Co-immobilization of Palm and DNase I for the development of an effective anti-infective coating for catheter surfaces

Biomaterial-associated infections, in particular, catheter-associated infections (CAI) are a major problem in clinical practice due to their ability to resist antimicrobial treatment and the host immune system. This study aimed to co-immobilize the antimicrobial lipopeptide Palm and the enzyme DNase I to introduce both antimicrobial and anti-adhesive functionalities to polydimethylsiloxane (PDMS) material, using dopamine chemistry. Surface characterization confirmed the immobilization of both compounds and no leaching of Palm from the surfaces for up to 5 days. Co-immobilization of both agents resulted in a bifunctional coating with excellent surface antimicrobial and anti-biofilm properties against both Staphylococcus aureus and Pseudomonas aeruginosa. The modified surfaces demonstrated superior biocompatibility. To better discriminate co-adhesion of both species on modified surfaces, PNA FISH (Fluorescence in situ hybridization using peptide nucleic acid probes) was employed, and results showed that P. aeruginosa was the dominant organism, with S. aureus adhering afterwards on P. aeruginosa agglomerates. Furthermore, Palm immobilization exhibited no propensity to develop bacterial resistance, as opposite to the immobilization of an antibiotic. The overall results highlighted that co-immobilization of Palm and DNase I holds great potential to be applied in the development of catheters.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI- 01-0145-FEDER-006684). The authors also acknowledge the support by FCT and the European Community fund FEDER, through Program COMPETE, under the scope of the Projects AntiPep PTDC/SAU-SAP/113196/2009 (FCOMP-01-0124-FEDER-016012) and RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the PhD Grant of Diana Alves (SFRH/BD/78063/2011). This study was also supported by the statutory fund from the Medical University of Gdansk (Project No. 02-0087/07/508)

Anti-biofilm peptide combinations against Pseudomonas aeruginosa and Staphylococcus aureus

Today, we are facing a major challenge regarding the development of new strategies and the discovery of new compounds with effective antimicrobial outcomes. The emergence of resistance is a preoccupant health threat and conventional antibiotics are being rendered ineffective [1]. Specifically, biofilm related infections are becoming a serious threat, being highly related to chronic infections but also nosocomial and biomaterial related infections, and they are considered the major cause of dissemination of antibiotic resistance in the nosocomial scenario. Researchers are now focusing in alternatives, such as the discovery of new antimicrobials with different modes of action, and the combination of agents potentiating their efficacy. AMPs are an example of new antimicrobials with promising applications, since they have different and sometimes unspecific mechanisms of action compared to traditional antibiotics, reducing the chance of acquired resistance, and are showing promising results in the biofilm area. A growing interest has been emerging for the use of antimicrobial combinations as a strategy to increase the antimicrobial spectrum, prevent the emergence of resistance, reduce toxicity and side effects and provide synergistic activity. Because of this, in this work we analyse AMP combinations against major pathogenic bacteria, Pseudomonas aeruginosa and Staphylococcus aureus, currently great contributors for resistance development and responsible for chronic infections, such as cystic fibrosis pneumonia. We present a screening of combinations of the AMP antibiotic colistin with the AMPs temporin A, citropin 1.1 and tachyplesin I against these pathogens, including references and clinical isolated strains. Planktonic and biofilm mode of growth were implemented and results show that most combinations have addictive and synergetic activities, including total inhibition of biofilm formation for some of the combinations tested. This means that AMP combinations should be a viable way for the development of new antimicrobial treatments, thus reducing their toxicity and side effects, while maintaining efficacy

Searching for new strategies against biofilm infections: Colistin-AMP combinations against Pseudomonas aeruginosa and Staphylococcus aureus single- and double-species biofilms

Antimicrobial research is being pressured to look for more effective therapeutics for the ever-growing antibiotic-resistant infections, and antimicrobial peptides (AMP) and antimicrobial combinations are promising solutions. This work evaluates colistin-AMP combinations against two major pathogens, Pseudomonas aeruginosa and Staphylococcus aureus, encompassing non- and resistant strains. Colistin (CST) combined with the AMP temporin A (TEMP-A), citropin 1.1 (CIT-1.1) and tachyplesin I linear analogue (TP-I-L) was tested against planktonic, single- and double-species biofilm cultures. Overall synergy for planktonic P. aeruginosa and synergy/additiveness for planktonic S. aureus were observed. Biofilm growth prevention was achieved with synergy and additiveness. Pre-established 24 h-old biofilms were harder to eradicate, especially for S. aureus and double-species biofilms; still, some synergy and addictiveness was observed for higher concentrations, including for the biofilms of resistant strains. Different treatment times and growth media did not greatly influence AMP activity. CST revealed low toxicity compared with the other AMP but its combinations were toxic for high concentrations. Overall, combinations reduced effective AMP concentrations, mainly in prevention scenarios. Improvement of effectiveness and toxicity of therapeutic strategies will be further investigated.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT) (http://www.fct.pt/), under the scope of the strategic funding of UID/B10/04469/2013 and COMPETE 2020 (POCI-01-0145-FEDER-006684). This study was also supported by FCT and the European Community fund FEDER, through Program COMPETE, and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 -Programa Operacional Regional do Norte. This work was also partially funded by the [14V105] Contract-Programme from the University of Vigo (https://mw.uvigo.gal/ uvigo_en/) and the Agrupamento INBIOMED (http://inbiomed.webs.uvigaes/) from DXPCTSUG-FEDER unha maneira de facer Europa (2012/273) and co-financed by the European Regional Development Fund (http://ec.europleuiregionaL policy/EN/fundingierdf/) under the Operational Programme Innovative Economy (WNP-POIG.01.04.00-22-052/11).). Lipopharm.pl (http://www.lipopharm.p1/) provided support in the form of salaries for authors DG and WK. The authors also acknowledge the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) (https://www.escmid.org/) for the Research Grant 2014 to Anglia Lourenco, and FCT for the PhD Grant of Paula Jorge (grant number SFRH/BD/88192/2012). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.info:eu-repo/semantics/publishedVersio

Novel glycosylated endomorphin-2 analog produces potent centrally-mediated antinociception in mice after peripheral administration

We report the synthesis and pharmacological characterization of a novel glycosylated analog of a potent and selective endogenous mu-opioid receptor (MOP) agonist, endomorphin-2 (Tyr-Pro-Phe-Phe-NH2, EM2), obtained by the introduction in position 3 of the tyrosine residue possessing the glucose moiety attached to the phenolic function via a beta-glycosidic bond. The improved blood-brain barrier permeability and enhanced antinociceptive effect of the novel glycosylated analog suggest that it may be a promising template for design of potent analgesics. Furthermore, the described methodology may be useful for increasing the bioavailability and delivery of opioid peptides to the CNS. (C) 2013 Elsevier Ltd. All rights reserved

Treatment media and treatment time influence on single AMP activity on 24 h-old <i>P</i>. <i>aeruginosa</i> biofilms.

<p>Concentrations used were 32 mg L^-1 of CST and 64 mg L^-1 of the other AMP. A) <i>P</i>. <i>aeruginosa</i> PAO1, B) <i>P</i>. <i>aeruginosa</i> CI and C) <i>P</i>. <i>aeruginosa</i> CI MDR.</p