bacteria and will be helpful for developing effective strategies to eliminate bacterial mixed-species biofilms. HIGHLIGHTS

Oxidative Disinfectants Activate Different Responses in Vibrio parahaemolyticus

2019 ◽  
Vol 82 (11) ◽  
pp. 1890-1895
Author(s):  
KAI-MING TSO ◽  
BIN NI ◽  
HIN-CHUNG WONG
Keyword(s):  
Hydrogen Peroxide ◽  
Mutant Strain ◽  
Chlorine Dioxide ◽  
Peracetic Acid ◽  
Vibrio Parahaemolyticus ◽  
Reverse Transcription Pcr ◽  
Rpos Mutant ◽  
Global Concern ◽  
Regulator Genes

ABSTRACT Vibrio parahaemolyticus is a prevalent seafoodborne enteropathogen that has become a global concern since the spread of its pandemic strain in 1996. This study investigates the responses of this pathogen to the oxidative disinfectants hydrogen peroxide, chlorine dioxide, and peracetic acid. Expression of the regulator genes oxyR and rpoS, determined by reverse transcription PCR, in V. parahaemolyticus wild-type, oxyR mutant, and rpoS mutant strains exhibited similar patterns in response to the tested oxidative disinfectants. The transcription of the rpoS gene was markedly enhanced in the oxyR mutant strain in the exponential phase. The expression of catalase KatE1 was tracked by using a LacZ fusion reporter in these strains. The experimental results revealed that KatE1 was a significant scavenger of hydrogen peroxide and peracetic acid in V. parahaemolyticus, and RpoS may partially compensate for the regulatory role of OxyR in the oxyR mutant strain. In contrast to its responses to hydrogen peroxide and paracetic acid, KatE1 was not the primary scavenger of chlorine dioxide in these V. parahaemolyticus strains. This study shows that these disinfectants activated a basic oxidative response in this pathogen with different features.

Removal of Organic Micropollutants from Contaminated Groundwater by Oxidation and Stripping

1987 ◽  
Vol 22 (1) ◽  
pp. 187-196 ◽  
Author(s):  
L. Simovic ◽  
J.P. Jones
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Chemical Oxidation ◽  
Appropriate Technology ◽  
Contaminated Groundwater ◽  
Organic Micropollutants ◽  
Air Stripping ◽  
Groundwater Samples ◽  
Iron Sulphate

Abstract In 1984, Environment Canada carried out a bench scale study on the removal of organic micropollutants from contaminated groundwater. The groundwater samples were obtained from the Special Waste Compound at Gloucester Landfill Site, near Ottawa, Ontario. The objective of the study was to evaluate the effectiveness of chemical oxidation to destroy the organic micropollutants present in this groundwater. Comparison was made between the results of ozonation and the air stripping effects. The oxidants evaluated were ozone (O3), sodium hypochlorite (NaOCl), chlorine dioxide (ClO2) and hydrogen peroxide (H2O2) with hydrated iron sulphate FeSO4 7H2O (Fenton’s reagent). The organics present in the contaminated groundwater included the following, predominantly volatile, compounds: bromodichloro-methane, bromoform, 1,1,1-trichloroethane, chloroform, 1,1-dichloroethane, dichloromethane, 1,2-dichloroethane, 1,1-dichloroethylene, and trichloroethylene. The process variables investigated were pH and oxidant dosage. The significance of low and high values of these variables was examined by using a full 22 factorial design. From the results, it appeared that the best removal efficiency was achieved by using ozone as an oxidant. However, during the experiments, it was observed that the ozonation process was being confounded with the air stripping process. Chlorine dioxide and hydrogen peroxide, in that order, were determined to be less effective oxidants. Sodium hypochlorite was found to be the least effective oxidant in this study. The results of this study demonstrated that air stripping was the most appropriate technology for the removal of the organic compounds from this groundwater.

scholarly journals Inhibitory Effect of Biocides on the Viable Masses and Matrices of Staphylococcus aureus and Pseudomonas aeruginosa Biofilms

2010 ◽  
Vol 76 (10) ◽  
pp. 3135-3142 ◽  
Author(s):  
K. Toté ◽  
T. Horemans ◽  
D. Vanden Berghe ◽  
L. Maes ◽  
P. Cos
Keyword(s):  
Hydrogen Peroxide ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Inhibitory Effect ◽  
European Guidelines ◽  
The Matrix ◽  
Antibiofilm Agents

ABSTRACT Bacteria and matrix are essential for the development of biofilms, and assays should therefore target both components. The current European guidelines for biocidal efficacy testing are not adequate for sessile microorganisms; hence, alternative discriminatory test protocols should be used. The activities of a broad range of biocides on Staphylococcus aureus and Pseudomonas aeruginosa biofilms were evaluated using such in vitro assays. Nearly all selected biocides showed a significant decrease in S. aureus biofilm viability, with sodium hypochlorite and peracetic acid as the most active biocides. Only hydrogen peroxide and sodium hypochlorite showed some inhibitory effect on the matrix. Treatment of P. aeruginosa biofilms was roughly comparable to that of S. aureus biofilms. Peracetic acid was the most active on viable mass within 1 min of contact. Isopropanol ensured a greater than 99.999% reduction of P. aeruginosa viability after at least 30 min of contact. Comparable to results with S. aureus, sodium hypochlorite and hydrogen peroxide markedly reduced the P. aeruginosa matrix. This study clearly demonstrated that despite their aspecific mechanisms of action, most biocides were active only against biofilm bacteria, leaving the matrix undisturbed. Only hydrogen peroxide and sodium hypochlorite were active on both the biofilm matrix and the viable mass, making them the better antibiofilm agents. In addition, this study emphasizes the need for updated and standardized guidelines for biofilm susceptibility testing of biocides.

scholarly journals Disinfection chemicals mode of action on the bacterial spore structure and their Raman spectra

2020 ◽  
Author(s):  
Dmitry Malyshev ◽  
Tobias Dahlberg ◽  
Krister Wiklund ◽  
Per Ola Andersson ◽  
Sara Henriksson ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Peracetic Acid ◽  
Structural Changes ◽  
Detection Methods ◽  
Laser Tweezers ◽  
Rapid Diagnostics ◽  
Spore Forming Bacteria

AbstractContamination of toxic spore-forming bacteria is problematic since spores can survive a plethora of disinfection chemicals. It is also problematic to rapidly detect if the disinfection chemical was active, leaving spores dead. Robust decontamination strategies, as well as reliable detection methods to identify dead from viable spores, are thus critical. Vibrational detection methods such as Raman spectroscopy has been suggested for rapid diagnostics and differentiation of live and dead spores. We investigate in this work, using laser tweezers Raman spectroscopy, the changes in Raman spectra of Bacillus thuringiensis spores treated with sporicidal agents such as chlorine dioxide, peracetic acid, and sodium hypochlorite. We also imaged treated spores using SEM and TEM to verify if any changes to the spore structure can be correlated to the Raman spectra. We found that chlorine dioxide did not change the Raman spectrum or the spore structure; peracetic acid shows a time-dependent decrease in the characteristic DNA/DPA peaks and ∼20 % of the spores were degraded and collapsed; spores treated with sodium hypochlorite show an abrupt drop in DNA and DPA peaks within 20 minutes all though the spore structure was overall intact, however, the exosporium layer was reduced. Structural changes appeared over several minutes, compared to the inactivation time of the spores, which is less than a minute. We conclude that vibrational spectroscopy provides powerful means to detect changes in spores but it might be problematic to identify if spores are live or dead after a decontamination procedure.

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