Antibiotics Susceptibility Phenotyping and Extracellular Polymeric Substances Production of Listeria monocytogenes Biofilm and Planktonic Cells

ABSTRACT The present research aimed to compare the susceptibility of L. monocytogenes planktonic cells and three different ages (10, 40 and 90 days-old) of biofilm to antibiotics. A second objective was to determine the relationship between the amount of produced EPS by L. monocytogenes biofilm and antibiotic susceptibility of L. monocytogenes biofilm. The extraction of EPS was carried out by using a cation exchange resin method and exopolysaccharides content in crude EPS was determined using phenol-sulfuric acid method. Antibiotic susceptibility of L. monocytogenes biofilm and planktonic cells were performed by the standard disk diffusion method. The maximum amount of exopolysaccharides was determined (411.5µg/cm 2 ) in 90 days-old L. monocytogenes biofilm collected from iron pipe. While, the minimum amount (203.4µg/cm 2 ) was in Cu pipe. Regarding to the antibiotic susceptibility results, it was found that, L. monocytogenes plankton cells were more sensitive to the tested antibiotic than L. monocytogenes biofilm. Also, it was found that, 90 days-old L. monocytogenes biofilm collected from iron pipe was more resistant to all tested antibiotics than which collected from Cu pipe. The findings in this research provide useful information and background data on the role of EPS in antibiotic resistance of L. monocytogenes biofilm

Sustainable municipal wastewater treatment using an innovative integrated compact unit: microbial communities, parasite removal, and techno-economic analysis

Abstract Background The upflow anaerobic sludge blanket (UASB) reactors rely on bacterial communities to break down pollutants in wastewater (municipal or industrial). Methods and results In this study, a novel combination of UASB followed by aerobic treatment has been proposed for the treatment of municipal wastewater focusing on bacterial communities using high-throughput sequencing and parasite removal in this novel combination of reactors. Moreover, economic estimation of the compact unit composed of two overlapping UASB reactors, followed by a downflow hanging non-woven fabric (DHNW) reactor, the anaerobic baffled reactor (ABR), and chlorine unit was investigated in this study based on community populations of 1000 and 10,000 inhabitants, with a municipal plant capacity of 54,000 and 540,000 m3/year. Cost estimation was conducted based on two scenarios, one considering the contingency cost and auxiliary facility, and the other excluding them. Non-metric multidimensional scaling (nMDS) revealed that the treatment stages structured the microbial communities. Proteobacteria was the most prevalent phylum in all treatment stages, followed by Bacteroidota in most stages. Firmicutes and Actinobacteria were also present in significant amounts. The treatment system achieved from 40 to 66.67% removal of parasites (parasitic nematode, Cryptosporidium, and microsporidia). Redundancy analysis (RDA) indicated a strong positive correlation between chemical and biological oxygen demand (COD/BOD) with Campylobacterales and could be used as a bioindicator of treatment performance. Conclusion These findings can inform the development of more efficient and sustainable wastewater treatment systems that take into account microbial ecology and economic considerations

Formulation and Characterization of Non-Toxic, Antimicrobial, and Alcohol-Free Hand Sanitizer Nanoemulgel Based on Lemon Peel Extract

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

Pathogens Removal in a Sustainable and Economic High-Rate Algal Pond Wastewater Treatment System

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

Bioactive Azadirachta indica and Melia azedarach leaves extracts with anti-SARS-CoV-2 and antibacterial activities.

The leaves of Azadirachta indica L. and Melia azedarach L., belonging to Meliaceae family, have been shown to have medicinal benefits and are extensively employed in traditional folk medicine. Herein, HPLC analysis of the ethyl acetate fraction of the total methanolic extract emphasized the enrichment of both A. indica L., and M. azedarach L. leaves extracts with phenolic and flavonoids composites, respectively. Besides, 4 limonoids and 2 flavonoids were isolated using column chromatography. By assessing the in vitro antiviral activities of both total leaves extracts against Severe Acute Respiratory Syndrome Corona virus 2 (SARS-CoV-2), it was found that A. indica L. and M. azedarach L. have robust anti-SARS-CoV-2 activities at low half-maximal inhibitory concentrations (IC50) of 8.451 and 6.922 μg/mL, respectively. Due to the high safety of A. indica L. and M. azedarach L. extracts with half-maximal cytotoxic concentrations (CC50) of 446.2 and 351.4 μg/ml, respectively, both displayed extraordinary selectivity indices (SI>50). A. indica L. and M. azedarach L. leaves extracts could induce antibacterial activities against both Gram-negative and positive bacterial strains. The minimal inhibitory concentrations of A. indica L. and M. azedarach L. leaves extracts varied from 25 to 100 mg/mL within 30 min contact time towards the tested bacteria. Our findings confirm the broad-spectrum medicinal value of A. indica L. and M. azedarach L. leaves extracts. Finally, additional in vivo investigations are highly recommended to confirm the anti-COVID-19 and antimicrobial activities of both plant extracts