Search

Pathogens such as Staphylococcus aureus are able to survive in many types of host cells including phagocytes such as neutrophils and macrophages, thereby resulting in intracellular infections. Treatment of intracellular infections by conventional antimicrobials (e.g., antibiotics) is often ineffective due to low intracellular efficacy of the drugs. Thus, novel techniques which can enhance the activity of antimicrobials within cells are highly demanded. Our recent studies have shown that photochemical internalization (PCI) is a promising approach for improving the efficacy of antibiotics such as gentamicin against intracellular staphylococcal infection. In this chapter, we describe the protocols aiming to study the potential of PCI-antibiotic treatment for intracellular infections in vitro and in vivo using a RAW 264.7 cell infection model and a zebrafish embryo infection model. Proof of concept of this approach is demonstrated. The protocols are expected to prompt further development of PCI-antimicrobial based novel therapies for clinically challenging infectious diseases associated with intracellular survival of pathogens., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

Bacterial adhesion and subsequent biofilm formation on biomedical implants and devices are a major cause of their failure. As systemic antibiotic treatment is often ineffective, there is an urgent need for antimicrobial biomaterials and coatings. The term "antimicrobial" can encompass different mechanisms of action (here termed "antimicrobial surface designs"), such as antimicrobial-releasing, contact-killing or non-adhesivity. Biomaterials equipped with antimicrobial surface designs based on different mechanisms of action require different in vitro evaluation methods. Available industrial standard evaluation tests do not address the specific mechanisms of different antimicrobial surface designs and have therefore been modified over the past years, adding to the myriad of methods available in the literature to evaluate antimicrobial surface designs. The aim of this review is to categorize fourteen presently available methods including industrial standard tests for the in vitro evaluation of antimicrobial surface designs according to their suitability with respect to their antimicrobial mechanism of action. There is no single method or industrial test that allows to distinguish antimicrobial designs according to all three mechanisms identified here. However, critical consideration of each method clearly relates the different methods to a specific mechanism of antimicrobial action. It is anticipated that use of the provided table with the fourteen methods will avoid the use of wrong methods for evaluating new antimicrobial designs and therewith facilitate translation of novel antimicrobial biomaterials and coatings to clinical use. The need for more and better updated industrial standard tests is emphasized., Statement of Significance: European COST-action TD1305, IPROMEDAI aims to provide better understanding of mechanisms of antimicrobial surface designs of biomaterial implants and devices. Current industrial evaluation standard tests do not sufficiently account for different, advanced antimicrobial surface designs, yet are urgently needed to obtain convincing in vitro data for approval of animal experiments and clinical trials. This review aims to provide an innovative and clear guide to choose appropriate evaluation methods for three distinctly different mechanisms of antimicrobial design: (1) antimicrobial-releasing, (2) contact-killing and (3) non-adhesivity. Use of antimicrobial evaluation methods and definition of industrial standard tests, tailored toward the antimicrobial mechanism of the design, as identified here, fulfill a missing link in the translation of novel antimicrobial surface designs to clinical use., (Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

The aim of this study was to cover the surfaces of zirconium (Zr) with an antimicrobial layer for biomedical applications. For this purpose, the micro-arc oxidation (MAO) process was employed in a sodium silicate and sodium hydroxide containing base electrolyte with and without addition of silver acetate (AgC 2 H 3 O 2 ). In general, synthesized MAO layers were composed of zirconium oxide (ZrO 2 ) and zircon (ZrSiO 4 ). Addition of AgC 2 H 3 O 2 into the base electrolyte caused homogenous precipitation of silver-containing particles in the MAO layer, which exhibited excellent antibacterial efficiency against methicillin-resistant Staphylococcus aureus (MRSA) as compared to the untreated and MAO-treated Zr., (Copyright © 2016 Elsevier B.V. All rights reserved.)