Commercial Disinfectants Research Articles

Study of Combined Effect of Bacteriophage vB3530 and Chlorhexidine on the Inactivation of Pseudomonas aeruginosa

BackgroundChlorhexidine (CHG) is a disinfectant commonly used in hospitals. However, it has been reported that the excessive use of CHG can cause resistance in bacteria to this agent and even to other clinical antibiotics. Therefore, new methods are needed to alleviate the development of CHG tolerance and reduce its dosage. This study aimed to explore the synergistic effects of CHG in combination with bacteriophage against CHG-tolerant Pseudomonas aeruginosa (P. aeruginosa) and provide ideas for optimizing disinfection strategies in clinical environments as well as for the efficient use of disinfectants.MethodsThe CHG-tolerant P. aeruginosa strains were isolated from the First Affiliated Hospital of Wenzhou Medical University in China. The bacteriophage vB3530 was isolated from the sewage inlet of the hospital, and its genome was sequenced. Time-killing curve was used to determine the antibacterial effects of vB3530 and chlorohexidine gluconate (CHG). The phage sensitivity to 16 CHG-tolerant P. aeruginosa strains and PAO1 strain was detected using plaque assay. The emergence rate of resistant bacterial strains was detected to determine the development of phage-resistant and CHG-tolerant strains. Finally, the disinfection effects of the disinfectant and phage combination on the surface of the medical devices were preliminarily evaluated.ResultsThe results showed that (1) CHG combined with bacteriophage vB3530 significantly inhibited the growth of CHG-resistant P. aeruginosa and reduced the bacterial colony forming units (CFUs) after 24 h. (2) The combination of CHG and bacteriophage inhibited the emergence of phage-resistant and CHG-tolerant strains. (3) The combination of CHG and bacteriophage significantly reduced the bacterial load on the surface of medical devices.ConclusionsIn this study, the combination of bacteriophage vB3530 and CHG presented a combined inactivation effect to CHG-tolerant P. aeruginosa and reduced the emergence of strains resistant to CHG and phage. This study demonstrated the potential of bacteriophage as adjuvants to traditional disinfectants. The use of bacteriophage in combination with commercial disinfectants might be a promising method for controlling the spread of bacteria in hospitals.

Synthesis of Mesoporous Lanthanum-Doped SnO2 Spheres for Sensitive and Selective Detection of the Glutaraldehyde Disinfectant.

Glutaraldehyde disinfectant has been widely applied in aquaculture, farming, and medical treatment. Excessive concentrations of glutaraldehyde in the environment can lead to serious health hazards. Therefore, it is extremely important to develop high-performance glutaraldehyde sensors with low cost, high sensitivity, rapid response, fabulous selectivity, and low limit of detection. Herein, mesoporous lanthanum (La) doped SnO2 spheres with high specific surface area (52-59 m2 g-1), uniform mesopores (with a pore size concentrated at 5.7 nm), and highly crystalline frameworks are designed to fabricate highly sensitive gas sensors toward gaseous glutaraldehyde. The mesoporous lanthanum-doped SnO2 spheres exhibit excellent glutaraldehyde-sensing performance, including high response (13.5@10 ppm), rapid response time (28 s), and extremely low detection limit of 0.16 ppm. The excellent sensing performance is ascribed to the high specific surface area, high contents of chemisorbed oxygen species, and lanthanum doping. DFT calculations suggest that lanthanum doping in the SnO2 lattice can effectively improve the adsorption energy toward glutaraldehyde compared to pure SnO2 materials. Moreover, the fabricated gas sensors can effectively detect commercial glutaraldehyde disinfectants, indicating a potential application in aquaculture, farming, and medical treatment.

Mitigation of the negative impacts of 84 disinfectant exposure for phenol treatment by an electro-enhanced SBR: Performance, oxidative stress, iron homeostasis and antibiotic resistance genes

A huge application of 84 disinfectant, a commercial disinfection product, attracts widely concerns as the primary recipients of 84 disinfectant are wastewater treatment plants (WWTPs). However, the impacts of 84 disinfectant on WWTPs and corresponding mitigation strategies remain unclear. Herein, we systematically investigated the effects of 84 disinfectant on the phenol treatment performance and microbial oxidative stress responses in control sequencing batch reactor (SBR) and electro-enhanced SBR (E-SBR). At a low concentration, the 84 disinfectant had no impact on the phenol treatment performance in both SBR and E-SBR. At higher concentrations, the 84 disinfectant significantly inhibited the phenol treatment performance in SBR, while the electrical stimulation in E-SBR significantly alleviated these negative impacts. Electrical stimulation alleviates the detrimental impacts on key enzymes involved in phenol degradation; it activates the antioxidant system, repressing the generation of reactive oxygen species. Electrical stimulation also inhibits the DNA repair system response, reduces cell membrane permeability, enhances cell membrane integrity, and maintains iron homeostasis by activating the ferric uptake regulator (Fur), ultimately reduces the total abundance of antibiotic resistance genes (ARGs) by changing their host bacteria.

A test battery approach for ecotoxicological evaluation of disinfectants prepared on the basis of sodium hypochlorite

Abstract The research is related to the assessment of the overall sensitivity and applicability of many bioassays representing different trophic levels for the preliminary ecotoxicological testing of commercial disinfectants marked as SA (SAVO, Bochemie a.s., Czech Republic) and DoAm (Dom Amor, BOOS – Biologické substancie, Slovak Republic). Disinfectants were prepared based on sodium hypochlorite (NaOCl). SA contains only NaOCl while earthworm enzymes enrich DoAm. In both commercial products, the NaOCl content did not exceed 5%; pure NaOCl was used as a 10% solution as well. For bioassay, water organisms (Vibrio fischeri, Desmodesmus subspicatus, Daphnia magna and Tubifex tubifex) situated in various trophic levels were used. All the tests were confirmed as suitable for the determination of chlorine’s adverse effects. Because the organisms’ reactions to the tested disinfectants varied, they can be arranged in the following rank order of sensitivity: V. fischeri ≥ D. subspicatus >> D. magna >> T. tubifex. The toxicity of the tested substances (NaOCl, SA, DoAm) depends on the length of exposure, the species of the organism and FAC (free available chlorine) content. The effective concentrations of the tested products ranged from 0.13 to 8.18 μL L–1, i.e., 0.014 to 0.26 mg L–1 of FAC. However, in the tests with T. tubifex and V. fischeri the toxic effect of NaOCl was the weakest; the tests with other two organisms confirmed this compound as the most toxic. Only for T. tubifex (96 hrs) did SA have a more adverse effect than DoAm.

FTIR Spectroscopic Study Of Inhibition of Chloroxylenol-Based Disinfectant Against Salmonella enterica serovar Thyphimurium Biofilm

The present work was performed to determine the impacts of commercial disinfectants against biomass, viability, and biochemical composition of Salmonella enterica serovar Thyphimurium ATCC14028 biofilm. Salmonella Thyphimurium biofilm grown in microplates was exposed to commercial disinfectants namely sodium hypochlorite, benzalkonium chloride, chloroxylenol, and sodium dodecyl-benzene sulfonate-based disinfectants. Biofilm biomass, biofilm viability, and biochemical composition of the biofilm were determined using crystal violet assay, resazurin assay and Fourier transform infrared (FTIR) spectroscopy respectively. Results demonstrated that, among four commercial disinfectants, chloroxylenol-based disinfectant showed the highest inhibition against S. Thyphimurium biofilm. It remarkably hindered biofilm biomass and biofilm viability at all tested concentrations (0.78%-25%). Half-maximal biofilm inhibitory concentration (BIC50) of chloroxylenol-based disinfectant (5.06%) was found to be the lowest among the tested disinfectants. Meanwhile, S. Thyphimurium biofilm treated with chloroxylenol-based disinfectant exhibited changes in FTIR spectral peaks associated with lipid (1460 cm-1), protein (630 cm-1, 702 cm-1, 1550 cm-1 & 1650 cm-1), and nucleic acid (1080 cm-1 & 1229 cm-1). The findings of the present study suggest that the inhibition of chloroxylenol-based disinfectant against S. Thyphimurium biofilm is mediated by structural changes of biofilm.

Evaluation of the Efficacy of Commercial Disinfectants against African Swine Fever Virus.

African swine fever (ASF) is an economically important disease due to high morbidity and mortality rates and the ability to affect all ages and breeds of pigs. Biosecurity measures to prevent the spread of the causative agent, African swine fever virus (ASFV), include prescriptive cleaning and disinfection procedures. The aim of this study was to establish the biocidal effects of twenty-four commercially available disinfectants including oxidizing agents, acids, aldehydes, formic acids, phenol, and mixed-class chemistries against ASFV. The products were prepared according to the manufacturer's instructions and a suspension assay was performed with ASFV strain, BA71V using Vero cells (African green monkey cells) to test efficacy in reducing ASFV infection of cells. Generally, disinfectants containing formic acid and phenolic compounds, as well as oxidizing agents reduced viral titers of ASFV by over 4 log10 at temperatures ranging from 4 °C to 20 °C. Hydrogen peroxide, aldehyde, and quaternary ammonium compounds containing disinfectants were cytotoxic, limiting the detection of viral infectivity reductions to less than 4 log10. These preliminary results can be used to target research on disinfectants which contain active ingredients with known efficacy against ASFV under conditions recommended for the country where their use will be applied.

Comparative Effectiveness and Persistence of Antimicrobial Durability in Dry and Wet States of a Novel Antimicrobial Surface Disinfectant

Aims: We evaluated a novel disinfectant (VR) and seven comparators (disinfectants A–G) against resistant pathogens common in healthcare settings. Methods and Results: VR at different dilutions, along with commercial disinfectants A–G, was tested against surrogate viruses, and resistant bacterial and fungal pathogens. Surrogate viruses had an initial concentration of ~1 × 108 mL−1, and bacterial and fungal isolates had an initial concentration of ~1 × 106 mL−1 on Siliconee surfaces. After the application of VR or a comparator disinfectant, surfaces were tested for the reduction in microbial loads after 30 s and 5 min wet exposures, and after a 24 h dry residue exposure. Sterile deionized water was used as a control. The VR at a concentration of 4.68% was superior to all comparator disinfectants against most pathogens in wet and dry testing. The VR at 7.8% concentration showed the highest pathogen-reduction rate among all comparator disinfectants when tested against all pathogens. Conclusions: Overall, the novel VR disinfectant was the most effective disinfectant in both wet and dry residue states against the range of tested pathogens. Significance and Impact of the Study: VR is a broadly effective disinfectant combination for use in high-risk settings, particularly those in which intervals between applications of disinfectant can be lengthy or inconsistent.

Phenotypic Variation in Clinical S. aureus Isolates Did Not Affect Disinfection Efficacy Using Short-Term UV-C Radiation.

Pigmentation, catalase activity and biofilm formation are virulence factors that cause resistance of Staphylococcus aureus to environmental stress factors including disinfectants. In recent years, automatic UV-C room disinfection gained greater importance in enhanced disinfection procedures to improve disinfection success in hospitals. In this study, we evaluated the effect of naturally occurring variations in the expression of virulence factors in clinical S. aureus isolates on tolerance against UV-C radiation. Quantification of staphyloxanthin expression, catalase activity and biofilm formation for nine genetically different clinical S. aureus isolates as well as reference strain S. aureus ATCC 6538 were performed using methanol extraction, a visual approach assay and a biofilm assay, respectively. Log10 reduction values (LRV) were determined after irradiation of artificially contaminated ceramic tiles with 50 and 22 mJ/cm2 UV-C using a commercial UV-C disinfection robot. A wide variety of virulence factor expression was observed, indicating differential regulation of global regulatory networks. However, no direct correlation with the strength of expression with UV-C tolerance was observed for either staphyloxanthin expression, catalase activity or biofilm formation. All isolates were effectively reduced with LRVs of 4.75 to 5.94. UV-C disinfection seems therefore effective against a wide spectrum of S. aureus strains independent of occurring variations in the expression of the investigated virulence factors. Due to only minor differences, the results of frequently used reference strains seem to be representative also for clinical isolates in S. aureus.

Antibiofilm activity of electrochemically activated water (ECAW) in the control of Salmonella Heidelberg biofilms on industrial surfaces.

Owing to its antimicrobial activity, electrochemically activated water (ECAW) is a potential alternative to chemical disinfectants for eliminating foodborne pathogens, including Salmonella Heidelberg, from food processing facilities. However, their antibiofilm activity remains unclear. This study aimed to evaluate the antibiofilm activity of ECAW against S. Heidelberg biofilms formed on stainless steel and polyethylene and to determine its corrosive capacity. ECAW (200ppm) and a broad-spectrum disinfectant (0.2%) were tested for their antibiofilm activity against S. Heidelberg at 25°C and 37°C after 10 and 20min of contact with stainless steel and polyethylene. Potentiostatic polarization tests were performed to compare the corrosive capacity of both compounds. Both compounds were effective in removing S. Heidelberg biofilms. Bacterial counts were significantly lower with ECAW than with disinfectantin polyethylene, regardless the time of contact. The time of contact and the surface significantly influenced the bacterial counts of S. Heidelberg. Temperature was not an important factor affecting the antibiofilm activities of the compounds. ECAW was less corrosive than the disinfectant. ECAW demonstrated a similar or even superior effect in the control of S. Heidelberg biofilms, when compared to disinfectants, reducing bacterial counts by up to 5 log10 CFU cm-2. The corrosion of stainless steel with ECAW was similar to that of commercial disinfectants. This technology is a possible alternative for controlling S. Heidelberg in the food production chain.

Inactivation of foodborne viruses by novel organic peroxyacid-based disinfectants.

Viruses are responsible for most enteric foodborne illnesses worldwide. The foods most frequently involved are fresh fruits and vegetables since they undergo little or no processing. Washing with a chemical disinfectant is a convenient way of inactivating viruses on foods. Peracetic acid, widely used as a disinfectant in the food industry, has the drawback of leaving a strong odor and is ineffective alone against some foodborne viruses. In this study, four disinfectants, namely per levulinic acid with or without sodium dodecyl sulfate, peracetic acid and a commercial peracetic acid-based disinfectant were tested on murine norovirus 1 (MNV-1), hepatitis A virus (HAV), and hepatitis E virus (HEV). Disinfectant concentrations were 50, 80, 250, 500, and 1000 mg l-1 and contact times were 0.5, 1, 5, and 10 min. Under these conditions, per levulinic acid supplemented with 1% SDS reduced MNV-1 infectious titer by 3 log cycles vs. 2.24 log cycles by peracetic acid within 0.5 min. On stainless steel at 80 ppm, only peracetic acid produced 3-log reductions within 0.5 min. None of these peroxyacids was able to reduce infectious titers of HAV or HEV by even 2 log cycles at any concentration or time-tested. This study will guide the development of new chemical formulas that will be more effective against major foodborne viruses and will have less impact on food quality and the environment.

Effect of Citrus aurantium juice as a disinfecting agent on quality and bacterial communities of striped catfish steaks stored at -20 °C.

Sodium hypochlorite is generally used as a disinfectant in washing of freshwater fishes where the safety aspect of health is of concern. Although plant-based essential oils and synthetic chemical agents have been applied, they might contain toxic substances, are expensive and can cause undesirable quality. This research aims to fill the knowledge gap necessary to validate Citrus aurantium juice as a disinfecting agent for preserving striped catfish steaks at -20 °C for 28 days. Fifty (50) ppm sodium hypochlorite was used as a commercial disinfectant (control). The results showed that a negative color characteristic (higher a* and increased b*) was found in the control but not in striped catfish steaks immersed in C. aurantium juice (TM) on days 14 and 28. No significant differences were found in the peroxide value among the treatments on days 14 and 28 (P > 0.05). A lower accumulation of trichloroacetic acid soluble peptides was detected in TM but not in control, while total volatile basic nitrogen of all treatments was up to standard of fish quality during storage. Contrastingly, the total viable count of both treatments increased to >7.0 log CFU/g on day 28 which did not meet the edible limit of standard for freshwater fishes. The spoilage microbial community was observed on days 0 and 28 of storage which showed a decrease in relative abundance of Acinetobacter, Pseudomonas, Brochothrix, Lactococcus, Carnobacterium, Psychrobacter, and Vagococcus as found in TM on day 28, when compared to the control. Thus, these results implied that C. aurantium juice could replace sodium hypochlorite as an alternative disinfecting agent to control the microbiological spoilage and physico-chemical quality of striped catfish steaks.

Disease incidence, larval parameters and mortality of mulberry silkworm, Bombyx mori L. effected by bed disinfectants

With an aim to find out an effective bed disinfectant regulating disease incidence, larval growth parameters and mortality of mulberry silkworm, Bombyx mori L. revealed a positive influence on the disease incidence, and larval growth of mulberry silkworm race, (CSR6 × CSR26) × (CSR2 × CSR27). The commercial bed disinfectant, Ankush manifested better result in terms of reduction in disease incidence (1.833 %) and larval parameters (larval duration, 21.888 days; full grown larval weight, 4.596 g; silk gland weight, 0.889 g and 24.181% SGTSI) compared to the control (22.667 days, 3.976 g, 0.817 g and 20.726 %, respectively) followed by Sericillin and Turmeric rhizome powder alone or in combinations. However, a combination of bed disinfectants viz., Ankush + Sericillin, Ankush + Turmeric rhizome powder and Sericillin + Turmeric rhizome powder recorded better results compared to Turmeric rhizome powder alone. Though bed disinfectants did not show any significant effect on mortality percentage but Ankush resulted highest reduction of mortality over control (46.933 %). The performance of all the bed disinfectants was found to be better during the late spring season.

The effectiveness of chlorine dioxide gas in portable personal disinfectants to inhibit bacterial growth.

Disinfectants, especially air disinfectants, are necessary to prevent the potential spread of pathogens (bacteria and viruses) in the pandemic era and minimize the spread of pathogens. Some of the commercial disinfectant products that are often used generally contain chlorine dioxide (ClO2) gas. This study tested the effectiveness of two different commercial disinfectants, a liquid stick disinfectant and a powder disinfection card, to carry out the disinfection of pathogenic bacteria in the environment. These two disinfectants were used as a medium for releasing chlorine dioxide gas which has a much stronger bactericidal effect. In the form of liquid stick, ClO2 is more effective in the disinfection process rather than in the form of powder. The effectiveness of the liquid disinfectant in inhibiting the growth of pathogenic bacteria is influenced by the temperature and the area of the open space covered. Considering that the release from both disinfectants used is very small (0.002 ppmv/h), it takes a small area to ensure that the disinfection process runs effectively.

Antimicrobial Activity of Cosmos caudatus Against Staphylococcus aureus and Escherichia coli.

Malaysia is known for its richness in ecosystem including medicinal plants and herbs. The use of traditional herbs for medical purposes has been practiced for ages without any proper understanding on how they work. This study aims to produce extract from the leaves of Cosmos caudatus (Ulam Raja) and to investigate the antimicrobial activity of the produced extract against Staphylococcus aureus and Escherichia coli. Ethanolic Soxhlet extraction was carried out to obtain the leaves extract. Product from extraction process was subsequently tested using the Kirby-Bauer disk diffusion test to determine its inhibitory effects against S. aureus and E. coli. Finally, the bioactive compounds in extracts were profiled using gas chromatography coupled with mass spectrometer (GC-MS). Findings showed ethanol is suitable to be used in obtaining extract from the leaves of C. caudatus. The extract produced was dark green and was able to inhibit the growth of both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria. The size of inhibition zones ranging from 22 to 24 mm. The zones of inhibition produced by C. caudatus extract in this study are comparable to commercial antiseptic tested simultaneously in the experiment. Analysis of extract using GC-MS revealed several bioactive compounds including palmitic acid, stigmasterol, phytol and neophytadiene These compounds are well known for their medicinal and therapeutic properties such as antimicrobial, antioxidants and antitumor. Additionally, these bioactive compounds are commonly used as ingredients in commercial antiseptics and disinfectants. This study therefore has proven the medicinal properties of C. caudatus. Findings from this study can be used to develop plant-based pharmaceutical products which are cheaper, safer, and more environmentally friendly.

In Vitro Investigation of the Antibacterial Activity of Nine Commercial Water Disinfectants, Acidifiers, and Glyceride Blends against the Most Important Poultry Zoonotic Bacteria.

Identifying and monitoring the efficiency of alternative biocides that are presently used in livestock is gaining vast attention. The objective of this study was to determine, in vitro, the antibacterial activity of nine commercial water disinfectants, acidifiers, and glyceride blends against clinical isolates or reference strains of zoonotic pathogens belonging to the genera Escherichia spp., Salmonella spp., Campylobacter spp., Listeria spp., and Staphylococcus spp. For each product, the antibacterial activity was tested in concentrations ranging from 0.002 to 1.136% v/v and expressed as the minimum concentration of the product that inhibits bacterial growth (MIC). Water disinfectants Cid 2000™ and Aqua-clean® recorded MICs ranging from 0.002 to 0.142% v/v, while the lowest MICs were recorded at two strains of Campylobacter (0.002-0.004% v/v). Virkon® S displayed various MICs (0.013-0.409% w/v) and was highly effective at suppressing the growth of Gram-positive bacteria such as S. aureus (0.013-0.026% w/v). The MICs of water acidifiers (Agrocid Super™Oligo, Premium acid, and Ultimate acid) and glyceride blends (CFC Floramix, FRA®LAC34, and FRA®Gut Balance) ranged from 0.036 to 1.136% v/v, and for most of these products, MICs were closely correlated by their ability to modify the pH of the culture medium close to 5. In conclusion, most of the tested products showed promising antibacterial activity; as a result, they would be good candidates for pathogen control in poultry farms and for reducing the emergence of antimicrobial resistance. However, further in vivo studies are recommended to provide relevant information for the underlying mechanisms, as well as for the establishment of the optimal dosage scheme for each product and their possible synergies.

Characterization of structure isomers of ethylbenzalkyl dimethyl ammonium chlorides and quantification in commercial household disinfectant products

Characterization of structure isomers of ethylbenzalkyl dimethyl ammonium chlorides and quantification in commercial household disinfectant products

Far-UVC Radiation for Disinfecting Hands or Gloves?

(1) Background: Far-UVC radiation in the spectral range 200-230 nm has, according to previous findings, a strong antimicrobial effect on pathogens, but exhibits hardly any harmful effect on human skin. Therefore, the present study will discuss whether such radiation could also be suitable for hand disinfection in the healthcare sector. (2) Methods: Hands and gloves were microbially contaminated and exposed to radiation from a 222 nm krypton-chloride-excimer lamp. The applied doses were 23 mJ/cm2 and 100 mJ/cm2, respectively. Irradiated and non-irradiated hands and gloves were pressed onto agar plates and colonies were counted and compared after 24 h of incubation. For comparison, we also treated hands and gloves with a commercial liquid alcohol-based disinfectant. (3) Results: On the hand, the 23 mJ/cm2 resulted in the reduction of the observed colonies on the agar plates by one log level. For the gloves irradiated with 100 mJ/cm2, a colony reduction of 1.3 log levels was recorded. In the comparative experiments with the commercial disinfectant, a colony reduction of 1.9 and approximately one log level was observed on hand and gloves, respectively. (4) Conclusion: In both cases, far-UVC radiation provided a considerable reduction in microorganisms. However, compared to published far-UVC irradiation results in suspensions, the disinfection success on hands and gloves was rather low. With regard to the irradiation limits currently existing in the European Union, multiple daily hand disinfection with far-UVC radiation is actually legally not possible at present, but the thresholds are currently under discussion and could change in the future. Far-UVC disinfection of hands in gloves seems theoretically possible if attention is paid to potential perforations in the gloves.

The potential of biomass-derived bio-liquid to prevent the spread of SARS-CoV-2 from waste and its production-based life cycle assessment

COVID-19 pandemic caused a significant increase in medical and infected domestic waste, greatly increasing risk of human infected with SARS-CoV-2. Therefore, it is critical to prevent the spread of SARS-CoV-2 from solid waste to humans. Current commercial disinfectants present a high carbon footprint issue. Hence, we prepared a renewable wheat straw-based bio-liquid that can damage SARS-CoV-2 RNA and protein. The wet thermochemical extraction (WTE) bio-liquid, with total organic carbon concentration exceeding 1892 mg/L, could effectively damage the virus. However, dry thermochemical extraction (DTE) samples were not efficient due to their low content of effective compounds. The life cycle assessment showed that WTE bio-liquid production implies lower energy and environmental negative impacts than DTE. Moreover, the process by-product, char, can simultaneously reduce 3.1 million tonnes of global CO2 emissions while used as coal substitute. Yield of bio-liquid extremely exceed commercial disinfectant with just 1 % wheat straw utilisation, which meet the demand of processing solid waste. Further, their costs are significantly lower than commercial disinfectants, which are suitable for developing countries. Therefore, the antiviral bio-liquid produced from agricultural straw can be a new way to meet the needs of preventing the spread of SARS-CoV-2 and resume the sustainable development of society.

Antibacterial Activities of Biosynthesized Zinc Oxide Nanoparticles and Silver-Zinc Oxide Nanocomposites using Camellia Sinensis Leaf Extract

Green route of nanomaterials synthesis is increasing in demand due to ecofriendly to the environment. In this research, objective is to biosynthesize and evaluate the antibacterial performance of pure ZnO and Ag/ZnO nanocomposites using Camellia sinensis leaf extracts. Pure ZnO nanoparticles and Ag/ZnO nanocomposites were synthesized using Camellia sinensis leaf extract. The antibacterial effectiveness against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria were examined and compared with 1 % Chlorox as a commercial disinfectant by well diffusion method based on the zone of inhibition. Pure ZnO nanoparticles and Ag/ZnO nanocomposites had hexagonal shape ZnO nanoparticles and rectangular shape Ag nanoparticles in Ag/ZnO nanocomposites with a particle crystal size between 20 - 30 nm with carboxylic and phenolic functional group attached on it. Ag/ZnO nanocomposites exhibited antibacterial effectiveness against both gram-positive and gram-negative bacteria, while pure ZnO nanoparticles exhibited antibacterial effectiveness against only gram-positive bacteria. Conversely, 1 % Chlorox and 1 % DMSO showed no significant antibacterial activity against gram-positive and gram-negative bacteria. Camellia sinensis mediated ZnO and Ag/ZnO nanoparticles showed antibacterial potential against S. aureus and E. coli suggesting that green route to synthesis of antibacterial nanoparticles can be an excellent strategy to develop eco-friendly disinfectant products HIGHLIGHTS Zinc oxide nanocomposites biosynthesis by Camellia sinensis at low pH, Antibacterial properties of ZnO nanoparticles and Ag/ZnO nanocomposites on Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538P strains, Disinfection application. GRAPHICAL ABSTRACT

Household spices and minerals as alternative disinfectants for mobile phones

Mobile phones play an essential role in enhancing personal, social, and professional life in many ways, including to access to communication, information, and entertainment. However, mobile phones also come in contact with environments containing high densities of microorganisms, such as hospitals, schools, restrooms, and kitchens, suggesting that mobile phones could also act as carriers of disease. Commercial disinfectants are highly effective against potential human pathogens found on mobile phones, yet these disinfectants also contain chemicals that are toxic to both human health and the environment. In addition, there is evidence that modern microorganisms are becoming resistant to commercially available disinfectants. We hypothesized that household spices and minerals, such as garlic, mint, zinc, and iron, could act as alternate solutions for disinfecting mobile phones after daily use. Our results demonstrate that garlic, iron, and zinc are just as effective at suppressing microorganisms compared to commercially available cleaners, Clorox and Pine-Sol. These results could help guide further research aimed at producing more environmentally friendly cleaners and reducing the need for toxic chemicals in household disinfectants.