Expression of toll ‐like receptors in T lymphocytes stimulated with N‐(3‐oxododecanoyl)‐L‐homoserine lactone from Pseudomonas aeruginosa
The establishment of chronic Pseudomonas aeruginosa infections is correlated with the disturbance of the host immune system. The P. aeruginosa quorum‐sensing molecule N‐3‐(oxododecanoyl)‐L‐homoserine lactone (3‐O‐C12‐HSL) has the potential to modulate the host immune system. The immune system recognizes pathogens via toll‐like receptors (TLRs). We found that 3‐O‐C12‐HSL induced TLR changes in monocytes. However, the role of T cells in P. aeruginosa infection has not been delineated. In order to understand this activity, we examined whether 3‐O‐C12‐HSL has an effect on the immune function and t...
Source: APMIS - April 18, 2017 Category: Research Authors: Lei Bao, Jialin Yu, Haiying Zhong, Daochao Huang, Qi Lu Tags: Original Article Source Type: research
Assessment of biofilm removal capacity of a broad host range bacteriophage JHP against Pseudomonas aeruginosa
Pseudomonas aeruginosa is an efficient biofilm‐dwelling microbial pathogen, associated with nosocomial infections. These biofilm‐associated infections are resistant to antibiotics and immune defenses, therefore pose major problem against their treatment. This scenario demands alternative therapeutic regimens, and bacteriophage therapy is one among potential strategies for clinical management of multiple drug resistance. In this investigation, the efficacy of a bacteriophage, JHP, is evaluated to eradicate P. aeruginosa biofilms. Growth kinetics of P. aeruginosa biofilm revealed that the highest cell density biofilm (1....
Source: APMIS - April 18, 2017 Category: Research Authors: Muafia Shafique, Iqbal Ahmad Alvi, Zaigham Abbas, Shafiq Rehman Tags: Original Article Source Type: research
Biofilms in orthopedic infections: a review of laboratory methods
Bacterial infection after hardware implantation in orthopedic surgery is a devastating issue as it often necessitates increased hospital costs and stays, multiple revision surgeries, and prolonged use of antibiotics. Because of the nature of hardware implantation into the body, these infections are commonly in the form of attached biofilms. The current literature on a range of methodologies to study clinically explanted infected orthopedic hardware, with potential biofilm, in the laboratory setting is limited. General methods include traditional and advanced culturing techniques, microscopy imaging techniques, and techniqu...
Source: APMIS - April 13, 2017 Category: Research Authors: Alex C. Dibartola, Matthew C. Swearingen, Jeffrey F. Granger, Paul Stoodley, Devendra H. Dusane Tags: Review Article Source Type: research
Antifouling and antimicrobial biomaterials: an overview
The use of implantable medical devices is a common and indispensable part of medical care for both diagnostic and therapeutic purposes. However, as side effect, the implant of medical devices quite often leads to the occurrence of difficult‐to‐treat infections, as a consequence of the colonization of their abiotic surfaces by biofilm‐growing microorganisms increasingly resistant to antimicrobial therapies. A promising strategy to combat device‐related infections is based on anti‐infective biomaterials that either repel microbes, so they cannot attach to the device surfaces, or kill them in the surrounding areas. ...
Source: APMIS - April 13, 2017 Category: Research Authors: Iolanda Francolini, Claudia Vuotto, Antonella Piozzi, Gianfranco Donelli Tags: Review Article Source Type: research
Chronic urinary tract infections in patients with spinal cord lesions – biofilm infection with need for long‐term antibiotic treatment
Patients suffering from spinal cord injuries resulting in complete or incomplete paraplegia or tetraplegia are highly disposed to frequent, recurrent or even chronic urinary tract infections (UTIs). The reason for the increased risk of acquiring UTIs is multifactorial, including reduced sensation of classical UTI symptoms, incomplete bladder emptying, frequent catheterizations or chronic urinary tract catheters. Biofilms in relation to UTIs have been shown both on catheters, on concrements or as intracellular bacterial communities (IBCs). Due to the increased risk of acquiring recurrent or chronic UTIs and frequent antibio...
Source: APMIS - April 13, 2017 Category: Research Authors: Nete Tofte, Alex C. Y. Nielsen, Hannah Tr østrup, Christine B. Andersen, Michael Von Linstow, Birgitte Hansen, Fin Biering‐Sørensen, Niels Høiby, Claus Moser Tags: Review Article Source Type: research
Dental biofilm infections – an update
Teeth are colonized by oral bacteria from saliva containing more than 700 different bacterial species. If removed regularly, the dental biofilm mainly comprises oral streptococci and is regarded as resident microflora. But if left undisturbed, a complex biofilm containing up to 100 bacterial species at a site will build up and may eventually cause development of disease. Depending on local ecological factors, the composition of the dental biofilm may vary considerably. With access to excess carbohydrates, the dental biofilm will be dominated by mainly gram‐positive carbohydrate‐fermenting bacteria causing demineralizat...
Source: APMIS - April 13, 2017 Category: Research Authors: Tove Larsen, Nils ‐Erik Fiehn Tags: Review Article Source Type: research
Central venous catheters and biofilms: where do we stand in 2017?
The use of central venous catheters (CVC) is associated with a risk of microbial colonization and subsequent potentially severe infection. Microbial contamination of the catheter leads to the development of a microbial consortia associated with the CVC surface and embedded in an extracellular matrix, named biofilm. This biofilm provides bacterial cells the ability to survive antimicrobial agents and the host immune system and to disseminate to other sites of the body. The best preventive strategy is to avoid any unnecessary catheterization or to reduce indwelling duration when a CVC is required. Beside aseptic care and ant...
Source: APMIS - April 13, 2017 Category: Research Authors: Marie Gominet, Fabrice Compain, Christophe Beloin, David Lebeaux Tags: Review Article Source Type: research
Orthopaedic biofilm infections
Many infections of the musculoskeletal system are biofilm infections that develop on non‐living surfaces. Microorganisms adhere either on dead bone (sequesters) or implants. As a rule for a curative concept, chronic osteomyelitis or implant‐associated bone infection must be treated with a combination of surgery and antimicrobial therapy. If an implant is kept in place, or a new device is implanted before complete healing of infection, a biofilm‐active antibiotic should be used. Rifamycins are active against biofilms of staphylococci, and fluoroquinolones against those of Gram‐negative bacilli. In this review, the m...
Source: APMIS - April 13, 2017 Category: Research Authors: Werner Zimmerli, Parham Sendi Tags: Review Article Source Type: research
In vitro studies evaluating the effects of biofilms on wound ‐healing cells: a review
Chronic wounds are characterized as wounds that have failed to proceed through the well‐orchestrated healing process and have remained open for months to years. Open wounds are at risk for colonization by opportunistic pathogens. Bacteria that colonize the open wound bed form surface‐attached, multicellular communities called biofilms, and chronic wound biofilms can contain a diverse microbiota. Investigators are just beginning to elucidate the role of biofilms in chronic wound pathogenesis, and have simplified the complex wound environment using in vitro models to obtain a fundamental understanding of the impact of b...
Source: APMIS - April 13, 2017 Category: Research Authors: Kelly R. Kirker, Garth A. James Tags: Review Article Source Type: research
Diagnosis of biofilm infections in cystic fibrosis patients
Chronic Pseudomonas aeruginosa biofilm lung infection in cystic fibrosis patients is the best described biofilm infection in medicine. The initial focus can be the paranasal sinuses and then follows repeated colonization and infection of the lungs by aspiration. The matrix of the biofilms is dominated by alginate and the pathogenesis of tissue damage is immune complex‐mediated chronic inflammation dominated by polymorphonuclear leukocytes and their products (DNA, oxygen radicals and proteases). The P. aeruginosa biofilm infection can be diagnosed by microscopy of lung tissue, sputum and mucus from the paranasal sinuses,...
Source: APMIS - April 13, 2017 Category: Research Authors: Niels H øiby, Thomas Bjarnsholt, Claus Moser, Peter Østrup Jensen, Mette Kolpen, Tavs Qvist, Kasper Aanæs, Tanja Pressler, Marianne Skov, Oana Ciofu Tags: Review Article Source Type: research
Biofilms and host response – helpful or harmful
Biofilm infections are one of the modern medical world's greatest challenges. Probably, all non‐obligate intracellular bacteria and fungi can establish biofilms. In addition, there are numerous biofilm‐related infections, both foreign body‐related and non‐foreign body‐related. Although biofilm infections can present in numerous ways, one common feature is involvement of the host response with significant impact on the course. A special characteristic is the synergy of the innate and the acquired immune responses for the induced pathology. Here, we review the impact of the host response for the course of biofilm i...
Source: APMIS - April 13, 2017 Category: Research Authors: Claus Moser, Hannah Tr østrup Pedersen, Christian Johann Lerche, Mette Kolpen, Laura Line, Kim Thomsen, Niels Høiby, Peter Østrup Jensen Tags: Review Article Source Type: research
Antibiotic treatment of biofilm infections
Bacterial biofilms are associated with a wide range of infections, from those related to exogenous devices, such as catheters or prosthetic joints, to chronic tissue infections such as those occurring in the lungs of cystic fibrosis patients. Biofilms are recalcitrant to antibiotic treatment due to multiple tolerance mechanisms (phenotypic resistance). This causes persistence of biofilm infections in spite of antibiotic exposure which predisposes to antibiotic resistance development (genetic resistance). Understanding the interplay between phenotypic and genetic resistance mechanisms acting on biofilms, as well as apprecia...
Source: APMIS - April 13, 2017 Category: Research Authors: Oana Ciofu, Estrella Rojo ‐Molinero, María D. Macià, Antonio Oliver Tags: Review Article Source Type: research
Microbiological diagnosis of device ‐related biofilm infections
Medical device‐related infections cause undue patient distress, increased morbidity and mortality and pose a huge financial burden on healthcare services. The pathogens are frequently distributed heterogeneously in biofilms, which can persist without being effectively cleared by host immune defenses and antibiotic therapy. At present, there is no ‘gold standard’ available to reveal the presence of device‐related biofilm infections. However, adequate sample collection and logistics, standardised diagnostic methods, and interpretation of results by experienced personnel are important steps in efficient diagnosis and ...
Source: APMIS - April 13, 2017 Category: Research Authors: Yijuan Xu, Lone Heimann Larsen, Jan Lorenzen, Luanne Hall ‐Stoodley, Judith Kikhney, Annette Moter, Trine Rolighed Thomsen Tags: Review Article Source Type: research
Microenvironmental characteristics and physiology of biofilms in chronic infections of CF patients are strongly affected by the host immune response
In vitro studies of Pseudomonas aeruginosa and other pathogenic bacteria in biofilm aggregates have yielded detailed insight into their potential growth modes and metabolic flexibility under exposure to gradients of substrate and electron acceptor. However, the growth pattern of P. aeruginosa in chronic lung infections of cystic fibrosis (CF) patients is very different from what is observed in vitro, for example, in biofilms grown in flow chambers. Dense in vitro biofilms of P. aeruginosa exhibit rapid O2 depletion within <50–100 μm due to their own aerobic metabolism. In contrast, in vivo investigations show t...
Source: APMIS - April 13, 2017 Category: Research Authors: Peter Ø. Jensen, Mette Kolpen, Kasper N. Kragh, Michael Kühl Tags: Review Article Source Type: research
A short history of microbial biofilms and biofilm infections
The observation of aggregated microbes surrounded by a self‐produced matrix adhering to surfaces or located in tissues or secretions is old since both Leeuwenhoek and Pasteur have described the phenomenon. In environmental and technical microbiology, biofilms, 80–90 years ago, were already shown to be important for biofouling on submerged surfaces, for example, ships. The concept of biofilm infections and their importance in medicine was, however, initiated in the early 1970s by the observation of heaps of Pseudomonas aeruginosa cells in sputum and lung tissue from chronically infected cystic fibrosis patients. The te...
Source: APMIS - April 13, 2017 Category: Research Authors: Niels H øiby Tags: Review Article Source Type: research
