scholarly journals Genetic Evidence for an Alternative Citrate-Dependent Biofilm Formation Pathway in Staphylococcus aureus That Is Dependent on Fibronectin Binding Proteins and the GraRS Two-Component Regulatory System

2008 ◽  
Vol 76 (6) ◽  
pp. 2469-2477 ◽  
Author(s):  
Robert M. Q. Shanks ◽  
Michael A. Meehl ◽  
Kimberly M. Brothers ◽  
Raquel M. Martinez ◽  
Niles P. Donegan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Binding Proteins ◽  
Regulatory System ◽  
Tca Cycle ◽  
Formation Pathway ◽  
Two Component ◽  
Fibronectin Binding ◽  
Tca Cycle Intermediates

ABSTRACT We reported previously that low concentrations of sodium citrate strongly promote biofilm formation by Staphylococcus aureus laboratory strains and clinical isolates. Here, we show that citrate promotes biofilm formation via stimulating both cell-to-surface and cell-to-cell interactions. Citrate-stimulated biofilm formation is independent of the ica locus, and in fact, citrate represses polysaccharide adhesin production. We show that fibronectin binding proteins FnbA and FnbB and the global regulator SarA, which positively regulates fnbA and fnbB gene expression, are required for citrate's positive effects on biofilm formation, and citrate also stimulates fnbA and fnbB gene expression. Biofilm formation is also stimulated by several other tricarboxylic acid (TCA) cycle intermediates in an FnbA-dependent fashion. While aconitase contributes to biofilm formation in the absence of TCA cycle intermediates, it is not required for biofilm stimulation by these compounds. Furthermore, the GraRS two-component regulator and the GraRS-regulated efflux pump VraFG, identified for their roles in intermediate vancomycin resistance, are required for citrate-stimulated cell-to-cell interactions, but the GraRS regulatory system does not impact the expression of the fnbA and fnbB genes. Our data suggest that distinct genetic factors are required for the early steps in citrate-stimulated biofilm formation. Given the role of FnbA/FnbB and SarA in virulence in vivo and the lack of a role for ica-mediated biofilm formation in S. aureus catheter models of infection, we propose that the citrate-stimulated biofilm formation pathway may represent a clinically relevant pathway for the formation of these bacterial communities on medical implants.

scholarly journals A Novel Staphylococcus aureus Biofilm Phenotype Mediated by the Fibronectin-Binding Proteins, FnBPA and FnBPB

2008 ◽  
Vol 190 (11) ◽  
pp. 3835-3850 ◽  
Author(s):  
Eoghan O'Neill ◽  
Clarissa Pozzi ◽  
Patrick Houston ◽  
Hilary Humphreys ◽  
D. Ashley Robinson ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Binding Proteins ◽  
Clinical Problem ◽  
Growth Conditions ◽  
Surface Proteins ◽  
Fibrinogen Binding ◽  
Fibronectin Binding ◽  
Mrsa Strains ◽  
Biofilm Development

ABSTRACT Device-associated infections involving biofilm remain a persistent clinical problem. We recently reported that four methicillin-resistant Staphylococcus aureus (MRSA) strains formed biofilm independently of the icaADBC-encoded exopolysaccharide. Here, we report that MRSA biofilm development was promoted under mildly acidic growth conditions triggered by the addition of glucose to the growth medium. Loss of sortase, which anchors LPXTG-containing proteins to peptidoglycan, reduced the MRSA biofilm phenotype. Furthermore introduction of mutations in fnbA and fnbB, which encode the LPXTG-anchored multifunctional fibrinogen and fibronectin-binding proteins, FnBPA and FnBPB, reduced biofilm formation by several MRSA strains. However, these mutations had no effect on biofilm formation by methicillin-sensitive S. aureus strains. FnBP-promoted biofilm occurred at the level of intercellular accumulation and not primary attachment. Mutation of fnbA or fnbB alone did not substantially affect biofilm, and expression of either gene alone from a complementing plasmid in fnbA fnbB mutants restored biofilm formation. FnBP-promoted biofilm was dependent on the integrity of SarA but not through effects on fnbA or fnbB transcription. Using plasmid constructs lacking regions of FnBPA to complement an fnbAB mutant revealed that the A domain alone and not the domain required for fibronectin binding could promote biofilm. Additionally, an A-domain N304A substitution that abolished fibrinogen binding did not affect biofilm. These data identify a novel S. aureus biofilm phenotype promoted by FnBPA and FnBPB which is apparently independent of the known ligand-binding activities of these multifunctional surface proteins.

scholarly journals The Staphylococcus aureus LytSR Two-Component Regulatory System Affects Biofilm Formation

2009 ◽  
Vol 191 (15) ◽  
pp. 4767-4775 ◽  
Author(s):  
Batu K. Sharma-Kuinkel ◽  
Ethan E. Mann ◽  
Jong-Sam Ahn ◽  
Lisa J. Kuechenmeister ◽  
Paul M. Dunman ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Regulatory System ◽  
Hydrolase Activity ◽  
Antibiotic Tolerance ◽  
Gene Products ◽  
Knockout Mutant ◽  
Two Component ◽  
Murein Hydrolase ◽  
Biofilm Development

ABSTRACT Studies of the Staphylococcus aureus LytSR two-component regulatory system have led to the identification of the cid and lrg operons, which affect murein hydrolase activity, stationary-phase survival, antibiotic tolerance, and biofilm formation. The cid gene products enhance murein hydrolase activity and antibiotic tolerance whereas the lrg gene products inhibit these processes in a manner believed to be analogous to bacteriophage-encoded holins and antiholins, respectively. Importantly, these operons have been shown to play significant roles in biofilm development by controlling the release of genomic DNA, which then becomes an important structural component of the biofilm matrix. To determine the role of LytSR in biofilm development, a lytS knockout mutant was generated from a clinical S. aureus isolate (UAMS-1) and the effects on gene expression and biofilm formation were examined. As observed in laboratory isolates, LytSR was found to be required for lrgAB expression. Furthermore, the lytS mutant formed a more adherent biofilm than the wild-type and complemented strains. Consistent with previous findings, the increased adherence of the mutant was attributed to the increased prevalence of matrix-associated eDNA. Transcription profiling studies indicated that the lrgAB operon is the primary target of LytSR-mediated regulation but that this regulatory system also impacts expression of a wide variety of genes involved in basic metabolism. Overall, the results of these studies demonstrate that the LytSR two-component regulatory system plays an important role in S. aureus biofilm development, likely as a result of its direct influence on lrgAB expression.

scholarly journals Norlichexanthone Reduces Virulence Gene Expression and Biofilm Formation in Staphylococcus aureus

PLoS ONE ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. e0168305 ◽  
Author(s):  
Mara Baldry ◽  
Anita Nielsen ◽  
Martin S. Bojer ◽  
Yu Zhao ◽  
Cathrine Friberg ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Virulence Gene ◽  
Virulence Gene Expression

scholarly journals Molecular Investigation of Fibronectin-Binding Protein Genes and Capacity of Biofilm Production in Staphylococcus Aureus Isolated From Clinical Samples

2021 ◽  
Author(s):  
Hossein Jafari Soghondicolaei ◽  
Mohammad Ahanjan ◽  
Mehrdad Gholami ◽  
Bahman Mirzaei ◽  
Hamid Reza Goli
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Colorimetric Assay ◽  
Binding Protein ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Biofilm Production ◽  
Fibronectin Binding Protein ◽  
Fibronectin Binding

Abstract Biofilm production increases Staphylococcus aureus resistance to antibiotics and also host defense mechanisms. The current study aims to evaluate the biofilm formation by S. aureus and to determine the prevalence of fibronectin-binding protein genes, also its correlation with drug resistance. In this study, 100 clinical isolates of S. aureus were collected. The antibiotic susceptibility pattern of the isolates was evaluated by the disk agar diffusion method. The ability of biofilm formation in the studied isolates was also determined by microplate colorimetric assay. Then, all isolates were screened by polymerase chain reaction for the fnbA and fnbB genes. Out of 100 clinical isolates of S. aureus, the highest and lowest antibiotic resistance rates were against penicillin (94%) and vancomycin (6%). Thirty-two cases were found to be multi-drug resistant (MDR) among the all strains. The ability of biofilm production was observed in 89% of the isolates. The PCR results showed that the prevalence of fnbA and fnbB genes were 91% and 17%, respectively. Moreover, 100% and 21.8% of the MDR strains harbored the fnbA and fnbB genes respectively. The ability to form biofilm in MDR isolates of S. aureus is more than non-MDR isolates, especially fnbA positive ones. As the bacteria in the biofilm are difficult to kill by antibiotics, attention to the removal or control of the biofilm production seems to be necessary.

scholarly journals Novel Inhibitors of Staphylococcus aureus Virulence Gene Expression and Biofilm Formation

PLoS ONE ◽  
2012 ◽  
Vol 7 (10) ◽  
pp. e47255 ◽  
Author(s):  
Yibao Ma ◽  
Yuanxi Xu ◽  
Bryan D. Yestrepsky ◽  
Roderick J. Sorenson ◽  
Meng Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Virulence Gene ◽  
Virulence Gene Expression

scholarly journals FlhF and Its GTPase Activity Are Required for Distinct Processes in Flagellar Gene Regulation and Biosynthesis in Campylobacter jejuni

2009 ◽  
Vol 191 (21) ◽  
pp. 6602-6611 ◽  
Author(s):  
Murat Balaban ◽  
Stephanie N. Joslin ◽  
David R. Hendrixson
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Campylobacter Jejuni ◽  
Regulatory System ◽  
Flagellar Gene ◽  
Gtpase Activity ◽  
Gtp Hydrolysis ◽  
Genetic Analyses ◽  
Flagellar Biosynthesis ◽  
Two Component

ABSTRACT FlhF proteins are putative GTPases that are often necessary for one or more steps in flagellar organelle development in polarly flagellated bacteria. In Campylobacter jejuni, FlhF is required for σ54-dependent flagellar gene expression and flagellar biosynthesis, but how FlhF influences these processes is unknown. Furthermore, the GTPase activity of any FlhF protein and the requirement of this speculated activity for steps in flagellar biosynthesis remain uncharacterized. We show here that C. jejuni FlhF hydrolyzes GTP, indicating that these proteins are GTPases. C. jejuni mutants producing FlhF proteins with reduced GTPase activity were not severely defective for σ54-dependent flagellar gene expression, unlike a mutant lacking FlhF. Instead, these mutants had a propensity to lack flagella or produce flagella in improper numbers or at nonpolar locations, indicating that GTP hydrolysis by FlhF is required for proper flagellar biosynthesis. Additional studies focused on elucidating a possible role for FlhF in σ54-dependent flagellar gene expression were conducted. These studies revealed that FlhF does not influence production of or signaling between the flagellar export apparatus and the FlgSR two-component regulatory system to activate σ54. Instead, our data suggest that FlhF functions in an independent pathway that converges with or works downstream of the flagellar export apparatus-FlgSR pathway to influence σ54-dependent gene expression. This study provides corroborative biochemical and genetic analyses suggesting that different activities of the C. jejuni FlhF GTPase are required for distinct steps in flagellar gene expression and biosynthesis. Our findings are likely applicable to many polarly flagellated bacteria that utilize FlhF in flagellar biosynthesis processes.

An Alanine-Rich Peptide Attenuates Quorum Sensing-Regulated Virulence and Biofilm Formation in Staphylococcus aureus

2019 ◽  
Vol 102 (4) ◽  
pp. 1228-1234 ◽  
Author(s):  
Raid Al Akeel ◽  
Ayesha Mateen ◽  
Rabbani Syed
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Bacterial Attachment ◽  
The Body ◽  
Dependent Manner ◽  
Virulence Determinants ◽  
Microarray Gene Expression ◽  
Concentration Dependent Manner

Abstract Background: Alanine-rich proteins/peptides (ARP), with bioactivity of up to 20 amino acid residues, can be observed by the body easily during gastrointestinal digestion. Objective: Populus trichocarpa extract’s capability to attenuate quorum sensing-regulated virulence and biofilm formation in Staphylococcus aureus is described. Methods: PT13, an ARP obtained from P. trichocarpa, was tested for its activity against S. aureus using the broth microdilution test; a crystal-violet biofilm assay was performed under a scanning electron microscope. The production of various virulence factors was estimated with PT13 treatment. Microarray gene expression profiling of PT13-treated S. aureus was conducted and compared with an untreated control. Exopolysaccharides (EPS) was estimated to observe the PT13 inhibition activity. Results: PT13 was antimicrobial toward S. aureus at different concentrations and showed a similar growth rate in the presence and absence of PT13 at concentrations ≤8 μg/mL. Biofilm production was interrupted even at low concentrations, and biofilm-related genes were down-regulated when exposed to PT13. The genes encoding cell adhesion and bacterial attachment protein were the major genes suppressed by PT13. In addition, hemolysins, clumping activity, and EPS production of S. aureus decreased after treatment in a concentration-dependent manner. Conclusions: A long-chain PT13 with effective actions that, even at low concentration levels, not only regulated the gene expression in the producer organism but also blocked the virulence gene expression in this Gram-positive human pathogen is described. Highlights: We identified a PT13 as a potential antivirulence agent that regulated production of bacterial virulence determinants (e.g., toxins, enzymes and biofilm), downwards and it may be a promising anti-virulence agent to be further developed as an anti-infective agent.

Sign in / Sign up

Export Citation Format

Share Document