Therapeutic Options for Infections due to vanB Genotype Vancomycin-Resistant Enterococci.

Enterococci are ubiquitous, facultative, anaerobic Gram-positive bacteria that mainly reside, as part of the normal microbiota, in the gastrointestinal tracts of several animal species, including humans. These bacteria have the capability to turn from a normal gut commensal organism to an invasive pathogen in patients debilitated by prolonged hospitalization, concurrent illnesses, and/or exposed to broad-spectrum antibiotics. The majority of vancomycin-resistant enterococcus (VRE) infections are linked to the vanA genotype; however, outbreaks caused by vanB-type VREs have been increasingly reported, representing a new challenge for effective antimicrobial treatment. Teicoplanin, daptomycin, fosfomycin, and linezolid are useful antimicrobials for infections due to vanB enterococci. In addition, new drugs have been developed (e.g., dalbavancin, telavancin, and tedizolid), new molecules will soon be available (e.g., eravacycline, omadacycline, and oritavancin), and new treatment strategies are progressively being used in clinical practice (e.g., combination therapies and bacteriophages). The aim of this article is to discuss the pathogenesis of infections due to enterococci harboring the vanB operon (vanBVRE) and their therapeutic, state-of-the-art, and future treatment options and provide a comprehensive and easy to use review for clinical purposes.

Metabolic profiling of a polyphenolic-rich fraction of Coccinia grandis leaves using LC-ESI-MS/MS and in vivo validation of its antimicrobial and wound healing activities.

A polyphenolic-rich fraction (CG50) was obtained from the methanol extract of Coccinia grandis leaves by chromatographic fractionation over a Diaion column using 50% aqueous methanol. LC-ESI-MS/MS analysis of CG50 showed the presence of six flavonoids, namely quercetin-hexoside deoxyhexoside (rutin), quercetin-hexoside deoxyhexoside (quercetin-3-O-neohesperidoside), kaempferol-hexoside deoxyhexoside (kaempferol-3-O-rutinoside), kaempferol-hexoside deoxyhexoside (kaempferol-3-O-neohesperidoside), kaempferol-3-O-glucoside, and kaempferol-hexoside in addition to the presence of two secoiridoids which are oleuropein and ligstroside. CG50 hydrogel showed a pronounced inhibition of the bacterial growth in wounds infected by Bacillus cereus in rats comparable to those treated with hydrogel base only showing 85.08 and 16.50% inhibition for the bacterial growth for the CG50 hydrogel and hydrogel base, respectively. The antimicrobial activity of CG50 hydrogel was close to that of fucidin during all days of treatment. Rats treated with CG50 hydrogel showed remarkable healing ability of the wound compared to other groups and approaching that of fucidin. This was clearly manifested by the clear formation of scars with obvious reduction in the wound size together with the appearance and re-growth of hair. This was further confirmed by the histopathological study of skin tissues as well as by the evaluation of the percentages of collagen fiber deposition. CG50 hydrogel showed 18.71% collagen fiber deposition comparable to the untreated group that showed 6.84% collagen fiber deposition and approaches that of the fucidin group. It was concluded that Coccinia grandis could be used as a natural wound healing agent that further consolidated its traditional use as a wound dressing.

Antibacterial Properties Associated with Chitosan Nanoparticle Treatment on Root Dentin and 2 Types of Endodontic Sealers.

INTRODUCTION: The aim of this study was to evaluate the efficacy of carboxymethyl chitosan (CMCS) and chitosan nanoparticles (CNps) to inactivate bacteria and prevent biofilm formation at sealer-dentin interfaces. METHODS: The study was divided into 3 stages: first stage, the experiment was conducted to analyze the antibacterial properties of CMCS in different formulations against biofilms; second stage, direct-contact and membrane-restricted methods were used to evaluate the antibacterial properties of an epoxy resin (ThermaSeal Plus; Dentsply Tulsa Dental, Tulsa, OK) and calcium silicate (MTA Fillapex; Angelus SA, Londrina, PR, Brazil) based-sealers with or without CNps; and third stage, biofilm formation at the sealer dentin interfaces of root dentin treated with CMCS and filled with gutta-percha and CNp incorporated sealer were analyzed after 1- and 4-week aging periods. The samples were treated and filled as follows: (1) distilled water: unaltered sealer (control group), (2) CMCS: sealer+CNps (CMCS group), and (3) CMCS/rose bengal: sealer+CNps (CMCS/RB group). Enterococcus faecalis was used to infect all the samples. Microbiological and microscopic analyses were used to assess the antibacterial characteristics. RESULTS: CMCS-based treatments effectively killed bacteria adherent on root dentin (P < .05). The addition of CNps to ThermaSeal enhanced its antibacterial ability by direct-contact and membrane-restricted tests (P < .05). The CNp incorporation significantly increased the antibacterial efficacy of root canal sealers even after a 4-week aging time (P < .05). CONCLUSIONS: This study highlighted the ability of CMCS to disinfect root canal dentin and inhibit bacterial adhesion. CNps in root canal sealers are capable of maintaining their antibacterial activity even after prolonged aging.

Treatment and prevention of enterococcal infections--alternative and experimental approaches.

Enterococci are one of the leading types of organisms isolated from infections of hospitalised patients and the third most common cause of nosocomial bloodstream infections. They contribute significantly to patient mortality and morbidity, as well as healthcare costs. The emergence of resistance against virtually all clinically available antibiotics and the ability to transfer these resistance determinants to other pathogens demonstrates the urgency for an improved understanding of enterococcal virulence mechanisms, and the development of alternative treatment and prevention options. This article reviews new antimicrobials, vaccine targets, bacteriophage therapy, as well as treatments targeting virulence factors and biofilm, for their potential to treat and/or prevent enterococcal infections. Although clinical isolates often cause serious infections, so-called 'non-pathogenic' strains are used as therapeutics in the form of probiotics. Understanding the differences between true pathogens and beneficial commensals may help to evaluate future treatment and prophylactic options.