Commercial Disinfectants Research Articles

Evaluation of plasma activated liquids for the elimination of mixed species biofilms within endoscopic working channels.

The use of reusable flexible endoscopes has increased dramatically over the past decade, however despite improvements in endoscope reprocessing, the continued emergence of endoscopy-associated outbreaks as a result of multi-drug resistant bacteria has highlighted the need for a new approach to disinfection. Here,the use of plasma activated liquids (PALs) for the elimination of mixed species biofilm contamination within the working channels of endoscopes was evaluated. Cold atmospheric pressure plasma was used to chemically activate water and a commercially available pH buffered peracetic acid to create PALs. Polytetrafluoroethylene endoscope surrogate test pieces were contaminated with clinically relevant mixed species biofilms. The efficacy of PALs for the decontamination of narrow lumens was compared against the commercial disinfectant. Plasma activation was found to increase the antibiofilm capabilities of pH buffered peracetic acid by introducing reactive chemical species into the solution. Disinfection of endoscopic test pieces with plasma activated disinfectant (PAD) resulted in a 7.30 log10 reduction of biofilm contamination in 5min, surpassing the 4.39 log10 reduction observed with the currently used endoscope disinfection method. PAD also resulted in reduced regrowth and recolonization of the surface of the endoscopic test pieces. Minimal changes to the surface morphology and composition were observed following exposure to PAD in comparison to the commercial disinfectant, suggesting the developed approach is no more aggressive than current disinfection approaches.

Salmonella Infantis Adhesion to Various Surfaces and In Vitro Antimicrobial Efficacy of Commercial Disinfectants.

Salmonella Infantis poses a significant challenge in poultry production due to its persistence and resistance to disinfectants. This study investigated the survival of the S. Infantis strain on different surfaces and evaluated the efficacy of disinfectants in both preventing and treating biofilms. The survival of the tested S. Infantis strain was assessed on plastic and stainless steel surfaces after 24 and 48 h. The minimum inhibitory concentrations (MICs) of five disinfectants were determined, and their antiadhesion effectiveness was evaluated using crystal violet. The efficacy of biofilm treatment was evaluated by cell culturability. The results showed that the adhesion of S. Infantis was significantly higher on the plastic surface. The disinfectants were effective at reducing biofilm formation only within the first 24 h. Fresh solutions of disinfectants based on quaternary ammonium compounds exhibited the highest antimicrobial efficacy, while chlorocresol was the most effective for both the prevention and treatment of biofilms. The study results suggest that the presence of plastic surfaces may contribute to the dissemination of Salmonella. Additionally, the effectiveness of disinfectants varied based on storage conditions and contact time, while biofilms demonstrated reduced susceptibility compared to planktonic cells. However, given the laboratory scale of this study, further validation on a commercial scale is necessary to confirm these findings.

Temporal concentrations of Quaternary ammonium compounds in wastewater treatment effluents during the COVID-19 pandemic, 2020-2021.

Quaternary ammonium compounds (QAC) are high production chemicals used in many commercial and household disinfection products. During the SARS-CoV-2 (COVID-19) pandemic, QACs were included on lists of COVID-19 disinfectants. Increased QAC use could lead to higher levels of QACs in wastewater treatment plant (WWTP) effluents, which could subsequently be released into the environment. To evaluate QACs in WWTP effluent, three WWTPs in the northeastern United States were monitored from May 2020 through August 2021. Target QACs included six benzylalkyldimethyl ammonium compounds (BAC), three dialkyldimethyl ammonium compounds (DADMAC), two ethylbenzylalkyldimethyl ammonium compounds (EBAC), and benzethonium. At least one QAC was detected in every sample with individual concentrations up to 1600ngL-1. BAC-C14 was detected most frequently, found in 93% of effluent samples; BAC-C12, BAC-C16, EBAC-C12 and EBAC-C14 were all detected in greater than 80% of samples. Few temporal patterns were observed in QAC concentrations with respect to weekly COVID-19 cases: at WWTP 2, DADMAC-C8:C10 and DADMAC-C10 were positively correlated, and DADMAC-C8 negatively correlated. There were several seasonal trends at WWTP 1, including significant differences of ƩDADMAC, which were higher in fall than summer; ƩBAC was higher during the fall than both spring and summer; and ƩQAC where higher during the fall than spring.

Investigation of the Use of Hops (Humulus lupulus) and Calendula (Calendula officinalis) As Disinfectants on the Hatching Efficiency of Rainbow Trout (Oncorhynchus mykiss)

This study investigates the potential application of plant-based resources with antimicrobial properties, namely hops (Humulus lupulus) and calendula (Calendula officinalis), as viable alternatives to commercial disinfectants for the prevention of fungal growth during the incubation period of rainbow trout (Oncorhynchus mykiss) eggs. Fertilized eggs were examined with daily 20-minute baths in 0.25 mg, 0.5 mg, and 1 mg concentrations throughout the incubation period (33-35 days). Control group, commercial formaldehyde, hops, and calendula groups were examined in triplicate for each concentration. As a result, the lowest hatching ratio was observed in the control group with 84.77%, while the hatching ratios in the other groups were as follows: commercial disinfectant group with 86.22%, hops group with 87.44% (0.25 mg), calendula group 88% with (0.25 mg), calendula group with 89% (0.5 mg), calendula group with 89.33% (1 mg), hops group with 89.55% (0.5 mg), and the highest hatching ratio was found in the hops group with 90.66% (1 mg). The lowest survival rate was observed in the control group with 85.22%, with the survival rates of the other groups were 86.44% in the commercial disinfectant group, 87.55% (0.25 mg) in the hops group, 88.55% (0.25 mg) in the calendula group, 88.88% (0.5 mg) in the calendula group, 89.33% (1 mg) in the calendula group, 89.55% (0.5 mg) in the hops group, and the highest survival rate was 90.11% (1 mg) in the hops group. In conclusion, it was specified that plant-based by-products (hops and calendula) could be used as alternative disinfectants to commercial chemicals in the disinfection of rainbow trout eggs and fry, and the most appropriate concentration was 1 mg.

Global transcriptional response of Pseudomonas aeruginosa to UVA radiation.

Ultraviolet A (UVA) radiation is the major fraction of UV radiation reaching the Earth's surface. Its harmful effects on microorganisms, due mainly to oxidative damage, have been exploited for development of natural solar and commercial UVA-based disinfection methods. In this work, the global transcriptional response of Pseudomonas aeruginosa exposed to ultraviolet A (UVA) radiation was analyzed. To conduct this study, we analyzed the whole transcriptome of the PAO1 strain grown to logarithmic phase under sublethal doses of UVA or in the dark. We found that a total of 298 genes responded to UVA with a change of at least two-fold (5.36% of the total P. aeruginosa genome), and showed equal amount of induced and repressed genes. An important fraction of the induced genes were involved in the response to DNA damage and included induction of SOS, prophage and pyocins genes. The results presented in this study suggest that one of the main UVA targets are proteins carrying [Fe-S] clusters since several genes involved in the processes of synthesis, trafficking and assembly of these structures were upregulated. The management of intracellular iron levels also seems to be a robust response to this stress factor. The strong induction of genes involved in denitrification suggest that this pathway and/or reactive nitrogen species such as nitric oxide could have a role in the response to this radiation. Regarding the down-regulated genes, we found many involved in the biosynthesis of PQS, a quorum-sensing signal molecule with a possible role as endogenous photosensitizer.

Efficacy of Commercial Disinfectants Against Black Root Rot (Berkeleyomyces rouxiae) and Verticillium Wilt (Verticillium dahliae) Pathogens of Cotton

Black root rot (BRR) and Verticillium wilt of cotton are caused by soilborne Berkeleyomyces rouxiae and Verticillium dahliae, respectively, and can individually cause yield loss of a 10–50% in New South Wales (NSW). Both diseases were first detected in a northern valley of NSW but are now present across the state. ‘Come Clean Go Clean’ is a widely practiced biosecurity measure used to minimize the risk of further introducing the pathogens from one field to another by restricting the movement of soil-contaminated farm equipment and machinery. We rely on cleaning agents to effectively wash down and decontaminate the equipment and machinery. In this study, we examined 12 locally available, commercial disinfectants for their efficacy against B. rouxiae and V. dahliae reproductive structures with and without soil contamination of 10% (w/v). We found a significant interaction between pathogens, disinfectants, and soil amendment (p < 0.01). The germination of B. rouxiae chlamydospores and endoconidia in both the presence and absence of soil contamination was completely suppressed even after a short 10 sec exposure to 70% ethanol and 25% bleach. Both 70% ethanol and bleach were highly lethal at 10 sec exposures in similar assays against V. dahliae microsclerotia and conidia. Some other commercial products were able to reduce the germination rate significantly but did not completely kill microsclerotia and conidia even after 30 min of exposure. The lethal effect against B. rouxiae and V. dahliae warrants further exploration of both 70% ethanol and bleach to improve their field applications. Additionally, the efficacy of most tested commercial disinfectants was time-dependent; however, this is not recommended on the labels for their effectiveness. This study provides an additional integrated disease management option aiming to limit the spread of the pathogens.

Highly Effective Biocides against Pseudomonas aeruginosa Reveal New Mechanistic Insights Across Gram-Negative Bacteria.

Pseudomonas aeruginosa is a major nosocomial pathogen that persists in healthcare settings despite rigorous disinfection protocols due to intrinsic mechanisms conferring resistance. We sought to systematically assess cationic biocide efficacy against this pathogen using a panel of multidrug-resistant P. aeruginosa clinical isolates. Our studies revealed widespread resistance to commercial cationic disinfectants that are the current standard of care, raising concerns about their efficacy. To address this shortcoming, we highlight a new class of quaternary phosphonium compounds that are highly effective against all members of the panel. To understand the difference in efficacy, mechanism of action studies were carried out, which identified a discrete inner-membrane selective target. Resistance selection studies implicated the SmvRA efflux system (a transcriptionally regulated, inner membrane-associated efflux system) as a major determinant of resistance. This system is also implicated in resistance to two commercial bolaamphiphile antiseptics, octenidine and chlorhexidine, which was further validated herein. In sum, this work highlights, for the first time, a discrete inner-membrane specific mechanism for the bolaamphiphile class of disinfectants that contrasts with the prevailing model of indiscriminate membrane interactions of commercial amphiphiles paving the way for future innovations in disinfectant research.

Assessment of biocidal efficacy of zinc oxide-zeolite nanocomposites as a novel water disinfectant against commercial disinfectants used in water purification

Water microbial contamination is a serious issue that poses a risk to both animal and human health. One hundred and twenty water were samples collected from main water source and drinkers from a poultry farm. Different bacterial pathogens were isolated from water sources. Escherichia (E.) coli, Pseudomonas (P.) aureoginosa, (Salmonella) Salmonella (s). Typhimurim, Aeromonas (A.) hydrophila at different percentages. Variable degree of bacterial resistance to some commercial disinfectants commonly used to disinfect water system (iodine, terminator and H2O2). Nanoparticles were used to control bacteria in water. About the safety investigation for the prepared nanomaterials, the work results demonstrated that zinc oxide (ZnO) nanoparticles (NPs) exhibit the highest safety profile among the manufactured materials. The median fatal dose (LD50) for ZnO NPs was determined to be 3709 mg/kg body weight. In comparison, the LD50 values for zeolites and nanocomposites were 3251 mg/kg and 2658 mg/kg, respectively. Therapeutic dosages were estimated based on the LD50. Zeolite NPs, ZnO NPs and ZnO/zeolite NPs showing promising results in control of those bacteria. It was concluded that the escalating resistance of bacteria to disinfectants have led to a need to find alternative such as nanoparticles that proved promising results in control of pathogens, particularly it showed a safe effect on laboratory animals.

Assessment of Lactococcus Cremoris preparations for the pre- and post-milking teat disinfection

Good hygienic milking practices including the disinfection of the cow teat skin before and after milking aimed at preventing the occurrence of new intramammary infections (IMI) in dairy cows. This practice is generally performed using disinfectants, and in the current context of attention to the emergence of resistances, it is of greatest interest to evaluate alternative solutions that can expand treatment options. We assessed the efficacy of a pre-dipping and a post-dipping product based on the bacteriocin-containing culture of Lactococcus cremoris strain FT27, as compared to commercial disinfectants. FT27 was selected for the bactericidal activity in vitro against food pathogens. In the present study, it also revealed a high bactericidal activity against the main mastitis pathogens, most likely related to Nisin A production, according to genomic and proteomic analysis. The lactococcus-based preparations were applied in two commercial dairy farms in Northern Italy. Overall, 298 dairy cows were enrolled, 141 in the treated group (TR), and 157 in the control group (CTR). The cows were sampled at quarter level every two weeks for 3 months. During the trial, all cows showed a good health status. The hygiene level for udder, flanks and legs was generally good (on average < 3 score); the udder hygiene was significantly worse (P < 0.01) in the CTR group. The teat apex hyperkeratosis was overall low (on average < 2 score). We recorded no significant differences between the two experimental groups in the Somatic Cell Count (SCC) values and the bacteriological results. The overall frequency of new IMI was low, ranging 0.6 − 0.5% for S. aureus in the TR or CTR group respectively, to 2.6–4.4% for NASM. Regarding Str. spp., the new IMI accounted for 1.7% or 1.9% in the TR or CTR group, respectively. Notably, the incidence of S. aureus new IMI did not increase during the study, even though neither of the two herds segregated the positive cows. The non-inferiority test showed that the Lactococcus-based pre- and post-dipping products had an efficacy comparable to proven commercial disinfectants in maintaining udder health and preventing new IMI, thus representing a possible alternative to current teat dip products.

Toxicity of Common Acaricides, Disinfectants, and Natural Compounds against Eggs of Rhipicephalus annulatus.

Ticks pose a significant threat due to their ability to lay thousands of eggs, which can persist in the environment for extended periods. While the impact of various compounds on adult and larval ticks has been studied, research on their efficacy against tick eggs is limited. This study evaluated the ovicidal activity of commercial acaricides, disinfectants, and natural products against Rhipicephalus annulatus eggs using the egg hatch assay (EHA). Deltamethrin and cypermethrin caused a non-significant inhibition of hatching (IH%), even at concentrations higher than the recommended levels. By contrast, the acaricides chlorpyrifos, phoxim, and amitraz significantly inhibited hatching at all tested concentrations. Ivermectin also demonstrated significant IH% at various concentrations but did not fully inhibit the hatching process. Among the disinfectants tested, Virkon-S®, TH4, and Chlorox showed insignificant effects, whereas formalin achieved an IH% of only 34.1% at a high concentration of 200 mg/mL. Natural products, carvacrol and thymol, exhibited significant ovicidal activity, with a significant IH%. In a semi-field application, phoxim (0.5 mg/mL) and deltamethrin (0.05 mg/mL) were sprayed on tick eggs on pasture soil from a farm. The results indicated that phoxim-treated eggs had a 40% IH%, while deltamethrin-treated eggs showed only an 8.79% IH%. In conclusion, the acaricides amitraz, phoxim, and chlorpyrifos, as well as the natural products carvacrol and thymol, caused significant toxicity to R. annulatus eggs.

Reuterin Enhances the Efficacy of Peracetic Acid Against Multi-species Dairy Biofilm.

Biofilms may contain pathogenic and spoilage bacteria and can become a recurring problem in the dairy sector, with a negative impact on product quality and consumer health. Peracetic acid (PAA) is one of the disinfectants most frequently used to control biofilm formation and persistence. Though effective, it cannot be used at high concentrations due to its corrosive effect on certain materials and because of toxicity concerns. The aim of this study was to test the possibility of PAA remaining bactericidal at lower concentrations by using it in conjunction with reuterin (3-hydroxypropionaldehyde). We evaluated the efficacy of PAA in pure form or as BioDestroy®, a PAA-based commercial disinfectant, on three-species biofilms formed by dairy-derived bacteria, namely Pseudomonas azotoformans PFlA1, Serratia liquefaciens Sl-LJJ01, and Bacillus licheniformis Bl-LJJ01. Minimum inhibitory concentrations of the three agents were determined for each bacterial species and the fractional inhibitory concentrations were then calculated using the checkerboard assay. The minimal biofilm eradication concentration (MBEC) of each antibacterial combination was then calculated against mixed-species biofilm. PAA, BioDestroy®, and reuterin showed antibiofilm activity against all bacteria within the mixed biofilm at respectively 760ppm, 450ppm, and 95.6mM. The MBEC was lowered significantly to 456ppm, 337.5ppm, and 71.7mM, when exposed to reuterin for 16h followed by contact with disinfectant. Combining reuterin with chemical disinfection shows promise in controlling biofilm on food contact surfaces, especially for harsh or extended treatments. Furthermore, systems with reuterin encapsulation and nanotechnologies could be developed for sustainable antimicrobial efficacy without manufacturing disruptions.

Advances in Nanoemulsion Formulations for Enhanced Drug Delivery: A Comprehensive Review

Abstract: Nanoemulsions (NEs) have emerged as adaptable medication delivery methods with extensive applications in both pharmaceuticals and cosmeceuticals. This comprehensive review delves into the myriad advantages of NEs, ranging from enhanced drug absorption to providing stability for chemically unstable compounds. NEs exhibit promising potential as substitutes for liposomes, offering improved performance in various formulations. In the realm of cosmeceuticals, NEs play a pivotal role in enabling rapid skin penetration while maintaining skin moisturization, thanks to their visually appealing coating. Their ability to deliver active ingredients efficiently makes them an attractive option for cosmetic formulations seeking enhanced efficacy. Moreover, this review sheds light on the involvement of NEs in antimicrobial therapies and gene therapy, underscoring their versatility and potential in addressing diverse medical challenges. Additionally, NEs find applications in commercial disinfectants, further highlighting their broad utility beyond traditional drug delivery systems. Furthermore, the review discusses innovative strategies, such as solid self-nanoemulsifying drug delivery systems (S-SNEDDS), which offer advantages in terms of stability, drug loading capacity, and patient compliance. By exploring these strategies, researchers aim to overcome existing limitations and optimize the therapeutic potential of NEs.

Construction of CDs@β-CD@CCM ratiometric fluorescence probe for FRET-based ClO–-sensing

β-Cyclodextrin (β-CD)-functionalized carbon quantum dots (CDs) loaded with curcumin (CCM) were used for ClO-sensing with high sensitivity and selectivity. This fluorescence resonance energy transfer (FRET)-based sensor was created through attaching CCM to the CDs via β-CD linker. CCM could get into the interior of β-CD triggering the FRET from CDs to CCM, providing an 'off' state of the CDs. However, the effect of FRET was weakened by the ClO-, because the o-methoxyphenol structure from CCM was oxidized to be benzoquinone. The fluorescence intensity of CDs@β-CD@CCM at 440 nm can be heightened and 520 nm from CCM can decrease along with the increased ClO-. Therefore, a ratiometric fluorescence probe for ClO-sensing is successfully constructed. It conforms to a polynomial curve equation which is I440/I520= -0.0268 + 0.0315 CClO-+ 0.0055[CClO-]2(R2= 0.9958) between 0 and 18.4μM ClO-. Furthermore, we also obtain excellent results using this spectrophotometric method for ClO--sensing in pure water and commercial disinfectants, which afford potential in the environment monitoring area. We expect this sensing platform could be helpful in other analogous probes in relevant fields.

In vitro efficiency of teat disinfectants with organic matter against Staphylococcus aureus isolated from cows with mastitis

Four strains of Staphylococcus aureus isolated from cows with mastitis were assessed as to in vitro sensitivity to four commercial disinfectants (chlorine, polvidone-iodine, chlorhexidine, and lactic acid) used in teat pre- and post-dipping, in the presence and absence of organic matter. The concentration of the disinfectants was determined in accordance with the Brazilian Pharmacopoeia. Four isolates identified as S. aureus from cows diagnosed with subclinical mastitis were subjected to susceptibility testing against disinfectants through an absorbance evaluation at 600 nm on a spectrophotometer. Exposure times (15”, 30”, 60” and 90”) were clocked, and streaking was performed in Brain Heart Infusion (BHI) medium. The iodine sample presented a lower concentration (1.9%) than that given by the manufacturer (2.5%). There was greater (p &lt; 0.05) in vitro disinfectant activity for chlorhexidine and chlorine, with and without organic matter. However, inhibition by organic matter occurred more intensely in the iodine disinfectant (99.0%). The inhibition percentage of S. aureus against iodine and lactic acid at 15, 30, 60 and 90 s was numerically lower than against chlorhexidine and chlorine, regardless of organic matter. Therefore, chlorhexidine and chlorine have greater inhibitory activity against S. aureus, both with and without organic matter.

Functional Living Materials for Virus Disinfection Based on Engineered Bacillus subtilis Biofilm by Displaying Viral Affinity Peptides and Expressing Protease

AbstractGlobal pandemics caused by pathogenic viruses have highlighted the need to develop effective and sustainable materials to defend against these viruses. However, most commercial viral disinfection materials rely on precious metals, which are toxic. In this study, an engineered living material based on Bacillus subtilis biofilms is presented that can effectively remove Influenza A virus and SARS‐CoV‐2 from water. First, B. subtilis biofilm is used to display the H1N1 and H5N1 specific binding peptide C40 and SARS‐CoV‐2 specific binding peptide SBP1; thus, the biofilm materials has outstanding efficacy against H1N1, H5N1, and SARS‐CoV‐2 pseudovirus from water. In addition to capturing the virus, these biofilm materials can also inactivate the virus by secreting alkaline protease AprE, which effectively degrades the viral proteins at temperatures of 4, 16, 25, and 37 °C. Furthermore, to constrain bacterial growth and prevent the leakage of genetically modified organisms, a suicide genetic circuit using the quorum‐sensing system ComQXPA to control Lytc expression is constructed, leading to bacterial lysis. Overall, this study demonstrates a novel, effective, and sustainably engineered living material for preventing viral transmission. This material provides a safeguard for public health and promotes environmentally friendly governance.

Investigation of the disinfection efficiency of commercial hydrogen peroxide, chlorine dioxide, and chlorine disinfectant on different surfaces.

The disinfection efficiency of disinfectants differs in specific conditions. This study aimed to investigate the disinfection efficiency of commercial hydrogen peroxide, chlorine dioxide, and chlorine disinfectant on real field surfaces and provide data for precise disinfection. Simulated field disinfection and field disinfection methods were conducted to quantitatively evaluate the disinfection efficiency of hydrogen peroxide, chlorine dioxide, and sodium dichloroisocyanurate. The log10 reduction of biological indicators, Escherichia coli (ATCC 8099) and Staphylococcus aureus (ATCC 6538), was calculated. Next, the reduction in natural bacteria on the surfaces of a food production and processing workshop and a biosafety laboratory was determined. The 3 commercial disinfectants evaluated were effective against E coli and S aureus, with a reduction of more than 3.00 log10 colony-forming units/mL tested for an exposure time of 15 minutes with 3.5% hydrogen peroxide, 100 mg/L chlorine dioxide, and 250 mg/L sodium dichloroisocyanurate. The natural load in the food production and processing workshop decreased by more than 90% using 10.5% hydrogen peroxide with an exposure time of 30 minutes. The same disinfection level in the biosafety level 2 laboratory was achieved by 500 mg/L chlorine dioxide at an exposure time of 60 minutes and 450 mg/L sodium dichloroisocyanurate at 60 minutes. This study provides a reference for precise disinfection of surfaces in the food industry and biosafety laboratories.

Efficacy of sodium hypochlorite in overcoming antimicrobial resistance and eradicating biofilms in clinical pathogens from pressure ulcers.

Sodium hypochlorite (NaOCl) is widely recognized for its broad-spectrum antimicrobial efficacy in skin wound care. This study investigates the effectiveness of NaOCl against a range of bacterial and fungal isolates from pressure ulcer (PU) patients. We analyzed 20 bacterial isolates from PU patients, comprising carbapenem-resistant Klebsiella pneumoniae (CRKP), multidrug-resistant Acinetobacter baumannii (MDRAB), methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible Staphylococcus aureus (MSSA), along with 5 Candida albicans isolates. Antibiotic resistance profiles were determined using standard susceptibility testing. Whole-genome sequencing (WGS) was employed to identify antimicrobial resistance genes (ARGs) and disinfectant resistance genes (DRGs). Genetic determinants of biofilm formation were also assessed. The antimicrobial activity of NaOCl was evaluated by determining the minimum inhibitory concentration (MIC) and the minimal biofilm eradication concentration (MBEC) for both planktonic and biofilm-associated cells. CRKP and MDRAB showed resistance to fluoroquinolones and carbapenems, while MRSA exhibited resistance to β-lactams and levofloxacin. MSSA displayed a comparatively lower resistance profile. WGS identified significant numbers of ARGs in CRKP and MDRAB, with fewer DRGs compared to MRSA and MSSA. All isolates possessed genes associated with fimbriae production and adhesion, correlating with pronounced biofilm biomass production. NaOCl demonstrated substantial antimicrobial activity against both planktonic cells and biofilms. The MIC90 for planktonic bacterial cells was 0.125 mg/mL, and the MBEC90 ranged from 0.225 to 0.5 mg/mL. For planktonic C. albicans, the MIC90 was 0.150 mg/mL, and the MBEC90 was 0.250 mg/mL. These results highlight the challenge in treating biofilm-associated infections and underscore the potential of NaOCl as a robust antimicrobial agent against difficult-to-treat biofilm infections at concentrations lower than those typically found in commercial disinfectants.

A Label-Free Optical Flow Cytometry Based-Method for Rapid Assay of Disinfectants' Bactericidal Activity.

Selecting the appropriate disinfectant to control and prevent healthcare-associated infections (HAIs) is a challenging task for environmental health experts due to the large number of available disinfectant products. This study aimed to develop a label-free flow cytometry (FCM) method for the rapid evaluation of bactericidal activity and to compare its efficacy with that of standard qualitative/quantitative suspension tests. The bactericidal efficiency of eight commercial disinfectants containing quaternary ammonium compounds (QACs) was evaluated against four strains recommended by EN 13727 (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus hirae) and four multidrug-resistant pathogens. The proposed FCM protocol measures changes in scattered light and counts following disinfectant exposure, neutralization, and culture steps. Unlike other available FCM-based methods, this approach does not rely on autofluorescence measurements, impedance cytometry, or fluorescent dyes. The FCM scattered light signals revealed both decreased count rates and morphological changes after treatment with minimum inhibitory concentrations (MICs) and higher concentrations for all tested bacteria. The results from the FCM measurements showed excellent correlation with those from standard assays, providing a rapid tool for monitoring the susceptibility profile of clinical, multidrug-resistant pathogens to chemical disinfectants, which could support infection prevention and control procedures for healthcare environments. This label-free FCM protocol offers a novel and rapid tool for environmental health experts, aiding in the optimization of disinfectant selection for the prevention and control of HAIs.

Exploring the Antimicrobial Efficacy of Low-Cost Commercial Disinfectants Utilized in the Agro-Food Industry Wash Tanks: Towards Enhanced Hygiene Practices.

The increase in vegetable consumption has underlined the importance of minimizing the risks associated with microbiological contamination of fresh produce. The critical stage of the vegetable washing process has proven to be a key point for cross-contamination and the persistence of pathogens. In this context, the agri-food industry has widely adopted the use of disinfectants to reduce the bacterial load in the wash water. Therefore, we conducted laboratory-scale experiments in order to demonstrate the antimicrobial activity of disinfectants used in the wash tank of agro-food industries. Different wash water matrices of shredded lettuce, shredded cabbage, diced onion, and baby spinach were treated with sodium hypochlorite (NaClO), chlorine dioxide (ClO2), and per-oxyacetic acid (PAA) at recommended concentrations. To simulate the presence of pathogenic bacteria, a cocktail of E. coli O157:H7 was inoculated into the process water samples (PWW) to determine whether concentrations of disinfectants inhibit the pathogen or bring it to a viable non-culturable state (VBNC). Hereby, we used quantitative qPCR combined with different photo-reactive dyes such as ethidium monoazide (EMA) and propidium monoazide (PMA). The results indicated that concentrations superior to 20 ppm NaClO inhibit the pathogen E. coli O157:H7 artificially inoculated in the process water. Concentrations between 10-20 ppm ClO2 fail to induce the pathogen to the VBNC state. At concentrations of 80 ppm PAA, levels of culturable bacteria and VBNC of E. coli O157:H7 were detected in all PWWs regardless of the matrix. Subsequently, this indicates that the recommended concentrations of ClO2 and PAA for use in the fresh produce industry wash tank do not inhibit the levels of E. coli O157:H7 present in the wash water.

A Flow-Through Biosensor System Based on Pillar[3]Arene[2]Quinone and Ferrocene for Determination of Hydrogen Peroxide and Uric Acid

Simple and reliable electrochemical sensors are highly demanded in medicine and pharmacy for the fast determination of metabolites and biomarkers of diseases. In this work, a flow-through biosensor system was developed on the base of a screen-printed carbon electrode modified with pillar[3]arene[2]quinone and ferrocene implemented in carbon black. The modification was performed in a single step and resulted in the formation of a stable layer with good operation characteristics. Uricase was immobilized on the inner walls of a replaceable reactor by carbodiimide binding. A flow-through cell was manufactured by 3D printing from poly(lactic acid). The flow-through system was first optimized on the hydrogen peroxide assay and then used for the determination of 1 nM–0.1 mM uric acid (limit of detection 0.3 nM, 20 measurements per hour). Implementation of ferrocene resulted in a synergetic increase in the cathodic current of H2O2 reduction measured by flow switching in chronoamperometric mode. The developed system was tested on the determination of uric acid in artificial urine and Ringer–Locke solution and showed a recovery rate of 96–112%. In addition, the possibility of determination of H2O2 in commercial disinfectants was shown. Easy assembly, fast and reliable signal and low consumption of the reagents make the system developed attractive for routine clinical analysis of metabolites.