Antimicrobial activity of nanoconjugated glycopeptide antibiotics and their effect on Staphylococcus Aureus biofilm

In the era of antimicrobial resistance, the use of nanoconjugated antibiotics is regarded as a promising approach for preventing and fighting infections caused by resistant bacteria, including those exacerbated by the formation of difficult-to-treat bacterial biofilms. Thanks to their biocompatibility and magnetic properties, iron oxide nanoparticles (IONPs) are particularly attractive as antibiotic carriers for the targeting therapy. IONPs can direct conjugated antibiotics to infection sites by the use of an external magnet, facilitating tissue penetration and disturbing biofilm formation. As a consequence of antibiotic localization, a decrease in its administration dosage might be possible, reducing the side effects to non-targeted organs and the risk of antibiotic resistance spread in the commensal microbiota. Here, we prepared nanoformulations of the ‘last-resort’ glycopeptides teicoplanin and vancomycin by conjugating them to IONPs via surface functionalization with (3-aminopropyl) triethoxysilane (APTES). These superparamagnetic NP-TEICO and NP-VANCO were chemically stable and NP-TEICO (better than NP-VANCO) conserved the typical spectrum of antimicrobial activity of glycopeptide antibiotics, being effective against a panel of staphylococci and enterococci, including clinical isolates and resistant strains. By a combination of different methodological approaches, we proved that NP-TEICO and, although to a lesser extent, NP-VANCO were effective in reducing biofilm formation by three methicillin-sensitive or resistant Staphylococcus aureus strains. Moreover, when attracted and concentrated by the action of an external magnet, NP-TEICO exerted a localized inhibitory effect on S. aureus biofilm formation at low antibiotic concentration. Finally, we proved that the conjugation of glycopeptide antibiotics to IONPs reduced their intrinsic cytotoxicity toward a human cell line. Copyright © 2021 Berini, Orlandi, Gamberoni, Martegani, Armenia, Gornati, Bernardini and Marinelli

Vertical Specialization, Tariff Shirking and Trade

The core idea behind the paper is that trade policy matters for the organization of global value chains, a notion largely neglected by economists but which has important implications for our understanding of trade and the international transmission of trade policy shocks. We develop a theoretical model in which a firm's ability to spatially separate manufacturing from headquarter services gives them the flexibility to circumvent economy-specific tariff changes by switching their assembly location abroad. We show that tariff shirking increases the elasticity of bilateral trade to economy-specific tariff hikes due to an extra extensive margin effect. Furthermore, we show that tariff shirking affects the vulnerability of headquarter services and manufacturing to trade policy shocks in opposite ways. While tariff shirking dampens the vulnerability of headquarter services to trade policy shocks, it amplifies the vulnerability of manufacturing to trade policy shocks. Using firm-level and province-level export data from the People's Republic of China, we provide evidence in line with the theoretical model

Geografia dell'acqua. La gestione di una risorsa fondamentale per la costruzione del territorio

il tema acqua oggetto di studio e riflessioni della geografia. Convegno Scientifico Internazionale "Geografie dell'acqua. La gestione di una risorsa fondamentale per la costruzione del territorio

Geografia (5^)

autori: G. PONTARA, E. GAMBERONI, S. LAMBERTI e B. PERIN Serie: Quaderni Fabbri 2000 Volume di schede operative per alunni della scuola primaria classe quint

Ma la geografia \ue8 un sapere irrinunciabile?

ruolo della geografia alla luce del documento ministeriale sui saperi irrinunciabil

Geografia IV

Autori: E. Gamberoni, N. Girelli e S. Lamberti. testo operativo per la scuola primari

Geografia e Ricerca Visuale

recensione al volume di E. Bignant