Citation Details

Journal Article

Animals; Anti-Bacterial Agents; Bioware; Colony Count, Microbial; Mice; Mice, Inbred BALB C; Polymers; Prostheses and Implants; Rifampin; Silicone Elastomers; Staphylococcus aureus; Vancomycin; Xen29

OBJECTIVES Curing biomaterial-associated infection (BAI) frequently includes antibiotic treatment, implant removal and re-implantation. However, revision implants are at a greater risk of infection as they may attract bacteria from their infected surroundings. Polymer brush-coatings attract low numbers of bacteria, but the virtue of polymer brush-coatings in vivo has seldom been investigated. Here, we determine the possible benefits of polymer brush-coated versus pristine silicone rubber in revision surgery, using a murine model. METHODS BAI was induced in 26 mice by subcutaneous implantation of silicone rubber discs with a biofilm of Staphylococcus aureus Xen29. During the development of BAI, half of the mice received rifampicin/vancomycin treatment. After 5 days, the infected discs were removed from all mice, and either a polymer brush-coated or pristine silicone rubber disc was re-implanted. Revision discs were explanted after 5 days, and the number of cfu cultured from the discs and the surrounding tissue was determined. RESULTS None of the polymer brush-coated discs after antibiotic treatment appeared colonized by staphylococci, whereas 83% of the pristine silicone rubber discs were re-infected. Polymer brush-coated discs also showed reduced colonization rates in the absence of antibiotic treatment when compared with pristine silicone rubber discs. Tissue surrounding the discs was culture-positive in all cases. CONCLUSIONS Polymer brush-coatings are less prone to re-infection than pristine silicone rubber when used in revision surgery, i.e. when implanted in a subcutaneous pocket infected by a staphylococcal BAI. Antibiotic pre-treatment during the development of BAI hardly had any effect in preventing the colonization of pristine silicone rubber.

Journal Article

Animals; Anti-Infective Agents; Bandages; Biocompatible Materials; Bioware; Chitosan; Cyclophosphamide; Male; Mice; Mice, Inbred BALB C; Staphylococcal Skin Infections; Staphylococcus aureus; Wound Healing; Wound Infection; Xen8.1

HemCon bandage is an engineered chitosan acetate preparation designed as a hemostatic dressing, and is under investigation as a topical antimicrobial dressing. We studied its effects on healing of excisional wounds that were or were not infected with Staphylococcus aureus, in normal mice or mice previously pretreated with cyclophosphamide (CY). CY significantly suppressed wound healing in both the early and later stages, while S. aureus alone significantly stimulated wound healing in the early stages by preventing the initial wound expansion. CY plus S. aureus showed an advantage in early stages by preventing expansion, but a significant slowing of wound healing in later stages. In order to study the conflicting clamping and stimulating effects of chitosan acetate bandage on normal wounds, we removed the bandage from wounds at times after application ranging from 1 hour to 9 days. Three days application gave the earliest wound closure, and all application times gave a faster healing slope after removal compared with control wounds. Chitosan acetate bandage reduced the number of inflammatory cells in the wound at days 2 and 4, and had an overall beneficial effect on wound healing especially during the early period where its antimicrobial effect is most important.

Journal Article

Xen41, Xen39

N/A

Journal Article

IVIS, Xenogen, Xen10

Cyclic diguanylate (c-di-GMP) is a unique bacterial intracellular signaling molecule capable of stimulating enhanced protective innate immunity against various bacterial infections. The effects of intranasal pretreatment with c-di-GMP, or intraperitoneal coadministration of c-di-GMP with the pneumolysin toxoid (PdB) or pneumococcal surface protein A (PspA) before pneumococcal challenge, were investigated in mice. We found that c-di-GMP had no significant direct short-term effect on the growth rate of Streptococcus pneumoniae either in vitro or in vivo. However, intranasal pretreatment of mice with c-di-GMP resulted in a significant decrease in bacterial load in lungs and blood after serotypes 2 and 3 challenge, and a significant decrease in lung titers after serotype 4 challenge. Potential cellular mediators of these enhanced protective responses were identified in lungs and draining lymph nodes. Intraperitoneal coadministration of c-di-GMP with PdB or PspA before challenge resulted in significantly higher antigen-specific antibody titers and increased survival of mice, compared to that obtained with alum adjuvant. These findings demonstrate that local or systemic c-di-GMP administration stimulates innate and adaptive immunity against invasive pneumococcal disease. We propose that c-di-GMP can be used as an effective broad spectrum immunomodulator and vaccine adjuvant to prevent infectious diseases.

Journal Article

MMPSense, IVIS, Atherosclerosis/complications/*diagnosis; Carotid Stenosis/*diagnosis/etiology; Diagnostic Imaging/*methods; Humans; Reproducibility of Results

BACKGROUND: There is increasing evidence that plaque vulnerability, rather than the degree of stenosis, is important in predicting the occurrence of subsequent cerebral ischemic events in patients with carotid artery stenosis. The many imaging modalities currently available have different properties with regard to the visualization of the extent of vulnerability in carotid plaque formation. METHODS: Original published studies were identified using the MEDLINE database (January 1966 to March 2008). Manual cross-referencing was also performed. RESULTS: There is no single imaging modality that can produce definitive information about the state of vulnerability of an atherosclerotic plaque. Each has its own specific drawbacks, which may be the use of ionizing radiation or nephrotoxic contrast agents, an invasive character, low patient tolerability, or simply the paucity of information obtained on plaque vulnerability. Functional molecular imaging techniques such as positron emission tomography (PET), single photon emission-computed tomography (SPECT) and near infra-red spectroscopy (NIRS) do seem able accurately to visualize and even quantify features of plaque vulnerability and its pathophysiologic processes. Promising new techniques like near infra-red fluorescence imaging are being developed and may be beneficial in this field. CONCLUSION: There is a promising role for functional molecular imaging modalities like PET, SPECT, or NIRS related to improvement of selection criteria for carotid intervention, especially when combined with CT or MRI to add further anatomical details to molecular information. Further information will be needed to define whether and where this functional molecular imaging will fit into a clinical strategy.