Sulphatroxazole [HRP]

The influence of the iron precursor salt on the preparation of Carbon-Fe catalysts was evaluated based on the generation of (OH)-O-center dot radicals in a heterogeneous Fenton process applied to the degradation of sulfamethoxazole (SMX). Carbon catalysts were obtained with 9% Fe by weight using three iron salts: iron acetate (C-AC-AFe), iron sulfate (C-AC-SFe) and iron nitrate (C-AC-NFe). Characterization of catalysts was evaluated by N-2 physisorption, X-ray diffraction, scanning electron microscopy and spectroscopic techniques (FTIR, EDX, XPS); these properties were related to the (OH)-O-center dot generation kinetics and to SMX degradation rate. The iron precursor salt favors the anchoring of the metal in different oxidation state on the catalyst in a proportion of: Fe2+ / Fe3+= 4.1 for C-ACAFe, 1.5 for C-AC-SFe and 1.7 for C-AC-NFe, which is related to the (OH)-O-center dot generated: 53.8 mu M g(-1), 37.9 mu M g(-1) and 42.4 mu M g(-1), respectively. The (OH)-O-center dot generation kinetics were described by a pseudo-first-order model with rate constants of 0.0252 and 0.0299 min(-1) for C-AC-AFe and C-AC-SFe respectively, which coincide with the kinetic constants for the degradation of SMX (0.0262 and 0.0297 min(-1)), therefore, the oxidation process is carried out by (OH)-O-center dot. In the case of C-AC-NFe, Fe was fixed within the texture of the carbon and the (OH)-O-center dot generation was the lowest (0.0005 min(-1)), explaining the reaction is limited by diffusion. For SMX, the degradation percentage achieved for 20 mg L-1 was: 98.2 % in 120 min for C-AC-AFe, 98.1 % in 180 min for C-AC-SFe and 92.8 % in 210 min for C-AC-NFe.

Objectives: In Iran, pigeons are kept and bred on the roofs of houses, which indicates the potential significance of pigeons in the dispersal of antimicrobial resistant Escherichia coli strains. Here we characterized antimicrobial resistance genotypes in relation to phenotypic presentations and phylogenetic backgrounds of the E. coli isolates from household pigeons in Kerman in southeast Iran. Methods: Totally, 152 faecal E. coli isolates from domestic and household pigeons were screened for 13 antimicrobial resistance genes, bla(TEM), bla(SHV), bla(CTX-M), sulI, sulII, dhfrI, dhfrV, aadA, aac(3)-I, tetA, tetB,floR and qnrA, by conventional polymerase chain reaction (PCR) technique. Clermont phylogenetic background of E. coli strains was studied and antibiotic resistance of all strains was assessed for seven antibiotics. Results: The antimicrobial resistance genes bla mm, tetA, tetB and aadA were detected in 52.6%, 6.5%, 6.5% and 5.9% of the isolates, respectively. PCR phylotyping revealed that a significant number of isolates within A(0) (54%), A(1) (70%), B1 (57.6%), B2(2) (75%) and D1 (87.5%) phylogroups were positive for the studied resistance genes. One phenotypic resistance pattern (trimethoprim-sulfamethoxazole) was associated with the presence of the corresponding gene sul2. Conclusions: An alarming rate of phenotypic resistance was observed in this study. Many isolates were positive for the screened resistance genes. According to the phylogenetic background, most resistant isolates belonged to the commensal phylotypes, representing significant role of commensal strains as a source of resistance genes. These findings highlight the role of the pigeon as disseminator of resistant E. coli strains. (C) 2020 The Authors. Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.