Bactericidal activity of biosynthesized silver nanoparticles against human pathogenic bacteria

Green synthesis is an attractive and eco-friendly approach to generate potent antibacterial silver nanoparticles (Ag-NPs). Such particles have long been used to fight bacteria and represent a promising tool to overcome the emergence of antibiotic-resistant bacteria. In this study, green synthesis of Ag-NPs was attempted using plant extracts of Aloe vera, Portulaca oleracea and Cynodon dactylon. The identity and size of Ag-NPs was characterized by ultraviolet–visible spectrophotometer and scanning electron microscopy. Monodispersed Ag-NPs were produced with a range of different sizes based on the plant extract used. The bactericidal activity of Ag-NPs against a number of human pathogenic bacteria was determined using the disc diffusion method. The results showed that Gram positive bacteria were more susceptible than Gram negative ones to these antibacterial agents. The minimum inhibitory concentration was determined using the 96-well plate method. Finally, the mechanism by which Ag-NPs affect bacteria was investigated by SEM analysis. Bacteria treated with Ag-NPs were seen to undergo shrinkage and to lose their viability. This study provides evidence for a cheap and effective method for synthesizing potent bactericidal Ag-NPs and demonstrates their effectiveness against human pathogenic bacteria

Molecular identification of adenoviruses associated with respiratory infection in Egypt from 2003 to 2010.

BACKGROUND: Human adenoviruses of species B, C, and E (HAdV-B, -C, -E) are frequent causative agents of acute respiratory infections worldwide. As part of a surveillance program aimed at identifying the etiology of influenza-like illness (ILI) in Egypt, we characterized 105 adenovirus isolates from clinical samples collected between 2003 and 2010. METHODS: Identification of the isolates as HAdV was accomplished by an immunofluorescence assay (IFA) and confirmed by a set of species and type specific polymerase chain reactions (PCR). RESULTS: Of the 105 isolates, 42% were identified as belonging to HAdV-B, 60% as HAdV-C, and 1% as HAdV-E. We identified a total of six co-infections by PCR, of which five were HAdV-B/HAdV-C co-infections, and one was a co-infection of two HAdV-C types: HAdV-5/HAdV-6. Molecular typing by PCR enabled the identification of eight genotypes of human adenoviruses; HAdV-3 (n = 22), HAdV-7 (n = 14), HAdV-11 (n = 8), HAdV-1 (n = 22), HAdV-2 (20), HAdV-5 (n = 15), HAdV-6 (n = 3) and HAdV-4 (n = 1). The most abundant species in the characterized collection of isolates was HAdV-C, which is concordant with existing data for worldwide epidemiology of HAdV respiratory infections. CONCLUSIONS: We identified three species, HAdV-B, -C and -E, among patients with ILI over the course of 7 years in Egypt, with at least eight diverse types circulating

Ozonation of carbamazepine, diclofenac, sulfamethoxazole and trimethoprim and formation of major oxidation products

The degradation of four pharmaceuticals, carbamazepine (CBZ), diclofenac (DCF), sulfamethoxazole (SMX) and trimethoprim (TMP) by ozonation was studied under a range of experimental conditions, including ozone dosage and concentration of target compounds. The concentration profile of the pharmaceuticals and detection of any by-products formed was carried out using liquid chromatography mass spectrometry. CBZ, DCF, TMP and SMX at initial concentration of 5 mg/L each were degraded to below the method detection limit (1 μg/L) when they reacted with 1.6, 2.3, 2.8 and 4.5 mg/L of ozone, respectively. For each parent compound several by-products were detected after the ozone treatment. A number of these by-products have not been previously reported in the literature. Some of these by-products were founds to be quite resistant to ozone up to applied ozone dosages of 15 mg/L

Photolysis and UV/H<inf>2</inf>O<inf>2</inf> of diclofenac, sulfamethoxazole, carbamazepine, and trimethoprim: Identification of their major degradation products by ESI–LC–MS and assessment of the toxicity of reaction mixtures

© 2017 Institution of Chemical Engineers The photolysis of diclofenac (DCF), sulfamethoxazole (SMX), carbamazepine (CBZ), and trimethoprim (TMP) was investigated using a low-pressure (LP) mercury ultraviolet (UV) lamp (254 nm) and a combination of UV with hydrogen peroxide (H2O2). For each experiment, 5 mg/L of each pharmaceutical was prepared in pure water and individually degraded by either UV alone or UV/H2O2. DCF and SMX were highly susceptible to UV treatment and completely degraded to below their LC–MS detection limit (1 μg/L) after only 8 min of UV irradiation. TMP and CBZ were more resistant to UV treatment, with only 58.2 and 25.2% degradation (after 1 h UV exposure). The combination of H2O2 addition (up to 0.2 g/L) with UV significantly improved the removal rate of TMP and CBZ up to 91.2 and 99.7% of the initial concentration, respectively. A number of novel transformation compounds were identified as UV or UV/H2O2 degradation products using LC–MS. The range and amount of these transformation compounds strongly depended on the applied treatment conditions. The toxicity of each pharmaceutical solution before and after treatment was also evaluated and all parent compounds were non-toxic at the tested concentration (i.e. 5 mg/L). DCF, in particular, but also CBZ and SMX, showed an increase in solution toxicity after treatment with UV only, indicating the presence of photolytic degradation products that are more toxic than the parent compounds. Treatment with UV/H2O2 reduced the toxicity of all solutions to below the detection limit of the assay

Degradation of diclofenac, trimethoprim, carbamazepine, and sulfamethoxazole by laccase from Trametes versicolor: Transformation products and toxicity of treated effluent

© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. The degradation of diclofenac (DCF), trimethoprim (TMP), carbamazepine (CBZ), and sulfamethoxazole (SMX) by laccase from Trametes versicolor was investigated. Experiments were conducted using the pharmaceuticals individually, or as a mixture at different initial concentrations (1.25 and 5 mg/L each). The initial enzymatic activity of all the treated samples was around 430–460 U(DMP)/L. The removal of the four selected pharmaceuticals tested individually was more effective than when tested in mixtures under the same conditions. For example, 5 mg DCF/L was completely removed to below its detection limit (1 µg/L) within 8 h in the individual experiment vs. after 24 h when dosed as a mixture with the other pharmaceuticals. A similar trend was visible with other three pharmaceuticals, with 95 vs. 39%, 82 vs. 34% and 56 vs. 49% removal after 48 h with 5 mg/L of TMP, CBZ, and SMX tested individually or as mixtures, respectively. In addition, at the lower initial concentration (1.25 mg/L each), the removal efficiency of TMP, CBZ, and SMX in mixtures was lower than that obtained at the higher initial concentrations (5 mg/L each) during both the individual and combined treatments. Four enzymatic transformation products (TPs) were identified during the individual treatments of DCF and CBZ by T. versicolor. For TMP and SMX, no major TPs were observed under the experimental conditions used. The toxicity of the solution before and after enzymatic treatment of each pharmaceutical was also assessed and all treated effluent samples were verified to be non-toxic