scholarly journals Influence of sub-inhibitory concentrations of antimicrobials on micrococcal nuclease and biofilm formation in Staphylococcus aureus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Colin W. K. Rosman ◽  
Henny C. van der Mei ◽  
Jelmer Sjollema
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Extracellular Dna ◽  
Micrococcal Nuclease ◽  
Host Immune System ◽  
Total Biomass ◽  
Major Contributor ◽  
The Impact

AbstractA major contributor to biomaterial associated infection (BAI) is Staphylococcus aureus. This pathogen produces a protective biofilm, making eradication difficult. Biofilms are composed of bacteria encapsulated in a matrix of extracellular polymeric substances (EPS) comprising polysaccharides, proteins and extracellular DNA (eDNA). S. aureus also produces micrococcal nuclease (MN), an endonuclease which contributes to biofilm composition and dispersion, mainly expressed by nuc1. MN expression can be modulated by sub-minimum inhibitory concentrations of antimicrobials. We investigated the relation between the biofilm and MN expression and the impact of the application of antimicrobial pressure on this relation. Planktonic and biofilm cultures of three S. aureus strains, including a nuc1 deficient strain, were cultured under antimicrobial pressure. Results do not confirm earlier findings that MN directly influences total biomass of the biofilm but indicated that nuc1 deletion stimulates the polysaccharide production per CFU in the biofilm in in vitro biofilms. Though antimicrobial pressure of certain antibiotics resulted in significantly increased quantities of polysaccharides per CFU, this did not coincide with significantly reduced MN activity. Erythromycin and resveratrol significantly reduced MN production per CFU but did not affect total biomass or biomass/CFU. Reduction of MN production may assist in the eradication of biofilms by the host immune system in clinical situations.

scholarly journals Influence of sub-inhibitory concentrations of antimicrobials on micrococcal nuclease and biofilm formation in Staphylococcus aureus

2020 ◽  
Author(s):  
Jelmer Sjollema ◽  
Henny van der Mei ◽  
Colin Rosman
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Extracellular Dna ◽  
Micrococcal Nuclease ◽  
Major Contributor ◽  
Polysaccharide Production ◽  
Minimum Inhibitory Concentrations ◽  
The Impact

Abstract A major contributor to biomaterial associated infection (BAI) is Staphylococcus aureus. This pathogen produces a protective biofilm, making eradication difficult. Biofilms are composed of bacteria encapsulated in a matrix of extracellular polymeric substances (EPS) comprising polysaccharides, proteins and extracellular DNA (eDNA). S. aureus also produces micrococcal nuclease (MN), an endonuclease which contributes to biofilm composition and dispersion, mainly expressed by nuc1. MN expression can be modulated by sub-minimum inhibitory concentrations of antimicrobials. We investigated the relation between the biofilm and MN expression and the impact of the application of antimicrobial pressure on this relation. Planktonic and biofilm cultures of three S. aureus strains, including a nuc1 deficient strain, were cultured under antimicrobial pressure. Results indicated that nuc1 deletion stimulates the polysaccharide production per CFU in the biofilm in in vitro biofilms. Also antimicrobial pressure of ciproflocacin, doxycycline and erythromycin resulted in significantly increased quantities of polysaccharides per CFU, but this did only coincide with significantly reduced MN activity in erythromycin. Resveratrol significantly reduced MN production per CFU but did not affect polysaccharides production. In conclusion, various antimicrobials impact the balance of eDNA, polysaccharides and MN production, all in a different way.

scholarly journals Micrococcal Nuclease stimulates Staphylococcus aureus Biofilm Formation in a Murine Implant Infection Model

2022 ◽  
Vol 11 ◽  
Author(s):  
Abigail M. Forson ◽  
Colin W. K. Rosman ◽  
Theo G. van Kooten ◽  
Henny C. van der Mei ◽  
Jelmer Sjollema
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Polyvinylidene Fluoride ◽  
Histological Analysis ◽  
Ex Vivo ◽  
Extracellular Dna ◽  
Neutrophil Extracellular Trap ◽  
Micrococcal Nuclease ◽  
Infection Model ◽  
The Impact

Advancements in contemporary medicine have led to an increasing life expectancy which has broadened the application of biomaterial implants. As each implant procedure has an innate risk of infection, the number of biomaterial-associated infections keeps rising. Staphylococcus aureus causes 34% of such infections and is known as a potent biofilm producer. By secreting micrococcal nuclease S. aureus is able to escape neutrophil extracellular traps by cleaving their DNA-backbone. Also, micrococcal nuclease potentially limits biofilm growth and adhesion by cleaving extracellular DNA, an important constituent of biofilms. This study aimed to evaluate the impact of micrococcal nuclease on infection persistence and biofilm formation in a murine biomaterial-associated infection-model with polyvinylidene-fluoride mesh implants inoculated with bioluminescent S. aureus or its isogenic micrococcal nuclease deficient mutant. Supported by results based on in-vivo bioluminescence imaging, ex-vivo colony forming unit counts, and histological analysis it was found that production of micrococcal nuclease enables S. aureus bacteria to evade the immune response around an implant resulting in a persistent infection. As a novel finding, histological analysis provided clear indications that the production of micrococcal nuclease stimulates S. aureus to form biofilms, the presence of which extended neutrophil extracellular trap formation up to 13 days after mesh implantation. Since micrococcal nuclease production appeared vital for the persistence of S. aureus biomaterial-associated infection, targeting its production could be a novel strategy in preventing biomaterial-associated infection.

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 Pros and Cons of Cystic Fibrosis (CF) Patient Use of Herbal Supplements Containing Pulmonaria officinalis L. Extract: the Evidence from an In Vitro Study on Staphylococcus aureus CF Clinical Isolates

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1151
Author(s):  
Beata Sadowska ◽  
Urszula Wójcik ◽  
Justyna Krzyżanowska-Kowalczyk ◽  
Mariusz Kowalczyk ◽  
Anna Stochmal ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
In Vivo Studies ◽  
Staphylococcal Protein A ◽  
Herbal Supplements ◽  
The Impact

The justification for the use of herbal supplements with Pulmonaria officinalis L. extract (POE) in the case of staphylococcal lung colonization/infections characteristic for cystic fibrosis (CF), was examined in vitro. The impact of POE phenolic-rich fraction on the virulence attributes of CF-associated Staphylococcus aureus (S. aureus) clinical strains has been assessed, including pathogen adhesion, biofilm formation on native and protein-conditioned surfaces (mucin, elastin), mature biofilm eradication, staphylococcal protein A expression, α-toxin release, and S. a. adhesion to A549 cells. Cytotoxicity of the extract to lung epithelial cells was also investigated. It was found that POE has bacteriostatic effects at MIC 1–2 mg/mL, recognized as of limited efficacy, but at MIC/subMICs it targeted virulence not viability. It usually decreased S. aureus adhesion and less frequently inhibited biofilm formation on native and protein-conditioned surfaces. Observed effect seems to be related to significant reduction by POE of sortase A activity. However, in some cases POE favored the creation of biofilm by staphylococci and S. aureus adhesion to the lung epithelium was not limited. On the other side POE caused significant decrease of S. a. α-toxin synthesis and slightly weakened the expression of SpA. When used at supraMICs POE eradicated mature biofilm, but in some cases with unsatisfying outcomes. Promisingly, POE has been recognized as a safe product, with no cytotoxicity up to 4 mg/mL. These results reflect the positive, negative or neutral anti-staphylococcal properties of POE. It seems that POE may be beneficial as a prophylactic, but not as a therapeutic or supportive agent in the area of CF—integrative medicine. However, introduction the official recommendations needs further in vivo studies.

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.

Impact of sarA Mutation on Immune System Evasion and Stress Response in Staphylococcus aureus

2020 ◽  
Vol 29 (3) ◽  
pp. 105-112
Author(s):  
Yomna A. Hagag ◽  
Abdelaziz Elgaml ◽  
Ramadan Hassan ◽  
Hany I. Kenawy
Keyword(s):  
Staphylococcus Aureus ◽  
Immune System ◽  
Biofilm Formation ◽  
Type Strain ◽  
Wild Type Strain ◽  
Human Neutrophils ◽  
Bacterial Survival ◽  
Wild Type ◽  
The Impact

Background: Staphylococcus aureus is a major human pathogen responsible for a large number of infections. In S. aureus, SarA is an important global locus responsible for the regulation of virulence factors, as well as biofilm formation. Objectives: The aim of this work is to clarify the impact of SarA on biofilm formation, immune system evasion, as well as the survival of S. aureus under stress conditions. Methodology: A comparative study between S. aureus wild type strain, sarA mutant and complemented strains was established addressing the biofilm formation, opsonization, phagocytosis, as well as ability of the bacterium to survive in stressful environments including acidic pH, hyperosmotic and oxidative stress. The in vitro experiments were confirmed by challenging of mice via intraperitoneal injection with the wild type strain, sarA mutant and complemented strains. Results: Mutation of sarA diminished significantly biofilm formation. Moreover, this mutation resulted in a slight decrease in the deposition of the most important opsonin in complement-mediated immunity, named C3 on S. aureus cells. However, this mutation was associated with a significant enhancement of bacterial phagocytosis and killing by human neutrophils. Furthermore, this mutation altered bacterial survival in stressful conditions. It is also noteworthy that sarA mutation resulted in a significant higher survival rates during the challenging of mice. Conclusion: SarA plays a role as a key regulator of biofilm formation, which in turn has a great impact on immune system evasion through affecting opsonization and phagocytosis. In addition, SarA improves the ability of S. aureus to survive in stressful conditions.

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 High-Affinity Native Human Antibody Disrupts Biofilm from Staphylococcus aureus Bacteria and Potentiates Antibiotic Efficacy in a Mouse Implant Infection Model

2016 ◽  
Vol 60 (4) ◽  
pp. 2292-2301 ◽  
Author(s):  
Angeles Estellés ◽  
Anne-Kathrin Woischnig ◽  
Keyi Liu ◽  
Robert Stephenson ◽  
Evelene Lomongsod ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Human Monoclonal Antibody ◽  
Integration Host Factor ◽  
Extracellular Dna ◽  
Infection Model ◽  
Antibody Concentration ◽  
Human Antibody

ABSTRACTMany serious bacterial infections are difficult to treat due to biofilm formation, which provides physical protection and induces a sessile phenotype refractory to antibiotic treatment compared to the planktonic state. A key structural component of biofilm is extracellular DNA, which is held in place by secreted bacterial proteins from the DNABII family: integration host factor (IHF) and histone-like (HU) proteins. A native human monoclonal antibody, TRL1068, has been discovered using single B-lymphocyte screening technology. It has low-picomolar affinity against DNABII homologs from important Gram-positive and Gram-negative bacterial pathogens. The disruption of established biofilm was observedin vitroat an antibody concentration of 1.2 μg/ml over 12 h. The effect of TRL1068in vivowas evaluated in a murine tissue cage infection model in which a biofilm is formed by infection with methicillin-resistantStaphylococcus aureus(MRSA; ATCC 43300). Treatment of the established biofilm by combination therapy of TRL1068 (15 mg/kg of body weight, intraperitoneal [i.p.] administration) with daptomycin (50 mg/kg, i.p.) significantly reduced adherent bacterial count compared to that after daptomycin treatment alone, accompanied by significant reduction in planktonic bacterial numbers. The quantification of TRL1068 in sample matrices showed substantial penetration of TRL1068 from serum into the cage interior. TRL1068 is a clinical candidate for combination treatment with standard-of-care antibiotics to overcome the drug-refractory state associated with biofilm formation, with potential utility for a broad spectrum of difficult-to-treat bacterial infections.

Study of the impact of cultivation conditions and peg surface modification on the in vitro biofilm formation of Staphylococcus aureus and Staphylococcus epidermidis in a system analogous to the Calgary biofilm device

2021 ◽  
Vol 70 (5) ◽  
Author(s):  
Adéla Diepoltová ◽  
Klára Konečná ◽  
Ondřej Janďourek ◽  
Petr Nachtigal
Keyword(s):  
Staphylococcus Aureus ◽  
Surface Modification ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Type Species ◽  
Cultivation Conditions ◽  
Content Type ◽  
Link Type ◽  
The Impact

Introduction. Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) are the most common pathogens from the genus Staphylococcus causing biofilm-associated infections. Generally, biofilm-associated infections represent a clinical challenge. Bacteria in biofilms are difficult to eradicate due to their resistance and serve as a reservoir for recurring persistent infections. Gap Statement. A variety of protocols for in vitro drug activity testing against staphylococcal biofilms have been introduced. However, there are often fundamental differences. All these differences in methodical approaches can then be reflected in the form of discrepancies between results. Aim. In this study, we aimed to develop optimal conditions for staphylococcal biofilm formation on pegs. The impact of peg surface modification was also studied. Methodology. The impact of tryptic soy broth alone or supplemented with foetal bovine serum (FBS) or human plasma (HP), together with the impact of the inoculum density of bacterial suspensions and the shaking versus the static mode of cultivation, on total biofilm biomass production in SA and SE reference strains was studied. The surface of pegs was modified with FBS, HP, or poly-l-lysine (PLL). The impact on total biofilm biomass was evaluated using the crystal violet staining method and statistical data analysis. Results. Tryptic soy broth supplemented with HP together with the shaking mode led to crucial potentiation of biofilm formation on pegs in SA strains. The SE strain did not produce biofilm biomass under the same conditions on pegs. Preconditioning of peg surfaces with FBS and HP led to a statistically significant increase in biofilm biomass formation in the SE strain. Conclusion. Optimal cultivation conditions for robust staphylococcal biofilm formation in vitro might differ among different bacterial strains and methodical approaches. The shaking mode and supplementation of cultivation medium with HP was beneficial for biofilm formation on pegs for SA (ATCC 29213) and methicillin-resistant SA (ATCC 43300). Peg conditioning with HP and PLL had no impact on biofilm formation in either of these strains. Peg coating with FBS showed an adverse effect on the biofilm formation of these strains. By contrast, there was a statistically significant increase in biofilm biomass production on pegs coated with FBS and HP for SE (ATCC 35983).

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.

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