Medical device-associated infections are a major health threat, representing about half of all hospital-acquired infections. Current strategies to prevent this problem based on device coatings with antimicrobial compounds (antibiotics or antiseptics) have proven to be insufficient, often toxic, and even promoting bacterial resistance. Herein, we report the development of an infection-preventive coating (CyanoCoating) produced with an extracellular polymer released by the marine cyanobacterium Cyanothece sp. CCY 0110. CyanoCoating was prepared by spin-coating and its bacterial anti-adhesive efficiency was evaluated against relevant etiological agents (Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa and Escherichia coli) and platelets, both in the presence or absence of human plasma proteins. CyanoCoating cytotoxicity was assessed using the L929 fibroblasts cell line. CyanoCoating exhibited a smooth topography, low thickness and high hydrophilic properties with mild negative charge. The non-cytotoxic CyanoCoating prevented adhesion of all the bacteria tested (≤80%) and platelets (<87%), without inducing platelet activation (even in the presence of plasma proteins). The significant reduction in protein adsorption (<77%) confirmed its anti-adhesive properties. The development of this anti-adhesive coating is an important step towards the establishment of a new technological platform capable of preventing medical device-associated infections, without inducing thrombus formation in blood-contacting applications.

Prevention of orthopedic implant-related infections is a major medical challenge, particularly due to the involvement of biofilm-encased and multidrug-resistant bacteria. Current therapies, based on antibiotic administration, have proven to be insufficient, and infection prevalence may rise due to the dissemination of antibiotic resistance. Antimicrobial peptides (AMPs) have attracted attention as promising substitutes of conventional antibiotics, owing to their broad-spectrum of activity, high efficacy at very low concentrations, and, importantly, low propensity for inducing resistance. The aim of this review is to offer an updated perspective of the development of AMPs-based preventive strategies for orthopedic and dental implant-related infections. In this regard, two major research strategies are herein addressed, namely (i) AMP-releasing systems from titanium-modified surfaces and from bone cements or beads; and (ii) AMP immobilization strategies used to graft AMPs onto titanium or other model surfaces with potential translation as coatings. In overview, releasing strategies have evolved to guarantee higher loadings, prolonged and targeted delivery periods upon infection. In addition, avant-garde self-assembling strategies or polymer brushes allowed higher immobilized peptide surface densities, overcoming bioavailability issues. Future research efforts should focus on the regulatory demands for pre-clinical and clinical validation towards clinical translation.

Catheter-associated urinary tract infections (CAUTIs) represent about 40% of all healthcare-associated infections. Herein, the authors report the further development of an infection preventive anti-adhesive coating (CyanoCoating) meant for urinary catheters, and based on a natural polymer released by a marine cyanobacterium. CyanoCoating performance was assessed against relevant CAUTI etiological agents, namely Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, methicillin resistant Staphylococcus aureus (MRSA), and Candida albicans in the presence of culture medium or artificial urine, and under biofilm promoting settings. CyanoCoating displayed a broad anti-adhesive efficiency against all the uropathogens tested (68–95%), even in the presence of artificial urine (58–100%) with exception of P. mirabilis in the latter condition. Under biofilm-promoting settings, CyanoCoating reduced biofilm formation by E. coli, P. mirabilis, and C. albicans (30–60%). In addition, CyanoCoating prevented large crystals encrustation, and its sterilization with ethylene oxide did not impact the coating stability. Therefore, CyanoCoating constitutes a step forward for the implementation of antibiotic-free alternative strategies to fight CAUTIs.

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Host defense peptides (HDPs) comprise a heterogeneous group of evolutionarily conserved and biologically active small molecules that are produced by different organisms. HDPs are widely researched because they often have multiple biological activities, for example antimicrobial, immunomodulatory and anticancer activity. In this context, in this review we focus on cryptic HDPs, molecules derived specifically from proteolytic processing of endogenous precursor proteins. Here, we explore the biological activity of such molecules and we further discuss the development of optimized sequences based on these natural cryptic HDPs. In addition, we present clinical-phase studies of cryptic HDPs (natural or optimized), and point out the possible applicability of these molecules in medicinal chemistry.

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Stents and urinary catheters are commonly used medical devices, whose need is forecasted to grow considering not only the world population increase but also its aging and sedentary lifestyle.Independently of the great development on biomaterials and device design, infection represents still a major cause of failure of these devices, with undeniable humane and economical costs. Different antibiotic-based solutions have appeared in the market to try to address the matter. However, there is growing evidence on the impact of antibiotic-resistant microorganisms on urinary tract medical-devices infections, and respective outcomes. A broad number of alternatives have been proposed, however, given the wide variability of results for different strategies, there remains a tremendous need to validate their clinical significance, particularly assuring patient safety. Additionally, most of these strategies might be advantageous while in combination with current therapies, so further studies are needed.