scholarly journals Impact of Extracellular Nuclease Production on the Biofilm Phenotype of Staphylococcus aureus underIn VitroandIn VivoConditions

2012 ◽  
Vol 80 (5) ◽  
pp. 1634-1638 ◽  
Author(s):  
Karen E. Beenken ◽  
Horace Spencer ◽  
Linda M. Griffin ◽  
Mark S. Smeltzer
Keyword(s):  
Staphylococcus Aureus ◽  
Murine Model ◽  
Biofilm Formation ◽  
Extracellular Dna ◽  
Content Type ◽  
Extracellular Nuclease ◽  
The Impact ◽  
Increased Susceptibility

ABSTRACTRecent studies suggest that extracellular DNA promotes biofilm formation inStaphylococcus aureusand, conversely, that extracellular nucleases limit the ability to form a biofilm.S. aureusproduces at least two extracellular nucleases, and in the study described in this report, we examined the impact of each of these nucleases on biofilm formation under bothin vitroandin vivoconditions. Our results demonstrate that both nucleases impact biofilm formation in the clinical isolate UAMS-1. Under certainin vitroconditions, this impact is negative, with mutation of either or both of the nuclease genes (nuc1andnuc2) resulting in an enhanced capacity to form a biofilm. However, this effect was not apparentin vivoin a murine model of catheter-associated biofilm formation. Rather, mutation of either or both nuclease genes appeared to limit biofilm formation to a degree that could be correlated with increased susceptibility to daptomycin.

scholarly journals The Impacts of msaABCR on sarA-Associated Phenotypes Are Different in Divergent Clinical Isolates of Staphylococcus aureus

2019 ◽  
Vol 88 (2) ◽  
Author(s):  
Joseph S. Rom ◽  
Aura M. Ramirez ◽  
Karen E. Beenken ◽  
Gyan S. Sahukhal ◽  
Mohamed O. Elasri ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Clinical Isolates ◽  
Protease Production ◽  
Relative Impact ◽  
Extracellular Proteases ◽  
Content Type ◽  
The Impact

ABSTRACT The staphylococcal accessory regulator (sarA) plays an important role in Staphylococcus aureus infections, including osteomyelitis, and the msaABCR operon has been implicated as an important factor in modulating expression of sarA. Thus, we investigated the contribution of msaABCR to sarA-associated phenotypes in the S. aureus clinical isolates LAC and UAMS-1. Mutation of msaABCR resulted in reduced production of SarA and a reduced capacity to form a biofilm in both strains. Biofilm formation was enhanced in a LAC msa mutant by restoring the production of SarA, but this was not true in a UAMS-1 msa mutant. Similarly, extracellular protease production was increased in a LAC msa mutant but not a UAMS-1 msa mutant. This difference was reflected in the accumulation and distribution of secreted virulence factors and in the impact of extracellular proteases on biofilm formation in a LAC msa mutant. Most importantly, it was reflected in the relative impact of mutating msa as assessed in a murine osteomyelitis model, which had a significant impact in LAC but not in UAMS-1. In contrast, mutation of sarA had a greater impact on all of these in vitro and in vivo phenotypes than mutation of msaABCR, and it did so in both LAC and UAMS-1. These results suggest that, at least in osteomyelitis, it would be therapeutically preferable to target sarA rather than msaABCR to achieve the desired clinical result, particularly in the context of divergent clinical isolates of S. aureus.

scholarly journals Regulatory Mutations Impacting Antibiotic Susceptibility in an Established Staphylococcus aureus Biofilm

2016 ◽  
Vol 60 (3) ◽  
pp. 1826-1829 ◽  
Author(s):  
Danielle N. Atwood ◽  
Karen E. Beenken ◽  
Tamara L. Lantz ◽  
Daniel G. Meeker ◽  
William B. Lynn ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Susceptibility ◽  
Biofilm Formation ◽  
Content Type ◽  
Regulatory Mutations ◽  
Regulatory Loci ◽  
Functionally Diverse ◽  
The Impact

We previously determined the extent to which mutations of differentStaphylococcus aureusregulatory loci impact biofilm formation as assessed underin vitroconditions. Here we extend these studies to determine the extent to which those regulatory loci that had the greatest effect on biofilm formation also impact antibiotic susceptibility. The experiments were done underin vitroandin vivoconditions using two clinical isolates ofS. aureus(LAC and UAMS-1) and two functionally diverse antibiotics (daptomycin and ceftaroline). Mutation of the staphylococcal accessory regulator (sarA) orsigBwas found to significantly increase susceptibilities to both antibiotics and in both strains in a manner that could not be explained by changes in the MICs. The impact of a mutation insarAwas comparable to that of a mutation insigBand greater than the impact observed with any other mutant. These results suggest that therapeutic strategies targetingsarAand/orsigBhave the greatest potential to facilitate the ability to overcome the intrinsic antibiotic resistance that definesS. aureusbiofilm-associated infections.

scholarly journals Exogenous Alginate Protects Staphylococcus aureus from Killing by Pseudomonas aeruginosa

2019 ◽  
Vol 202 (8) ◽  
Author(s):  
Courtney E. Price ◽  
Dustin G. Brown ◽  
Dominique H. Limoli ◽  
Vanessa V. Phelan ◽  
George A. O’Toole
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Physical Space ◽  
Late Time ◽  
Protective Effects ◽  
Content Type ◽  
Alginate Production ◽  
The Impact

ABSTRACT Cystic fibrosis (CF) patients chronically infected with both Pseudomonas aeruginosa and Staphylococcus aureus have worse health outcomes than patients who are monoinfected with either P. aeruginosa or S. aureus. We showed previously that mucoid strains of P. aeruginosa can coexist with S. aureus in vitro due to the transcriptional downregulation of several toxic exoproducts typically produced by P. aeruginosa, including siderophores, rhamnolipids, and HQNO (2-heptyl-4-hydroxyquinoline N-oxide). Here, we demonstrate that exogenous alginate protects S. aureus from P. aeruginosa in both planktonic and biofilm coculture models under a variety of nutritional conditions. S. aureus protection in the presence of exogenous alginate is due to the transcriptional downregulation of pvdA, a gene required for the production of the iron-scavenging siderophore pyoverdine as well as the downregulation of the PQS (Pseudomonas quinolone signal) (2-heptyl-3,4-dihydroxyquinoline) quorum sensing system. The impact of exogenous alginate is independent of endogenous alginate production. We further demonstrate that coculture of mucoid P. aeruginosa with nonmucoid P. aeruginosa strains can mitigate the killing of S. aureus by the nonmucoid strain of P. aeruginosa, indicating that the mechanism that we describe here may function in vivo in the context of mixed infections. Finally, we investigated a panel of mucoid clinical isolates that retain the ability to kill S. aureus at late time points and show that each strain has a unique expression profile, indicating that mucoid isolates can overcome the S. aureus-protective effects of mucoidy in a strain-specific manner. IMPORTANCE CF patients are chronically infected by polymicrobial communities. The two dominant bacterial pathogens that infect the lungs of CF patients are P. aeruginosa and S. aureus, with ∼30% of patients coinfected by both species. Such coinfected individuals have worse outcomes than monoinfected patients, and both species persist within the same physical space. A variety of host and environmental factors have been demonstrated to promote P. aeruginosa-S. aureus coexistence, despite evidence that P. aeruginosa kills S. aureus when these organisms are cocultured in vitro. Thus, a better understanding of P. aeruginosa-S. aureus interactions, particularly mechanisms by which these microorganisms are able to coexist in proximal physical space, will lead to better-informed treatments for chronic polymicrobial infections.

scholarly journals Evaluation of Antibiotics Active against Methicillin-Resistant Staphylococcus aureus Based on Activity in an Established Biofilm

2016 ◽  
Vol 60 (10) ◽  
pp. 5688-5694 ◽  
Author(s):  
Daniel G. Meeker ◽  
Karen E. Beenken ◽  
Weston B. Mills ◽  
Allister J. Loughran ◽  
Horace J. Spencer ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Limit Of Detection ◽  
Relative Activity ◽  
Methicillin Resistant ◽  
Content Type ◽  
Comparable Activity ◽  
Antibiotic Delivery

ABSTRACTWe usedin vitroandin vivomodels of catheter-associated biofilm formation to compare the relative activity of antibiotics effective against methicillin-resistantStaphylococcus aureus(MRSA) in the specific context of an established biofilm. The results demonstrated that, underin vitroconditions, daptomycin and ceftaroline exhibited comparable activity relative to each other and greater activity than vancomycin, telavancin, oritavancin, dalbavancin, or tigecycline. This was true when assessed using established biofilms formed by the USA300 methicillin-resistant strain LAC and the USA200 methicillin-sensitive strain UAMS-1. Oxacillin exhibited greater activity against UAMS-1 than LAC, as would be expected, since LAC is an MRSA strain. However, the activity of oxacillin was less than that of daptomycin and ceftaroline even against UAMS-1. Among the lipoglycopeptides, telavancin exhibited the greatest overall activity. Specifically, telavancin exhibited greater activity than oritavancin or dalbavancin when tested against biofilms formed by LAC and was the only lipoglycopeptide capable of reducing the number of viable bacteria below the limit of detection. With biofilms formed by UAMS-1, telavancin and dalbavancin exhibited comparable activity relative to each other and greater activity than oritavancin. Importantly, ceftaroline was the only antibiotic that exhibited greater activity than vancomycin when testedin vivoin a murine model of catheter-associated biofilm formation. These results emphasize the need to consider antibiotics other than vancomycin, most notably, ceftaroline, for the treatment of biofilm-associatedS. aureusinfections, including by the matrix-based antibiotic delivery methods often employed for local antibiotic delivery in the treatment of these infections.

scholarly journals Tissue Plasminogen Activator Coating on Implant Surfaces Reduces Staphylococcus aureus Biofilm Formation

2015 ◽  
Vol 82 (1) ◽  
pp. 394-401 ◽  
Author(s):  
Jakub Kwiecinski ◽  
Manli Na ◽  
Anders Jarneborn ◽  
Gunnar Jacobsson ◽  
Marijke Peetermans ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Medical Devices ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Content Type ◽  
Tissue Plasminogen

ABSTRACTStaphylococcus aureusbiofilm infections of indwelling medical devices are a major medical challenge because of their high prevalence and antibiotic resistance. As fibrin plays an important role inS. aureusbiofilm formation, we hypothesize that coating of the implant surface with fibrinolytic agents can be used as a new method of antibiofilm prophylaxis. The effect of tissue plasminogen activator (tPA) coating onS. aureusbiofilm formation was tested within vitromicroplate biofilm assays and anin vivomouse model of biofilm infection. tPA coating efficiently inhibited biofilm formation by variousS. aureusstrains. The effect was dependent on plasminogen activation by tPA, leading to subsequent local fibrin cleavage. A tPA coating on implant surfaces prevented both early adhesion and later biomass accumulation. Furthermore, tPA coating increased the susceptibility of biofilm infections to antibiotics.In vivo, significantly fewer bacteria were detected on the surfaces of implants coated with tPA than on control implants from mice treated with cloxacillin. Fibrinolytic coatings (e.g., with tPA) reduceS. aureusbiofilm formation bothin vitroandin vivo, suggesting a novel way to prevent bacterial biofilm infections of indwelling medical devices.

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

2014 ◽  
Vol 58 (12) ◽  
pp. 7606-7610 ◽  
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.

scholarly journals Three Novel Candidate Probiotic Strains with Prophylactic Properties in a Murine Model of Cow's Milk Allergy

2016 ◽  
Vol 82 (6) ◽  
pp. 1722-1733 ◽  
Author(s):  
Elodie Neau ◽  
Johanne Delannoy ◽  
Candice Marion ◽  
Charles-Henry Cottart ◽  
Chantal Labellie ◽  
...  
Keyword(s):  
Murine Model ◽  
Food Allergies ◽  
T Helper ◽  
Murine Splenocytes ◽  
Content Type ◽  
Cellular Models ◽  
Probiotic Strains ◽  
The Impact

ABSTRACTFood allergies can have significant effects on morbidity and on quality of life. Therefore, the development of efficient approaches to reduce the risk of developing food allergies is of considerable interest. The aim of this study was to identify and select probiotic strains with preventive properties against allergies using a combination ofin vitroandin vivoapproaches. To that end, 31 strains of bifidobacteria and lactic acid bacteria were screened for their immunomodulatory properties in two cellular models, namely, human peripheral blood mononuclear cells (PBMCs) and T helper 2 (Th2)-skewed murine splenocytes. Six strains inducing a high interleukin-10 (IL-10)/IL-12p70 ratio and a low secretion of IL-4 on the two cellular models were selected, and their protective impact was testedin vivoin a murine model of food allergy to β-lactoglobulin. Three strains showed a protective impact on sensitization, with a decrease in allergen-specific IgE, and on allergy, with a decrease in mast cell degranulation. Analysis of the impact of these three strains on the T helper balance revealed different mechanisms of action. TheLactobacillus salivariusLA307 strain proved to block Th1 and Th2 responses, while theBifidobacterium longumsubsp.infantisLA308 strain induced a pro-Th1 profile and theLactobacillus rhamnosusLA305 strain induced pro-Th1 and regulatory responses. These results demonstrate that a combination ofin vitroandin vivoscreening is effective in probiotic strain selection and allowed identification of three novel probiotic strains that are active against sensitization in mice.

scholarly journals Impact of sarA on Daptomycin Susceptibility of Staphylococcus aureus Biofilms In Vivo

2009 ◽  
Vol 53 (10) ◽  
pp. 4096-4102 ◽  
Author(s):  
Elizabeth C. Weiss ◽  
Agnieszka Zielinska ◽  
Karen E. Beenken ◽  
Horace J. Spencer ◽  
Sonja J. Daily ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Murine Model ◽  
Biofilm Formation ◽  
Parent Strain ◽  
Skin Lesions ◽  
The Other ◽  
Clonal Lineage ◽  
Experimental Group ◽  
Increased Susceptibility

ABSTRACT We used a murine model of catheter-associated biofilm formation to determine whether the mutation of the staphylococcal accessory regulator (sarA) has an impact on the susceptibility of established Staphylococcus aureus biofilms to treatment with daptomycin in vivo. The experiments were done with two clinical isolates, one of which (UAMS-1) was obtained from the bone of a patient suffering from osteomyelitis, while the other (UAMS-1625) is an isolate of the USA300 clonal lineage of community-acquired methicillin (meticillin)-resistant S. aureus. UAMS-1625 had a reduced capacity to form a biofilm in vivo compared to that of UAMS-1 (P = 0.0015), but in both cases the mutation of sarA limited biofilm formation compared to that of the corresponding parent strain (P ≤ 0.001). The mutation of sarA did not affect the daptomycin MIC for either strain, but it did result in increased susceptibility in vivo in the context of an established biofilm. Specifically, daptomycin treatment resulted in the clearance of detectable bacteria from <10% of the catheters colonized with the parent strains, while treatment with an equivalent daptomycin concentration resulted in the clearance of 46.4% of the catheters colonized with the UAMS-1 sarA mutant and 69.1% of the catheters colonized with the UAMS-1625 sarA mutant. In the absence of daptomycin treatment, mice with catheters colonized with the UAMS-1625 parent strain also developed skin lesions in the region adjacent to the implanted catheter. No such lesions were observed in any other experimental group, including untreated mice containing catheters colonized with the UAMS-1625 sarA mutant.

scholarly journals Hyaluronan Modulation Impacts Staphylococcus aureus Biofilm Infection

2016 ◽  
Vol 84 (6) ◽  
pp. 1917-1929 ◽  
Author(s):  
Carolyn B. Ibberson ◽  
Corey P. Parlet ◽  
Jakub Kwiecinski ◽  
Heidi A. Crosby ◽  
David K. Meyerholz ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Infection Model ◽  
Wild Type ◽  
Content Type ◽  
Joint Infections ◽  
The Impact ◽  
Biofilm Infection ◽  
Biofilm Matrix

Staphylococcus aureusis a leading cause of chronic biofilm infections. Hyaluronic acid (HA) is a large glycosaminoglycan abundant in mammalian tissues that has been shown to enhance biofilm formation in multiple Gram-positive pathogens. We observed that HA accumulated in anS. aureusbiofilm infection using a murine implant-associated infection model and that HA levels increased in a mutant strain lacking hyaluronidase (HysA).S. aureussecretes HysA in order to cleave HA during infection. Throughin vitrobiofilm studies with HA, thehysAmutant was found to accumulate increased biofilm biomass compared to the wild type, and confocal microscopy showed that HA is incorporated into the biofilm matrix. Exogenous addition of purified HysA enzyme dispersed HA-containing biofilms, while catalytically inactive enzyme had no impact. Additionally, induction ofhysAexpression prevented biofilm formation and also dispersed an established biofilm in the presence of HA. These observations were corroborated in the implant model, where there was decreased dissemination from anhysAmutant biofilm infection compared to theS. aureuswild type. Histopathology demonstrated that infection with anhysAmutant caused significantly reduced distribution of tissue inflammation compared to wild-type infection. To extend these studies, the impact of HA andS. aureusHysA on biofilm-like aggregates found in joint infections was examined. We found that HA contributes to the formation of synovial fluid aggregates, and HysA can disrupt aggregate formation. Taken together, these studies demonstrate that HA is a relevant component of theS. aureusbiofilm matrix and HysA is important for dissemination from a biofilm infection.

scholarly journals A Human Biofilm-Disrupting Monoclonal Antibody Potentiates Antibiotic Efficacy in Rodent Models of both Staphylococcus aureus and Acinetobacter baumannii Infections

2017 ◽  
Vol 61 (10) ◽  
Author(s):  
Yan Q. Xiong ◽  
Angeles Estellés ◽  
L. Li ◽  
W. Abdelhady ◽  
R. Gonzales ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Monoclonal Antibody ◽  
Acinetobacter Baumannii ◽  
Bacterial Infections ◽  
Bacterial Species ◽  
Human Monoclonal Antibody ◽  
Extracellular Dna ◽  
Content Type

ABSTRACT Many serious bacterial infections are antibiotic refractory due to biofilm formation. A key structural component of biofilm is extracellular DNA, which is stabilized by bacterial proteins, including those from the DNABII family. TRL1068 is a high-affinity human monoclonal antibody against a DNABII epitope conserved across both Gram-positive and Gram-negative bacterial species. In the present study, the efficacy of TRL1068 for the disruption of biofilm was demonstrated in vitro in the absence of antibiotics by scanning electron microscopy. The in vivo efficacy of this antibody was investigated in a well-characterized catheter-induced aortic valve infective endocarditis model in rats infected with a methicillin-resistant Staphylococcus aureus (MRSA) strain with the ability to form thick biofilms, obtained from the blood of a patient with persistent clinical infection. Animals were treated with vancomycin alone or in combination with TRL1068. MRSA burdens in cardiac vegetations and within intracardiac catheters, kidneys, spleen, and liver showed significant reductions in the combination arm versus vancomycin alone (P < 0.001). A trend toward mortality reduction was also observed (P = 0.09). In parallel, the in vivo efficacy of TRL1068 against a multidrug-resistant clinical Acinetobacter baumannii isolate was explored by using an established mouse model of skin and soft tissue catheter-related biofilm infection. Catheter segments infected with A. baumannii were implanted subcutaneously into mice; animals were treated with imipenem alone or in combination with TRL1068. The combination showed a significant reduction of catheter-adherent bacteria versus the antibiotic alone (P < 0.001). TRL1068 shows excellent promise as an adjunct to standard-of-care antibiotics for a broad range of difficult-to-treat bacterial infections.

Sign in / Sign up

Export Citation Format

Share Document