Sherif Abd-Elmaksoud

Effective hand washing takes time and hand sanitizers that contain alcohol have a number of drawbacks, and frequent use of alcohol may cause skin damage. The objective of this study is to formulate nanostructured lipid carrier systems containing chlorhexidine digluconate to be applied topically for hand hygiene, especially for people sensitive to alcohol. A cytotoxicity experiment was conducted to ascertain the safe dosage for each of the three nano-cream formulas (F1, F2 and F3). Following each treatment, the viral titer was assessed using tissue culture infectious dose₅₀ and standard plaque assays. The selected formulation was characterized rheologically. Furthermore, fifteen volunteers of various ages and genders participated in the vivo antimicrobial test of the selected formulation as a hand sanitizer. All of the formulas were found to be safe. Using the disc diffusion method, the three formulations exhibited in vitro antimicrobial effects against different microbes. F1 showed biphasic release, reasonable skin deposition and spherical droplets under a microscope. F1 exhibited a non-Newtonian shear thinning flow behavior. After 30 min, the reduction values for rotavirus and Phix-174 were 21 and 4%, respectively. Additionally, the impact of F1 was assessed on the infectivity of simian rotavirus sa-11 (ds RNA) and Phix-174 (ss DNA) bacteriophage. According to the findings of the in vivo study, the percentage of total bacterial counts that were removed varied from 91 to 100%. Moreover, the range of the removal percentage of total fungi was 95.38 to 100%. In summary, F1 can be used as an economic, safe, and effective hand antiseptic. It can also completely replace alcohol in the market.

Nonthermal plasma (NTP) and plasma‐activated water (PAW) are emerging nonthermal technologies for microbial decontamination of fresh vegetable and fruit products. Yet, their efficacy is strongly influenced by microbial type and matrix complexity. This study evaluated the antimicrobial performance of NTP and PAW against two foodborne bacterial pathogens, namely Salmonella Typhimurium ( S. Typhimurium ) and Listeria monocytogenes ( L. monocytogenes ), as well as bacteriophage ΦX174 as a viral surrogate. The effects of NTP and PAW were studied on two fresh produce surfaces of Eruca sativa (arugula) and Fragaria ananassa Duch (strawberry) in aqueous suspensions. The OES confirmed the generation of reactive oxygen and nitrogen species (ROS/RNS) with high electron density. In water, direct NTP achieved rapid inactivation of bacterial pathogens (> 5 log ₁₀ within 2–3 min), whereas efficacy on produce surfaces was reduced, with maximum reductions of ~2.5 log ₁₀ on arugula and ~2 log ₁₀ on strawberries, while higher reductions (> 5 log ₁₀ ) were observed in the corresponding aqueous phase. In contrast, PAW demonstrated strong bactericidal activity in aqueous systems (up to ~4.9 log ₁₀ ) and on produce surfaces, achieving ~2.5 log ₁₀ reduction on arugula and ~3.1 log ₁₀ on strawberries for S. Typhimurium . However, viral inactivation was more limited and matrix‐dependent, with PAW achieving ~2.3 log ₁₀ reduction on arugula but only ~0.5 log ₁₀ on strawberries. The scanning electron microscopy (SEM) revealed severe membrane damage to the selected bacterial pathogens after treatment and microbial localization within the produce surface pores, explaining matrix‐associated protection. Overall, NTP and PAW show strong potential to enhance the safety of fresh produce, but further optimization is needed to overcome surface shielding and preserve product quality.

Recently, hand sanitization has gained attention for preventing disease transmission. Many on-the-market convenient dermal sanitizers contain alcohol, which can be detrimental to the skin. Therefore, three nanoemulgel formulations (LN-F1, LN-F2, LN-F3) incorporating lemon peel extract (LE), and with various increasing concentrations of xanthan gum as a gelling agent and stabilizer, were developed and characterized as a novel alternative. All formulations showed non-Newtonian shear-thinning flow behavior, particle size values below 200 nm, and increasing zeta potential with higher xanthan gum concentrations. All nanoemulgel formulations exhibited greater in vitro phenolic compound release than free LE. LN-F2 (1.0% LE, 20.0% mineral oil, 20.0% Span 80, 4.0% Cremophor RH 40, 4.0% PEG 400, 0.5% xanthan gum, 50.5% dH₂O) was selected as the optimal formulation due to improved characteristics. LE and LN-F2 potential cytotoxicity was assessed on MA-104, showing no significant cellular morphological alterations up to 10 mg/mL for both samples. LN-F2 showed in vitro antimicrobial activity against E. coli, S. Typhimurium, P. aeruginosa, S. aureus, L. monocytogenes, and C. albicans, as well as antiviral activity against phiX 174, but no effect against rotavirus (SA-11). In vivo, LN-F2 presented a removal capacity of 83% to 100% for bacteria and 89% to 100% for fungi. These findings suggest that the formulated nanoemulgel holds potential as a safe and effective antiseptic, providing a viable alternative to commercial alcohol-based formulations.

Innovative technologies are needed to enhance access to clean water and avoid waterborne diseases. We investigated the performance of cold atmospheric plasma (CAP), a clean and sustainable approach for microbial inactivation and total organic carbon (TOC) degradation in environmental water. Water matrices played a crucial role in the performance of CAP efficacy; for example, complete removal of ɸX174 from dH₂O required 1 min of treatment, while ɸX174 reductions of ~ 2log₁₀ and 4log₁₀ were obtained after 10 min of CAP exposure in river water and wastewater samples, respectively. Similarly, after 10 min of CAP treatment, bacterial concentrations decreased by 3 log₁₀ and 4 log₁₀, in river and wastewater samples, respectively. In contrast, after 30 s of contact time, a 4 log₁₀ reduction of bacteria was accomplished in dH₂O. Complete removal of Acanthamoeba from dH₂O was found after 30 min of CAP treatment, whereas it was not removed from surface water or wastewater at the same exposure time. Additionally, the approach successfully reduced TOC, and the degradation kinetics of TOC were represented by pseudo-first-order. CAP showed higher rates of TOC degradation in the final effluent of the wastewater treatment plant compared to surface water. The difference in CAP performance between river water and wastewater could be attributed to the bulk structure of humic acids in river water compared to small organic byproducts in the final effluent of WWTP. Overall, the findings reported here support the idea that CAP holds promise as a sustainable solution for controlling pathogens, removing organic water pollution, and integrating with traditional purification processes. Low-cost systems may advance CAP technology and increase its widespread use.

This study evaluates the efficiency of a sustainable technology represented in an integrated pilot-scale system, which includes a facultative pond (FP), a high-rate algal pond (HRAP), and a rock filter (RF) for wastewater treatment to produce water that complies with the Egyptian standards for treated wastewater reuse. Still, limited data are available on pathogen removal through HRAP systems. Thus, in this study, the performance of the integrated system was investigated for the removal of Escherichia coli (E. coli), coliform bacteria, eukaryotic pathogens (Cryptosporidium spp., Giardia intestinalis, and helminth ova), somatic coliphages (SOMCPH), and human adenovirus (HAdV). Furthermore, physicochemical parameters were determined in order to evaluate the performance of the integrated system. The principal component analysis and non-metric multidimensional scaling analysis showed a strong significant effect of the integrated system on changing the physicochemical and microbial parameters from inlet to outlet. The mean log₁₀ removal values for total coliform, fecal coliform, and E. coli were 5.67, 5.62, and 5.69, respectively, while 0.88 log₁₀ and 1.65 log₁₀ reductions were observed for HAdV and SOMCPH, respectively. The mean removal of Cryptosporidium spp. and Giardia intestinalis was 0.52 and 2.42 log₁₀, respectively. The integrated system achieved 100% removal of helminth ova. The results demonstrated that the system was able to improve the chemical and microbial characteristics of the outlet to acceptable levels for non-food crops irrigation. Such findings together with low operation and construction costs of HRAPs should facilitate wider implementation of these nature-based systems in remote and rural communities. Overall, this study provides a novel insight into the performance of such systems to eliminate multiple microbial pathogens from wastewater.

Here, we studied the effect of cold atmospheric plasma (CAP) on chemical and microbial pollutants. A model compound for organic water pollutants, crystal violet dye (CV), was used as a chemical probe to monitor a rapid change in the reactive oxygen and nitrogen species (ROS/RNS) in water. We used a point electrode to generate plasma above the treated liquid. Three variables (the gap distance between the point electrode and the water surface, the input voltage, and the water thickness below the point electrode) have been studied to show their effects on CV percent removal as a response. Additionally, the microbicidal effect of CAP against rotavirus (RoV), φX174, E. coli , and S. aureus in water was investigated. A rapid virucidal activity was observed, up to 5 log ₁₀ reduction in 1 min for φX174 and 4.3 log ₁₀ reduction of RoV in 5 min CAP exposure. Viral removal could be due to the fact that plasma produced active species which have an oxidative effect on viral capsid protein. As expected, bacteria were more sensitive to CAP than viruses, as ∼4log ₁₀ removal was observed after 30s exposure. The potent antibacterial effect of CAP could be due to the reaction of free radicals with the outer membrane of bacteria or even the penetration of the bacterial cells. CAP has the potential to control microbial and chemical pollution in water. However, further work should be conducted to determine the efficacy of CAP treatment in complex water matrices.

The buffalo green monkey (BGM) cell line is required for the detection of enteric viruses in biosolids through a total culturable viral assay (TCVA) by the United States Environmental Protection Agency. In the present study, BGM and PLC/PRF/5 cell lines were evaluated for TCVA and for their use in determining the incidence of adenoviruses and enteroviruses in raw sludge and Class B biosolids. Six raw sludge and 17 Class B biosolid samples were collected from 13 wastewater treatment plants from seven U.S. states. Samples were processed via organic flocculation and concentrate volumes equivalent to 4 g total solids were assayed on BGM and PLC/PRF/5 cells. Cell monolayers were observed for cytopathic effect (CPE) after two 14-days passages. Cell lysates were tested for the presence of adenoviruses and enteroviruses by PCR or RT-PCR. The PLC/PRF/5 cells detected more culturable viruses than the BGM cells by CPE (73.9% vs. 56.5%, respectively). 52% of the samples were positive for CPE using both cell lines. No viruses were detected in either cell line by PCR in flasks in which CPE was not observed. No adenoviruses were detected in 13 CPE-positive samples from BGM lysates. In contrast, of the 17 samples exhibiting CPE on PLC/PRF/5 cells, 14 were positive for adenoviruses (82.4%). In conclusion, PLC/PRF/5 cells were superior for the detection of adenoviruses in both raw sludge and Class B biosolids. Thus, the use of BGM cells alone for TCVA may underestimate the viral concentration in sludge/biosolid samples.

Norovirus accounts for a large portion of the gastroenteritis disease burden, and outbreaks have occurred in a wide variety of environments. Understanding the role of fomites in norovirus transmission will inform behavioral interventions, such as hand washing and surface disinfection. The purpose of this study was to estimate the contribution of fomite-mediated exposures to infection and illness risks in outbreaks. A simulation model in discrete time that accounted for hand-to-porous surfaces, hand-to-nonporous surfaces, hand-to-mouth, -eyes, -nose, and hand washing events was used to predict 17 hr of simulated human behavior. Norovirus concentrations originated from monitoring contamination levels on surfaces during an outbreak on houseboats. To predict infection risk, two dose-response models (fractional Poisson and ₂F₁ hypergeometric) were used to capture a range of infection risks. A triangular distribution describing the conditional probability of illness given an infection was multiplied by modeled infection risks to estimate illness risks. Infection risks ranged from 70.22% to 72.20% and illness risks ranged from 21.29% to 70.36%. A sensitivity analysis revealed that the number of hand-to-mouth contacts and the number of hand washing events had strong relationships with model-predicted doses. Predicted infection risks ranged from 21.29% to 70.36%, overlapping with leisure setting and environmental attack rates reported in the literature. In the outbreak associated with the viral concentrations used in this study, attack rates ranged from 50% to 86%. This model suggests that fomites may have accounted for 25% to 82% of illnesses in this outbreak. Fomite-mediated exposures may contribute to a large portion of total attack rates in outbreaks involving multiple transmission modes. The findings of this study reinforce the importance of frequent fomite cleaning and hand washing, especially when ill persons are present.

Aims Quantitative data on the doses needed to inactivate microorganisms on fomites is not available for ultraviolet applications. The goal of this study was to determine the doses of UV light needed to reduce bacteria and murine norovirus on hard surface fomites through experimentation and to identify appropriate models for predicting targeted levels of reduction. Methods and results Stainless steel and Formica laminate coupons were selected as they are common surfaces found in healthcare settings. Test organisms included methicillin‐resistant Staphylococcus aureus (MRSA), vancomycin‐resistant Enterococcus (VRE), Clostridium difficile and murine norovirus. The fomites were inoculated with 10⁵ to 10⁷ bacteria or virus and exposed to a range of UV doses. The order of resistance to UV irradiation was virus, bacterial spore and vegetative cell. The best fitting inactivation curves suggested non‐linear responses to increasing doses after a 3 to 4 log reduction of the test organisms. The average UV doses required for 3 log reduction of the C .difficile, MRSA and VRE were 16,000, 6,164 and 11,228 (mJ‐s/cm²) for stainless steel, respectively and 16,000, 11,727 and 12,441 (mJ‐s/cm²) for Formica laminate respectively. Conclusion Higher UV light doses are required to inactivate bacteria and viruses on hard surfaces than in suspension. Greater doses are needed to inactivate bacterial spores and murine norovirus compared to vegetative bacteria.