Catheter biofilm

S. aureus is a leading cause of device-associated biofilm infections, which represent a serious health care concern based on their chronicity and antibiotic resistance. We previously reported that S. aureus biofilms preferentially recruit myeloid-derived suppressor cells (MDSCs), which promote monocyte and macrophage anti-inflammatory properties. This is associated with increased myeloid arginase-1 (Arg-1) expression, which has been linked to anti-inflammatory and pro-fibrotic activity that are observed during S...

Ethanol-based lock therapy (LT) solutions are used as an alternative to antibiotics for the conservative management of catheter-related bloodstream infection. However, no clear consensus on regimen or dose has been reached. Our objective was to find the ethanol-based lock solution containing a sufficiently low concentration of ethanol for reduction of the metabolic activity of bacterial and fungal biofilms. Using an in vitro model, we tested 3 concentrations of ethanol (25%-40%-70%), with and without 60 IU of heparin, at 6 different time points and against 24-hour preformed biofilms of Staphylococcus aureus ATCC29213, Staphylococcus epidermidis (clinical isolate), Enterococcus faecalis ATCC33186, Candida albicans ATCC14058, and Escherichia coli ATCC25922...

Fungal infections are a major problem for a growing number of mostly immune-compromised patients. Candida albicans is an important human fungal pathogen causing mucosal and deep tissue infections of which the majority is associated with biofilm formation on medical implants. The animal models that are currently in use to test antifungal drugs are limited to ex vivo analyses, requiring host sacrifice that excludes longitudinal monitoring of dynamic processes during biofilm formation in the live host. As a solution, we introduce non-invasive, dynamic imaging and quantification of C...

Two-component systems (TCS) are modular signal transduction pathways that allow cells to adapt to prevailing environmental conditions by modifying cellular physiology. Staphylococcus aureus has 16 TCSs to adapt to the diverse microenvironments encountered during its life cycle, including host tissues and implanted medical devices. S. aureus is particularly prone to cause infections associated to medical devices, whose surfaces coated by serum proteins constitute a particular environment. Identification of the TCSs involved in the adaptation of S...

Numerous bacteria utilize molecular communication systems referred to as quorum sensing (QS) to synchronize the expression of certain genes regulating, among other aspects, the expression of virulence factors and the synthesis of biofilm. To achieve this process, bacteria use signaling molecules, known as autoinducers (AIs), as chemical messengers to share information. Naturally occurring strategies that interfere with bacterial signaling have been extensively studied in recent years, examining their potential to control bacteria...

Acinetobacter baumannii causes serious hospital-acquired infections and has been positioned as a priority organism by the World Health Organization. This study includes 36 A. baumannii isolates from a children hospital recovered between March 2014 and May 2015 in Cochabamba. The majority of the isolates were recovered from blood cultures (n=10, 31.3%) and respiratory samples (n=11, 34.4%); fifty three percent of the patients were younger than one month old. Most of these isolates (n=30, 80.6%) were extremely-drug resistant (XDR) and 8...

To evaluate the pathophysiology of catheter-associated candiduria, the bladders of female mice were infected with Candida tropicalis. One group was implanted with a catheter fragment with preformed biofilm by cystotomy technique, while another group received, in separate, a sterile catheter fragment and a correspondent yeast suspension. The bladder tissues were examined by histopathology and the quantity of colony forming units was evaluated. All the animals presented inflammation and the presence of C. tropicalis was observed in the tissue within 72 h of the introduction of biofilm, while 75% of the mice remained infected after 144 h...

BACKGROUND/AIMS: N-acetylcysteine (NAC) is a novel and promising agent with activity against bacterial biofilms. Human serum also inhibits biofilm formation by some bacteria. We tested whether the combination of NAC and human serum offers greater anti-biofilm activity than either agent alone. METHODS: Microtiter plate assays and confocal laser scanning microscopy were used to evaluate bacterial biofilm formation in the presence of NAC and human serum. qPCR was used to examine expression of selected biofilm-associated genes...

Klebsiella pneumoniae and Escherichia coli form mixed species biofilms in catheter-associated urinary tract infections. Recently, a detrimental effect of K. pneumoniae over E. coli was observed in mixed species biofilms grown in an artificial urine medium. The mechanism behind this competitive interaction was studied. K. pneumoniae partially outcompeted E. coli in early-stage batch-fed biofilms, whereas both microorganisms co-exist at longer times (K. pneumoniae:E. coli ratio, 55:1), as shown by cell counts and confocal microscopy...

Chronic kidney disease (CKD) is associated with an imbalanced human microbiome due not only to CKD-associated factors such as uremia, increased inflammation and immunosuppression, but also to pharmacological therapies and dietary restrictions. End-stage renal disease patients require renal replacement therapies commonly in the form of hemodialysis (HD) or peritoneal dialysis (PD). HD implies the existence of a vascular access, such as an arteriovenous fistula/graft or a venous catheter, whereas PD implies a long-term peritoneal catheter and the constant inflow of peritoneal dialysate...

Formation of crystalline biofilms following infection by Proteus mirabilis can lead to encrustation and blockage of long-term indwelling catheters, with serious clinical consequences. We describe a simple sensor, placed within the catheter drainage bag, to alert of impending blockage via a urinary color change. The pH-responsive sensor is a dual-layered polymeric "lozenge", able to release the self-quenching dye 5(6)-carboxyfluorescein in response to the alkaline urine generated by the expression of bacterial urease...

Staphylococcus epidermidis is a gram-positive bacterium, and one of the most prevalent causes of nosocomial infections due to its strong ability to form biofilms on catheters and surgical implants. Here we explore the antimicrobial properties of Tet-124 peptides, which are part of the innate defense against different multicellular organisms in nature. Two different Tet-124 peptides were immobilized on a polyethylenimine (PEI) film to determine their impact on the antimicrobial properties: KLWWMIRRW (Tet-124), which contains only natural amino acids, and KLWWMIRRWG-(F-Br)-G (F-Br = 4-Bromophenylalanine), a modified Tet-124 sequence with the addition of an unnatural amino acid...

Central venous catheters (CVCs) are ubiquitous in the healthcare industry and carry two common complications, catheter related infections and occlusion, particularly by thrombus. Catheter-related bloodstream infections (CRBSI) are an important cause of nosocomial infections that increase patient morbidity, mortality, and hospital cost. Innovative design strategies for intravenous catheters can help reduce these preventable infections. Antimicrobial coatings can play a major role in preventing disease. These coatings can be divided into two major categories: drug eluting and non-drug eluting...

Fungal catheter-related bloodstream infections (CRBSIs)-primarily due to Candida species-account for over 12% of all CRBSIs, and have been progressively increasing in prevalence. They present significant health and economic burdens, and high mortality rates. Antimicrobial catheter lock solutions are an important prophylactic option for preventing fungal CRBSIs. In this study, we compared the effectiveness of two FDA-approved catheter lock solutions (heparin and saline) and three experimental antimicrobial catheter lock solutions-30% citrate, taurolidine-citrate-heparin (TCH), and nitroglycerin-citrate-ethanol (NiCE)-in an in vitro model of catheters colonized by fungi...

Despite the advantages of extracorporeal membrane oxygenation (ECMO), secondary catheter infection remains a major concern during ECMO support. In this study, to clarify the mechanism of ECMO catheter-related infection, we evaluated the impact of infection on biofilm formation on the surfaces of ECMO catheters, and we investigated clinical factors associated with biofilm formation. Catheters used for ECMO were prospectively collected aseptically from the femoral vein, internal jugular vein, and femoral artery of 81 patients with acute cardiorespiratory failure between January 2015 and October 2016...

Candidemia related to the presence of a biofilm are often reported in patients with vascular catheters. Once they are mature, biofilms are persistent infectious reservoirs, and the yeasts dispersed from biofilms can cause infections. Sessile yeasts typically display increased levels of resistance to most antimicrobial agents and systemic treatments usually fail to eradicate previously formed fungal biofilms. In a curative strategy, antifungal lock therapy may help to sterilize catheters, with very high concentrations of antifungal agents, which are not compatible with systemic use...

BACKGROUND: Candidemia is one of the most common nosocomial infections globally and it is associated with considerable excess mortality and costs. Abreast, biofilm-forming strains are associated with even higher mortality rates and poor prognosis for the patient. AIMS: To evaluate a possible association between the biofilm-forming capability of Candida bloodstream isolates and the clinical evolution in patients with candidemia. METHODS: An observational, retrospective study was conducted at a tertiary care university hospital during 9 years (2006-2015)...

BACKGROUND: Trichosporon asahii is a yeast-like fungus that has recently gained importance as a cause of opportunistic systemic infections. The pathogenicity and virulence factors of T. asahii remain largely unknown. Because of the association between invasive infections and the use of catheters and related devices, the ability of the microorganism to adhere and form biofilms may play an important role in the pathogenicity during a trichosporonosis. AIMS: The aim of this study is to identify an association between biofilm formation by T...

Candida albicans is the most common fungal pathogen of humans, causing about 15% of hospital-acquired sepsis cases. A major virulence attribute of C. albicans is its ability to form biofilms, structured communities of cells attached to biotic and abiotic surfaces. C. albicans biofilms can form on host tissues, such as mucosal layers, and on medical devices, such as catheters, pacemakers, dentures, and joint prostheses. Biofilms pose significant clinical challenges because they are highly resistant to physical and chemical perturbations, and can act as reservoirs to seed disseminated infections...

There are few therapeutic options to simultaneously tackle Staphylococcus aureus and Pseudomonas aeruginosa, two of the most relevant nosocomial and antibiotic-resistant pathogens responsible for implant, catheters and wound severe infections. The design and synthesis of polymers with inherent antimicrobial activity have gained increasing attention as a safe strategy to treat multi-drug-resistant microbes. Here, we tested the activity of a new polymeric derivative with glycopolypeptide architecture (PAA-VC) bearing l-arginine, vancomycin, and colistin as side chains acting against multiple targets, which give rise to a broad spectrum antimicrobial activity favorably combining specific and nonspecific perturbation of the bacterial membrane...