Synergic combinations of antimicrobial peptides (AMPs) against biofilms of methicillin-resistant Staphylococcus aureus (MRSA) on polystyrene and medical devices.

Abstract Objectives Antimicrobial research is being focused to look for more effective therapeutics against antibiotic-resistant infections caused by methicillin-resistantStaphylococcus aureus (MRSA). In this direction, antimicrobial peptides (AMP) appears a promising solution. The aim of the present study was to investigate the potential activity of Temporin A, Citropin 1.1, CA(1–7)M(2–9)NH2 and Pal-KGK-NH2 in synergic activity against MRSA biofilms developed on polystyrene surface (PSS) and central venous catheter (CVC). Methods The research was subdivided into distinct phases to assess the ability of AMPs to inhibit biofilm formation, to identify a possible synergy between AMPs, and to eradicate preformed biofilms on PSS and CVC using AMPs alone or in combination. Results The activity of the AMPs was particularly evident in the inhibition of biofilm formation on PSS and on CVC, while the eradication of preformed biofilms was more difficult and was reached only after 24 h of contact. The synergic activity of AMPs combinations, selected by their FICI, has led to an improvement in the performance of all the molecules in the removal of different biofilms. Conclusions Overall, AMPs could represent the next generation of antimicrobial agents for a prophylactic or therapeutic tool to control biofilm of antibiotic-resistant and/or biofilm-associated infections on different medical devices

Valutazione in vitro dell'azione antimicrobica e anti-biofilm di AMPs nei confronti di Staphylococcus aureus meticillino-resistenti (MRSA).

Il largo impiego di medical devices in pratica clinica ha reso necessaria la ricerca di mezzi sempre più potenti nel prevenire la formazione di biofilm, nei quali i patogeni sono protetti da una matrice di materiale polisaccaridico, resistente alla maggior parte di terapie antibiotiche. L’adesione dei batteri alle superfici, facilitata da diversi fattori come elevate forze idrodinamiche, la motilità batterica e le interazioni elettrostatiche tra i microorganismi e le superfici, rappresenta la prima fondamentale fase nello sviluppo del biofilm. Impedire l’instaurarsi di questo primo step potrebbe potenzialmente prevenire o ridurre la formazione del biofilm sui dispostivi medici, riducendo quindi il rischio di infezioni a questi associate. Inoltre il progressivo e preoccupante fenomeno delle resistenze agli antibiotici rappresenta un serio problema per la salute collettiva rendendo sempre più urgente il bisogno di far fronte a tale emergenza. La soluzione più plausibile, oltre ad un utilizzo più prudente e razionale delle molecole attualmente in uso, sembra quella di individuare nuove molecole con attività antimicrobica da poter utilizzare un giorno in pratica clinica. Dall’attuale stato dell’arte sui peptidi ad azione antimicrobica si evince che queste molecole ad oggi sono tra le più promettenti. Alla luce di quanto detto lo scopo di questa tesi è quello di valutare l’efficacia antimicrobica di alcuni AMPs, senza l’ausilio dei comuni antibiotici utilizzati in clinica, su isolati clinici di S. aureus meticillino-resistenti (MRSA). Il progetto è stato suddiviso in tre fasi per valutare i) l’attività antimicrobica degli AMPs mediate determinazione delle MIC/MBC e killing studies; ii) le loro capacità anti-biofilm e iii) delinearne l’eventuale efficacia nella rimozione di biofilm preformati sia su polistirene che su medical devices da soli e/o in combinazione. I nostri dati hanno verificato l’attività antimicrobica degli AMPs nei confronti della forma planctonica di S. aureus MRSA, mediante determinazione delle MIC e dei killing studies; contemporaneamente, è stata evidenziata come la concentrazione usata nella fase planctonica non era sufficiente nei confronti degli stessi batteri organizzati in biofilm, sui quali è stato necessario impiegare concentrazioni superiori. L’attività anti-biofilm dei diversi AMPs è stata decisamente più marcata nell’inibizione della formazione del biofilm su polistirene e su medical devices, mentre l’eradicazione dei biofilm preformati sulle stesse superfici è risultata più difficoltosa. I dati ottenuti, anche se preliminari, hanno infine dimostrato che gli AMPs sono in grado, dopo 24h di contatto, di rimuovere i biofilm formati su polistirene e su cateteri venosi

Live and heat-killed Lactobacillus spp. interfere with Streptococcus mutans and Streptococcus oralis during biofilm development on titanium surface

This research investigates the ability of live and heat-killed (HK) Lactic Acid Bacteria (LAB) to interfere with Streptococcus mutans ATCC 25175 and Streptococcus oralis ATCC 9811 during biofilm formation

Archivi e contaminazioni disciplinari: dai linguaggi ai modelli, dai metodi alle tecniche

The article illustrates the disciplinary contamination - in terms of approaches, methods and techniques - of the project Portale per le fonti della storia della Repubblica italiana, in which the CNR participates through the institutes ILIESI, IMATI, ISTC. Starting from a reflection on the polysemic notion of “archive” (as a repository, a place of access and a resource-entry), the contribution reflects on how to make research applied to historical archives inclusive, stimulating the interest of different audiences. Designing a transversal system means reflecting on how different disciplines communicate and represent concepts: it means thinking about effective communication codes between disciplinary domains (different domains, however similar or complementary). Moreover, in order not to create a communication aimed only at domain experts and professionals, it is necessary to use a non-technical language to make the conceptualisation explicit and comprehensible to a wide public

Chitosans inhibit the growth and the adhesion of Klebsiella pneumoniae and Escherichia coli clinical isolates on urinary catheters

Objective The aim of this study was to determine the antimicrobial activity of different chitosans (CS) against typical colonizing pathogens of the urinary tract and to assess their efficacy against bacterial adhesion and the subsequent biofilm formation on urinary catheters. Methods The antimicrobial activity of high and low molecular weight CS (50 and 150 kDa) at pH 5.0 and 6.0 was tested against Klebsiella pneumoniae and Escherichia coli clinical isolates by time–kill studies. The anti-adhesion assays on Foley urinary catheters were performed in Artificial Urine Medium (AUM) with the addition of each CS (AUM-CS) at the same pH values. Finally, the efficacy over time of chitosan treatments on bacterial adhesion on urinary catheters was determined. Results A viability reduction of K. pneumoniae and E. coli isolates, regardless of pH value, was evidenced in time–kill studies, in particular in the presence of CS 50 kDa. As regards the anti-adhesion efficacy on urinary catheters, high and low molecular weight CS evidenced a higher efficacy to reduce bacterial adhesion at pH 5.0. A low number of viable K. pneumoniae and E. coli cells were recovered from catheters after CS treatments, highlighting a promising efficacy over time. Conclusion Our data show the potential of chitosans to reduce or prevent not only the adhesion of well-known human uropathogens on urinary catheters but also the re-growth ability of the uropathogens

Increased Levels of Erythropoietin in Nipple Aspirate Fluid and in Ductal Cells from Breast Cancer Patients

Background: Erythropoietin (Epo) is an important regulator of erythropoiesis, and controls proliferation and differentiation of both erythroid and non-erythroid tissues. Epo is actively synthesized by breast cells during lactation, and also plays a role in breast tissues promoting hypoxia-induced cancer initiation. Our aims are to perform an exploratory investigation on the Epo accumulation in breast secretions from healthy and cancer patients and its localization in breast cancer cells

Identification and functional traits of lactic acid bacteria isolated from Ciauscolo salami produced in Central Italy

Lactic acid bacteria (LAB) from Ciauscolo salami produced in Marche Region of Central Italy, and LAB strains be-longing to our laboratory collection were examined for their capability to survive at low pH and bile, to adhere to Caco-2cells, and for antibiotic resistance. LAB fromCiauscolo were identifiedbyARDRAandRAPD-PCR. Our study showed that all LAB strains hadgood adaptation to gastric juice andmoderate tolerance to bile. The adhesiveness was variable among strains but significantly lower in LAB from food. Antibiotic resistance was broadly spread among food strains, with level of resistance exceeding 15% for all the antibiotics tested. The resistance determi-nantserm(B) andtet(M) were found in nine strains of food origin (21.4%)whiletet(L) in one strain of our collec-tion (5%). Our work suggests that fermented foods are valuable sources of bacterial strains with functional traits of intestinal lactobacilli. These bacteria may be further studied for their use in probiotic applications

In vitro activity of Carvacrol against titanium-adherent oral biofilms and planktonic cultures

The aim of this study was to test the effect of Carvacrol against oral pathogens and their preformed biofilms on titanium disc surface. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and biofilm inhibitory concentration (BIC) were performed to evaluate Carvacrol antibacterial activity, while flow cytometry (FCM) was used to verify the Carvacrol effect on esterase activity and mem-brane permeability. Carvacrol was tested in vitro on single-and multi-species biofilms formed on titanium disc by Streptococcus mutans ATCC 25175, Porphyromonas gingivalis ATCC 33277 or Fusobacterium nucleatum ATCC 25586, in different combinations, comparing its effect to that of chlorhexidine. Results: The pathogens were sensitive to Carvacrol with MICs and MBCs values of 0.25 % and 0.50 % and BICs of 0.5% for S. mutans ATCC25175 and 1% for P. gingivalis ATCC 33277 and F. nucleatum ATCC 25586. FCM analysis showed that treatment of planktonic cultures with Carvacrol caused an increase of damaged cells and a decrement of bacteria with active esterase activity. Moreover, Carvacrol demonstrated greater biofilm formation preventive proper-ty compared to chlorhexidine against titanium-adherent single- and multi-specie biofilms, with statistically signifi-cant values. Conclusions:Carvacrol showed inhibitory activity against the tested oral pathogens and biofilm formation preven-tive property on their oral biofilm; then, it could be utilized to control and prevent the colonization of microorganisms with particular significance in human oral diseases. Clinical relevance: This natural compound may be proposed in daily hygiene formulations or as an alternative agent supporting traditional antimicrobial protocols to prevent periodontal diseases in implanted patients