Involvement of the Iron-Regulated Loci hts and fhuC in Biofilm Formation and Survival of Staphylococcus epidermidis within the Host

Staphylococcus epidermidis is one of the most important nosocomial pathogens and a major cause of central line-associated bloodstream infections. Once in the bloodstream, this bacterium must surpass severe iron restriction in order to survive and establish infection.

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Small Molecules Produced by Commensal Staphylococcus epidermidis Disrupt Formation of Biofilms by Staphylococcus aureus

Applied and Environmental Microbiology ◽

10.1128/aem.02539-19 ◽

2019 ◽

Vol 86 (5) ◽

Author(s):

Thaís Glatthardt ◽

Juliana Curityba de Mello Campos ◽

Raiane Cardoso Chamon ◽

Thiago Freitas de Sá Coimbra ◽

Giulia de Almeida Rocha ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Staphylococcus Epidermidis ◽

Biofilm Formation ◽

Bloodstream Infections ◽

Proteinase K ◽

Antibiofilm Activity ◽

Skin Microbiome ◽

Chronic Infections ◽

Content Type ◽

Treatment And Prevention

ABSTRACT The microbiota influences host health through several mechanisms, including protecting it from pathogen colonization. Staphylococcus epidermidis is one of the most frequently found species in the skin microbiota, and its presence can limit the development of pathogens such as Staphylococcus aureus. S. aureus causes diverse types of infections ranging from skin abscesses to bloodstream infections. Given the increasing prevalence of S. aureus drug-resistant strains, it is imperative to search for new strategies for treatment and prevention. Thus, we investigated the activity of molecules produced by a commensal S. epidermidis isolate against S. aureus biofilms. We showed that molecules present in S. epidermidis cell-free conditioned media (CFCM) caused a significant reduction in biofilm formation in most S. aureus clinical isolates, including all 4 agr types and agr-defective strains, without any impact on growth. S. epidermidis molecules also disrupted established S. aureus biofilms and reduced the antibiotic concentration required to eliminate them. Preliminary characterization of the active compound showed that its activity is resistant to heat, protease inhibitors, trypsin, proteinase K, and sodium periodate treatments, suggesting that it is not proteinaceous. RNA sequencing revealed that S. epidermidis-secreted molecules modulate the expression of hundreds of S. aureus genes, some of which are associated with biofilm production. Biofilm formation is one of the main virulence factors of S. aureus and has been associated with chronic infections and antimicrobial resistance. Therefore, molecules that can counteract this virulence factor may be promising alternatives as novel therapeutic agents to control S. aureus infections. IMPORTANCE S. aureus is a leading agent of infections worldwide, and its main virulence characteristic is the ability to produce biofilms on surfaces such as medical devices. Biofilms are known to confer increased resistance to antimicrobials and to the host immune responses, requiring aggressive antibiotic treatment and removal of the infected surface. Here, we investigated a new source of antibiofilm compounds, the skin microbiome. Specifically, we found that a commensal strain of S. epidermidis produces molecules with antibiofilm activity, leading to a significant decrease of S. aureus biofilm formation and to a reduction of previously established biofilms. The molecules potentiated the activity of antibiotics and affected the expression of hundreds of S. aureus genes, including those associated with biofilm formation. Our research highlights the search for compounds that can aid us in the fight against S. aureus infections.

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Fluid Flow Induces Biofilm Formation in Staphylococcus epidermidis Polysaccharide Intracellular Adhesin-Positive Clinical Isolates

Applied and Environmental Microbiology ◽

10.1128/aem.01139-12 ◽

2012 ◽

Vol 78 (16) ◽

pp. 5890-5896 ◽

Cited By ~ 35

Author(s):

Westbrook M. Weaver ◽

Vladana Milisavljevic ◽

Jeff F. Miller ◽

Dino Di Carlo

Keyword(s):

Fluid Flow ◽

Staphylococcus Epidermidis ◽

Biofilm Formation ◽

Hospital Costs ◽

Bloodstream Infections ◽

Clinical Isolates ◽

Content Type ◽

Biofilm Structure

ABSTRACTStaphylococcus epidermidisis a common cause of catheter-related bloodstream infections, resulting in significant morbidity and mortality and increased hospital costs. The ability to form biofilms plays a crucial role in pathogenesis; however, not all clinical isolates form biofilms under normalin vitroconditions. Strains containing theicaoperon can display significant phenotypic variation with respect to polysaccharide intracellular adhesin (PIA)-based biofilm formation, including the induction of biofilms upon environmental stress. Using a parallel microfluidic approach to investigate flow as an environmental signal forS. epidermidisbiofilm formation, we demonstrate that fluid shear alone induces PIA-positive biofilms of certain clinical isolates and influences biofilm structure. These findings suggest an important role of the catheter microenvironment, particularly fluid flow, in the establishment ofS. epidermidisinfections by PIA-dependent biofilm formation.

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A Single B-Repeat of Staphylococcus epidermidis Accumulation-Associated Protein Induces Protective Immune Responses in an Experimental Biomaterial-Associated Infection Mouse Model

Clinical and Vaccine Immunology ◽

10.1128/cvi.00306-14 ◽

2014 ◽

Vol 21 (9) ◽

pp. 1206-1214 ◽

Cited By ~ 12

Author(s):

Lin Yan ◽

Lei Zhang ◽

Hongyan Ma ◽

David Chiu ◽

James D. Bryers

Keyword(s):

Staphylococcus Epidermidis ◽

Biofilm Formation ◽

Porous Scaffold ◽

The United States ◽

Protein Vaccine ◽

Weight Changes ◽

Biofilm Inhibition ◽

Content Type ◽

Accumulation Associated Protein

ABSTRACTNosocomial infections are the fourth leading cause of morbidity and mortality in the United States, resulting in 2 million infections and ∼100,000 deaths each year. More than 60% of these infections are associated with some type of biomedical device.Staphylococcus epidermidisis a commensal bacterium of the human skin and is the most common nosocomial pathogen infecting implanted medical devices, especially those in the cardiovasculature.S. epidermidisantibiotic resistance and biofilm formation on inert surfaces make these infections hard to treat. Accumulation-associated protein (Aap), a cell wall-anchored protein ofS. epidermidis, is considered one of the most important proteins involved in the formation ofS. epidermidisbiofilm. A small recombinant protein vaccine comprising a single B-repeat domain (Brpt1.0) ofS. epidermidisRP62A Aap was developed, and the vaccine's efficacy was evaluatedin vitrowith a biofilm inhibition assay andin vivoin a murine model of biomaterial-associated infection. A high IgG antibody response againstS. epidermidisRP62A was detected in the sera of the mice after two subcutaneous immunizations with Brpt1.0 coadministered with Freund's adjuvant. Sera from Brpt1.0-immunized mice inhibitedin vitroS. epidermidisRP62A biofilm formation in a dose-dependent pattern. After receiving two immunizations, each mouse was surgically implanted with a porous scaffold disk containing 5 × 106CFU ofS. epidermidisRP62A. Weight changes, inflammatory markers, and histological assay results after challenge withS. epidermidisindicated that the mice immunized with Brpt1.0 exhibited significantly higher resistance toS. epidermidisRP62A implant infection than the control mice. Day 8 postchallenge, there was a significantly lower number of bacteria in scaffold sections and surrounding tissues and a lower residual inflammatory response to the infected scaffold disks for the Brpt1.0-immunized mice than for of the ovalbumin (Ova)-immunized mice.

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Growth Retardation, Reduced Invasiveness, and Impaired Colistin-Mediated Cell Death Associated with Colistin Resistance Development in Acinetobacter baumannii

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01439-13 ◽

2013 ◽

Vol 58 (2) ◽

pp. 828-832 ◽

Cited By ~ 54

Author(s):

Spyros Pournaras ◽

Aggeliki Poulou ◽

Konstantina Dafopoulou ◽

Yassine Nait Chabane ◽

Ioulia Kristo ◽

...

Keyword(s):

Cell Death ◽

Acinetobacter Baumannii ◽

Biofilm Formation ◽

Bloodstream Infections ◽

Single Amino Acid ◽

Colistin Resistance ◽

Resistance Development ◽

Content Type ◽

Alkyl Hydroperoxide ◽

Severe Soft Tissue

ABSTRACTTwo colistin-susceptible/colistin-resistant (Cols/Colr) pairs ofAcinetobacter baumanniistrains assigned to international clone 2, which is prevalent worldwide, were sequentially recovered from two patients after prolonged colistin administration. Compared with the respective Colsisolates (Ab248 and Ab299, both having a colistin MIC of 0.5 μg/ml), both Colrisolates (Ab249 and Ab347, with colistin MICs of 128 and 32 μg/ml, respectively) significantly overexpressedpmrCABgenes, had single-amino-acid shifts in the PmrB protein, and exhibited significantly slower growth. The Colrisolate Ab347, tested by proteomic analysis in comparison with its Colscounterpart Ab299, underexpressed the proteins CsuA/B and C from thecsuoperon (which is necessary for biofilm formation). This isolate also underexpressed aconitase B and different enzymes involved in the oxidative stress response (KatE catalase, superoxide dismutase, and alkyl hydroperoxide reductase), suggesting a reduced response to reactive oxygen species (ROS) and, consequently, impaired colistin-mediated cell death through hydroxyl radical production. Colsisolates that were indistinguishable by macrorestriction analysis from Ab299 caused six sequential bloodstream infections, and isolates indistinguishable from Ab248 caused severe soft tissue infection, while Colrisolates indistinguishable from Ab347 and Ab249 were mainly colonizers. In particular, a Colsisolate identical to Ab299 was still invading the bloodstream 90 days after the colonization of this patient by Colrisolates. These observations indicate considerably lower invasiveness ofA. baumanniiclinical isolates following the development of colistin resistance.

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Clinical Evaluation of the iCubate iC-GPC Assay for Detection of Gram-Positive Bacteria and Resistance Markers from Positive Blood Cultures

Journal of Clinical Microbiology ◽

10.1128/jcm.00485-18 ◽

2018 ◽

Vol 56 (9) ◽

Cited By ~ 5

Author(s):

Paul A. Granato ◽

Melissa M. Unz ◽

Raymond H. Widen ◽

Suzane Silbert ◽

Stephen Young ◽

...

Keyword(s):

Blood Culture ◽

Staphylococcus Epidermidis ◽

Bloodstream Infections ◽

Blood Cultures ◽

Gram Positive ◽

Content Type ◽

Gram Positive Bacteria ◽

Sequencing Method ◽

Resistance Markers ◽

Gram Positive Cocci

ABSTRACT The iC-GPC Assay (iCubate, Huntsville, AL) is a qualitative multiplex test for the detection of five of the most common Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Enterococcus faecalis, and Enterococcus faecium) responsible for bacterial bloodstream infections, performed directly from positive blood cultures. The assay also detects the presence of the mecA, vanA, and vanB resistance determinants. This study comparatively evaluated the performance of the iC-GPC Assay against the Verigene Gram-positive blood culture (BC-GP) assay (Luminex Corp., Austin, TX) for 1,134 patient blood culture specimens positive for Gram-positive cocci. The iC-GPC Assay had an overall percent agreement with the BC-GP assay of 95.5%. Discordant specimens were further analyzed by PCR and a bidirectional sequencing method. The results indicate that the iC-GPC Assay together with the iCubate system is an accurate and reliable tool for the detection of the five most common Gram-positive bacteria and their resistance markers responsible for bloodstream infections.

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Minocycline-EDTA-Ethanol Antimicrobial Catheter Lock Solution Is Highly Effective In Vitro for Eradication of Candida auris Biofilms

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02146-19 ◽

2020 ◽

Vol 64 (4) ◽

Author(s):

Ruth A. Reitzel ◽

Joel Rosenblatt ◽

Bahgat Z. Gerges ◽

Nylev Vargas-Cruz ◽

Issam I. Raad

Keyword(s):

Therapeutic Option ◽

Bloodstream Infections ◽

Central Line ◽

Emerging Pathogen ◽

Candida Auris ◽

Content Type ◽

Lock Solution ◽

Highly Effective ◽

Catheter Lock

ABSTRACT Candida auris is an emerging pathogen that can cause virulent central-line-associated bloodstream infections. Catheter salvage through the eradication of biofilms is a desirable therapeutic option. We compared taurolidine and minocycline-EDTA-ethanol (MEE) catheter lock solutions in vitro for the eradication of biofilms of 10 C. auris strains. MEE fully eradicated all C. auris biofilms, while taurolidine lock partially eradicated all of the C. auris biofilms. The superiority was significant for all C. auris strains tested (P = 0.002).

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Disparate Candida albicans Biofilm Formation in Clinical Lipid Emulsions Due to Capric Acid-Mediated Inhibition

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01394-19 ◽

2019 ◽

Vol 63 (11) ◽

Author(s):

Hubertine M. E. Willems ◽

Jeremy S. Stultz ◽

Molly E. Coltrane ◽

Jabez P. Fortwendel ◽

Brian M. Peters

Keyword(s):

Candida Albicans ◽

Biofilm Formation ◽

Bloodstream Infections ◽

Capric Acid ◽

Lipid Emulsions ◽

Biofilm Growth ◽

Content Type ◽

Biofilm Model ◽

Hypha Formation

ABSTRACT Receipt of parenteral nutrition (PN) remains an independent risk factor for developing catheter-related bloodstream infections (CR-BSI) caused by fungi, including by the polymorphic fungus Candida albicans, which is notoriously adept at forming drug-resistant biofilm structures. Among a variety of macronutrients, PN solutions contain lipid emulsions to supply daily essential fats and are often delivered via central venous catheters (CVCs). Therefore, using an in vitro biofilm model system, we sought to determine whether various clinical lipid emulsions differentially impacted biofilm growth in C. albicans. We observed that the lipid emulsions Intralipid and Omegaven both stimulated C. albicans biofilm formation during growth in minimal medium or a macronutrient PN solution. Conversely, Smoflipid inhibited C. albicans biofilm formation by approximately 50%. Follow-up studies revealed that while Smoflipid did not impair C. albicans growth, it did significantly inhibit hypha formation and hyphal elongation. Moreover, growth inhibition could be recapitulated in Intralipid when supplemented with capric acid—a fatty acid present in Smoflipid but absent in Intralipid. Capric acid was also found to dose dependently inhibit C. albicans biofilm formation in PN solutions. This is the first study to directly compare different clinical lipid emulsions for their capacity to affect C. albicans biofilm growth. Results derived from this study necessitate further research regarding different lipid emulsions and rates of fungus-associated CR-BSIs.

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Accumulation-Associated Protein Enhances Staphylococcus epidermidis Biofilm Formation under Dynamic Conditions and Is Required for Infection in a Rat Catheter Model

Infection and Immunity ◽

10.1128/iai.02177-14 ◽

2014 ◽

Vol 83 (1) ◽

pp. 214-226 ◽

Cited By ~ 63

Author(s):

Carolyn R. Schaeffer ◽

Keith M. Woods ◽

G. Matt Longo ◽

Megan R. Kiedrowski ◽

Alexandra E. Paharik ◽

...

Keyword(s):

Staphylococcus Epidermidis ◽

Biofilm Formation ◽

Host Cells ◽

Content Type ◽

Microtiter Plates ◽

Allelic Replacement ◽

Abiotic Surfaces ◽

Cell Accumulation ◽

Accumulation Associated Protein

Biofilm formation is the primary virulence factor ofStaphylococcus epidermidis.S. epidermidisbiofilms preferentially form on abiotic surfaces and may contain multiple matrix components, including proteins such as accumulation-associated protein (Aap). Following proteolytic cleavage of the A domain, which has been shown to enhance binding to host cells, B domain homotypic interactions support cell accumulation and biofilm formation. To further define the contribution of Aap to biofilm formation and infection, we constructed anaapallelic replacement mutant and anicaADBC aapdouble mutant. When subjected to fluid shear, strains deficient in Aap production produced significantly less biofilm than Aap-positive strains. To examine thein vivorelevance of our findings, we modified our previously described rat jugular catheter model and validated the importance of immunosuppression and the presence of a foreign body to the establishment of infection. The use of our allelic replacement mutants in the model revealed a significant decrease in bacterial recovery from the catheter and the blood in the absence of Aap, regardless of the production of polysaccharide intercellular adhesin (PIA), a well-characterized, robust matrix molecule. Complementation of theaapmutant with full-length Aap (containing the A domain), but not the B domain alone, increased initial attachment to microtiter plates, as did intransexpression of the A domain in adhesion-deficientStaphylococcus carnosus. These results demonstrate Aap contributes toS. epidermidisinfection, which may in part be due to A domain-mediated attachment to abiotic surfaces.

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Extracellular DNA Impedes the Transport of Vancomycin in Staphylococcus epidermidis Biofilms Preexposed to Subinhibitory Concentrations of Vancomycin

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03132-14 ◽

2014 ◽

Vol 58 (12) ◽

pp. 7273-7282 ◽

Cited By ~ 61

Author(s):

Natalya Doroshenko ◽

Boo Shan Tseng ◽

Robert P. Howlin ◽

Jill Deacon ◽

Julian A. Wharton ◽

...

Keyword(s):

Confocal Microscopy ◽

Isothermal Titration Calorimetry ◽

Staphylococcus Epidermidis ◽

Binding Constant ◽

Biofilm Formation ◽

Potential Role ◽

Extracellular Dna ◽

Titration Calorimetry ◽

Orthopedic Implant ◽

Content Type

ABSTRACTStaphylococcus epidermidisbiofilm formation is responsible for the persistence of orthopedic implant infections. Previous studies have shown that exposure ofS. epidermidisbiofilms to sub-MICs of antibiotics induced an increased level of biofilm persistence. BODIPY FL-vancomycin (a fluorescent vancomycin conjugate) and confocal microscopy were used to show that the penetration of vancomycin through sub-MIC-vancomycin-treatedS. epidermidisbiofilms was impeded compared to that of control, untreated biofilms. Further experiments showed an increase in the extracellular DNA (eDNA) concentration in biofilms preexposed to sub-MIC vancomycin, suggesting a potential role for eDNA in the hindrance of vancomycin activity. Exogenously added,S. epidermidisDNA increased the planktonic vancomycin MIC and protected biofilm cells from lethal vancomycin concentrations. Finally, isothermal titration calorimetry (ITC) revealed that the binding constant of DNA and vancomycin was 100-fold higher than the previously reported binding constant of vancomycin and its intended cellulard-Ala-d-Ala peptide target. This study provides an explanation of the eDNA-based mechanism of antibiotic tolerance in sub-MIC-vancomycin-treatedS. epidermidisbiofilms, which might be an important factor for the persistence of biofilm infections.

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Oral Administration of the Broad-Spectrum Antibiofilm Compound Toremifene Inhibits Candida albicans and Staphylococcus aureus Biofilm FormationIn Vivo

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03869-14 ◽

2014 ◽

Vol 58 (12) ◽

pp. 7606-7610 ◽

Cited By ~ 16

Author(s):

Kaat De Cremer ◽

Nicolas Delattin ◽

Katrijn De Brucker ◽

Annelies Peeters ◽

Soña Kucharíková ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Candida Albicans ◽

Broad Spectrum ◽

Staphylococcus Epidermidis ◽

Biofilm Formation ◽

Candida Krusei ◽

Content Type ◽

And Staphylococcus Aureus

ABSTRACTWe here report on thein vitroactivity of toremifene to inhibit biofilm formation of different fungal and bacterial pathogens, includingCandida albicans,Candida glabrata,Candida dubliniensis,Candida krusei,Pseudomonas aeruginosa,Staphylococcus aureus, andStaphylococcus epidermidis. We validated thein vivoefficacy of orally administered toremifene againstC. albicans and S. aureusbiofilm formation in a rat subcutaneous catheter model. Combined, our results demonstrate the potential of toremifene as a broad-spectrum oral antibiofilm compound.

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