Insight into antibiotics removal: Exploring the photocatalytic performance of a Fe3O4/ZnO nanocomposite in a novel magnetic sequential batch reactor.

The purpose of this research was the preparation and photocatalytic evaluation of a novel nanocomposite (NC) based on Fe3O4/ZnO, to eliminate four persistent antibiotics in surface waters: sulfamethoxazole, trimethoprim, erythromycin and roxithromycin. Prior to the operation of the photocatalytic reactor, the influence of pH (3-9), catalyst concentration (50-800 mg L-1), oxidant dose (0-100 mg L-1) and concentration of different targets (10-100 µg L-1) on the catalytic efficiency was evaluated. The analysis of reaction kinetics showed that degradation processes of the four antibiotics followed a pseudo-first-order kinetic model. Antibiotics adsorption onto the nanocomposite surface depended on their electrostatic nature and played an important role when decreasing the initial concentration of antibiotics. In this context, kinetic rates were higher at lower initial levels of organic pollutants, which is a favourable effect from a practical application perspective. On the other hand, a synergistic effect of the available Fe in the nanocomposite was found, contributing to the oxidation of antibiotics by photo-Fenton as a secondary reaction. Then, a magnetic photocatalytic reactor was operated under optimal conditions. The enhanced photonic efficiency of Fe3O4/ZnO in the system, as well as the ease of the magnetic separation and catalyst reusability, indicate the viability of this reactor configuration.

Risk factors and clinical impact of multidrug resistance in healthcare-associated bacteraemic urinary tract infections: a post-hoc analysis of a multicentre prospective cohort in Spain.

BACKGROUND: The global burden associated with antimicrobial resistance is of increasing concern. AIM: To evaluate risk factors associated with multidrug-resistant (MDR) infection and its clinical impact in a cohort of patients with healthcare-associated bacteraemic urinary tract infections (BUTIs). METHODS: This was a prospective, multicentre, post-hoc analysis of patients with healthcare-associated-BUTI (ITUBRAS-2). The primary outcome was MDR profile. Secondary outcomes were clinical response (at 48-72 h and at hospital discharge) and length of hospital stay from onset of BUTI. Logistic regression was used to evaluate variables associated with MDR profile and clinical response. Length of hospital stay was evaluated using multivariate median regression. FINDINGS: In all, 443 episodes were included, of which 271 (61.17%) were classified as expressing an MDR profile. In univariate analysis, MDR profile was associated with E. coli episodes (odds ratio (OR): 3.13; 95% confidence interval (CI): 2.11-4.69, P < 0.001) and the extensively drug-resistant (XDR) pattern with P. aeruginosa aetiology (7.84; 2.37-25.95; P = 0.001). MDR was independently associated with prior use of fluoroquinolones (adjusted OR: 2.43; 95% CI: 1.25-4.69), cephalosporins (2.14; 1.35-3.41), and imipenem or meropenem (2.08; 1.03-4.20) but not with prior ertapenem. In terms of outcomes, MDR profile was not associated with lower frequency of clinical cure, but was associated with longer hospital stay. CONCLUSION: MDR profile was independently associated with prior use of fluoroquinolones, cephalosporins, imipenem, and meropenem, but not with prior ertapenem. MDR-BUTI episodes were not associated with worse clinical cure, although they were independently associated with longer duration of hospital stay.

Iron oxide-mediated photo-Fenton catalysis in the inactivation of enteric bacteria present in wastewater effluents at neutral pH.

The pressure on natural water resources associated with increasing water scarcity highlights the value of using reclaimed water through the development of efficient and environmentally friendly treatment technologies. In this work, the use of magnetic nanoparticles in photo-Fenton catalysis for water disinfection was considered to inactivate natural enteric bacteria present in municipal wastewater effluents under white light and neutral pH. The most recommended ranges were evaluated in key variables such as the loading and composition of nanoparticles (NPs), hydrogen peroxide (H2O2) concentration, the light source (UV and visible) and treatment time were evaluated in wastewater disinfection expressed in terms of total coliforms and Escherichia coli colony forming units (CFU). The magnetic separation of NPs allowed the disinfection process to be carried out in different cycles, facilitating the recovery of the nanocatalyst and avoiding its discharge with the treated effluent.