Adipokinetic hormones and their G protein-coupled receptors emerged in Lophotrochozoa

Most multicellular animals belong to two evolutionary lineages, the Proto– and Deuterostomia, which diverged 640–760 million years (MYR) ago. Neuropeptide signaling is abundant in animals belonging to both lineages, but it is often unclear whether there exist evolutionary relationships between the neuropeptide systems used by proto- or deuterostomes. An exception, however, are members of the gonadotropin-releasing hormone (GnRH) receptor superfamily, which occur in both evolutionary lineages, where GnRHs are the ligands in Deuterostomia and GnRH-like peptides, adipokinetic hormone (AKH), corazonin, and AKH/corazonin-related peptide (ACP) are the ligands in Protostomia. AKH is a well-studied insect neuropeptide that mobilizes lipids and carbohydrates from the insect fat body during flight. In our present paper, we show that AKH is not only widespread in insects, but also in other Ecdysozoa and in Lophotrochozoa. Furthermore, we have cloned and deorphanized two G protein-coupled receptors (GPCRs) from the oyster Crassostrea gigas (Mollusca) that are activated by low nanomolar concentrations of oyster AKH (pQVSFSTNWGSamide). Our discovery of functional AKH receptors in molluscs is especially significant, because it traces the emergence of AKH signaling back to about 550 MYR ago and brings us closer to a more complete understanding of the evolutionary origins of the GnRH receptor superfamily

Success Rate of Split-Thickness Skin Grafting of Chronic Venous Leg Ulcers Depends on the Presence of Pseudomonas aeruginosa: A Retrospective Study

The last years of research have proposed that bacteria might be involved in and contribute to the lack of healing of chronic wounds. Especially it seems that Pseudomonas aeruginosa play a crucial role in the healing. At Copenhagen Wound Healing Centre it was for many years clinical suspected that once chronic venous leg ulcers were colonized (weeks or months preoperatively) by P. aeruginosa, the success rate of skin grafting deteriorated despite aggressive treatment. To investigate this, a retrospective study was performed on the clinical outcome of 82 consecutive patients with chronic venous leg ulcers on 91 extremities, from the 1st of March 2005 until the 31st of August 2006. This was achieved by analysing the microbiology, demographic data, smoking and drinking habits, diabetes, renal impairment, co-morbidities, approximated size and age of the wounds, immunosuppressive treatment and complicating factors on the clinical outcome of each patient. The results were evaluated using a Student T-test for continuous parameters, chi-square test for categorical parameters and a logistic regression analysis to predict healing after 12 weeks. The analysis revealed that only 33,3% of ulcers with P. aeruginosa, isolated at least once from 12 weeks prior, to or during surgery, were healed (98% or more) by week 12 follow-up, while 73,1% of ulcers without P. aeruginosa were so by the same time (p = 0,001). Smoking also significantly suppressed the outcome at the 12-week follow-up. Subsequently, a logistic regression analysis was carried out leaving P. aeruginosa as the only predictor left in the model (p = 0,001). This study supports our hypothesis that P. aeruginosa in chronic venous leg ulcers, despite treatment, has considerable impact on partial take or rejection of split-thickness skin grafts

Antibiofilm Properties of Acetic Acid

Bacterial biofilms are known to be extremely tolerant toward antibiotics and other antimicrobial agents. These biofilms cause the persistence of chronic infections. Since antibiotics rarely resolve these infections, the only effective treatment of chronic infections is surgical removal of the infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram-negative biofilms using acetic acid both as a liquid and as a dry salt. In addition, we present our clinical experience of acetic acid treatment of chronic wounds. In conclusion, we here present the first comprehensive in vitro and in vivo testing of acetic acid against bacterial biofilms

ESCMID guideline for the diagnosis and treatment of biofilm infections 2014

AbstractBiofilms cause chronic infections in tissues or by developing on the surfaces of medical devices. Biofilm infections persist despite both antibiotic therapy and the innate and adaptive defence mechanisms of the patient. Biofilm infections are characterized by persisting and progressive pathology due primarily to the inflammatory response surrounding the biofilm. For this reason, many biofilm infections may be difficult to diagnose and treat efficiently. It is the purpose of the guideline to bring the current knowledge of biofilm diagnosis and therapy to the attention of clinical microbiologists and infectious disease specialists. Selected hallmark biofilm infections in tissues (e.g. cystic fibrosis with chronic lung infection, patients with chronic wound infections) or associated with devices (e.g. orthopaedic alloplastic devices, endotracheal tubes, intravenous catheters, indwelling urinary catheters, tissue fillers) are the main focus of the guideline, but experience gained from the biofilm infections included in the guideline may inspire similar work in other biofilm infections. The clinical and laboratory parameters for diagnosing biofilm infections are outlined based on the patient’s history, signs and symptoms, microscopic findings, culture-based or culture-independent diagnostic techniques and specific immune responses to identify microorganisms known to cause biofilm infections. First, recommendations are given for the collection of appropriate clinical samples, for reliable methods to specifically detect biofilms, for the evaluation of antibody responses to biofilms, for antibiotic susceptibility testing and for improvement of laboratory reports of biofilm findings in the clinical microbiology laboratory. Second, recommendations are given for the prevention and treatment of biofilm infections and for monitoring treatment effectiveness. Finally, suggestions for future research are given to improve diagnosis and treatment of biofilm infections

A novel chronic wound biofilm model sustaining coexistence of Pseudomonas aeruginosa

Chronic wounds are a large burden to patients and healthcare systems. Biofilm infections in chronic wounds are crucial factors leading to non‐healing of wounds. It is important to study biofilm in wounds and to develop effective interventions against wound biofilm. This study presents a novel in vitro biofilm model mimicking infected chronic wounds. The novel layered chronic wound biofilm model uses woundlike media and includes both Pseudomonas aeruginosa and Staphylococcus aureus, which have been identified as the most important pathogens in wounds. The model sustains their coexistence for at least 96 h. Microscopy of the model revealed microbial growth in non‐surface attached microcolonies as previously observed in vivo. The model was used to determine log(10)‐reduction for the use of an antimicrobial solution and antimicrobial dressings (containing silver or honey) showing moderate‐to‐low antibiofilm effect, which indicates better concordance with the observed clinical performance of this type of treatment than other widely used standard tests