sae is essential for expression of the staphylococcal adhesins Eap and Emp

Microbiology ◽  
2005 ◽  
Vol 151 (6) ◽  
pp. 1789-1800 ◽  
Author(s):  
Niamh Harraghy ◽  
Jan Kormanec ◽  
Christiane Wolz ◽  
Dagmar Homerova ◽  
Christiane Goerke ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Extracellular Matrix ◽  
Virulence Factor ◽  
Eukaryotic Cells ◽  
Transcription Start Point ◽  
Chronic Infections ◽  
Transcription Start ◽  
Regulatory Mutants ◽  
Global Regulators ◽  
Glucose Analysis

Eap and Emp are two Staphylococcus aureus adhesins initially described as extracellular matrix binding proteins. Eap has since emerged as being important in adherence to and invasion of eukaryotic cells, as well as being described as an immunomodulator and virulence factor in chronic infections. This paper describes the mapping of the transcription start point of the eap and emp promoters. Moreover, using reporter-gene assays and real-time PCR in defined regulatory mutants, environmental conditions and global regulators affecting expression of eap and emp were investigated. Marked differences were found in expression of eap and emp between strain Newman and the 8325 derivatives SH1000 and 8325-4. Moreover, both genes were repressed in the presence of glucose. Analysis of expression of both genes in various regulatory mutants revealed that sarA and agr were involved in their regulation, but the data suggested that there were additional regulators of both genes. In a sae mutant, expression of both genes was severely repressed. sae expression was also reduced in the presence of glucose, suggesting that repression of eap and emp in glucose-containing medium may, in part, be a consequence of a decrease in expression of sae.

scholarly journals Staphylococcus aureus Develops an Alternative, ica-Independent Biofilm in the Absence of the arlRS Two-Component System

2005 ◽  
Vol 187 (15) ◽  
pp. 5318-5329 ◽  
Author(s):  
Alejandro Toledo-Arana ◽  
Nekane Merino ◽  
Marta Vergara-Irigaray ◽  
Michel Débarbouillé ◽  
José R. Penadés ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Defined Medium ◽  
Chronic Infections ◽  
Negative Regulators ◽  
Global Regulators ◽  
Two Component ◽  
Two Component Systems ◽  
Important Virulence Factor ◽  
Biofilm Development

ABSTRACT The biofilm formation capacity of Staphylococcus aureus clinical isolates is considered an important virulence factor for the establishment of chronic infections. Environmental conditions affect the biofilm formation capacity of S. aureus, indicating the existence of positive and negative regulators of the process. The majority of the screening procedures for identifying genes involved in biofilm development have been focused on genes whose presence is essential for the process. In this report, we have used random transposon mutagenesis and systematic disruption of all S. aureus two-component systems to identify negative regulators of S. aureus biofilm development in a chemically defined medium (Hussain-Hastings-White modified medium [HHWm]). The results of both approaches coincided in that they identified arlRS as a repressor of biofilm development under both steady-state and flow conditions. The arlRS mutant exhibited an increased initial attachment as well as increased accumulation of poly-N-acetylglucosamine (PNAG). However, the biofilm formation of the arlRS mutant was not affected when the icaADBC operon was deleted, indicating that PNAG is not an essential compound of the biofilm matrix produced in HHWm. Disruption of the major autolysin gene, atl, did not produce any effect on the biofilm phenotype of an arlRS mutant. Epistatic experiments with global regulators involved in staphylococcal-biofilm formation indicated that sarA deletion abolished, whereas agr deletion reinforced, the biofilm development promoted by the arlRS mutation.

scholarly journals Staphylococcus aureus Hyaluronidase Is a CodY-Regulated Virulence Factor

2014 ◽  
Vol 82 (10) ◽  
pp. 4253-4264 ◽  
Author(s):  
Carolyn B. Ibberson ◽  
Crystal L. Jones ◽  
Shweta Singh ◽  
Matthew C. Wise ◽  
Mark E. Hart ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Hyaluronic Acid ◽  
Virulence Factor ◽  
Bacterial Infections ◽  
Lung Pathology ◽  
Diverse Range ◽  
Content Type ◽  
Global Regulators ◽  
Protein Levels ◽  
Unit Reduction

ABSTRACTStaphylococcus aureusis a Gram-positive pathogen that causes a diverse range of bacterial infections. InvasiveS. aureusstrains secrete an extensive arsenal of hemolysins, immunomodulators, and exoenzymes to cause disease. Our studies have focused on the secreted enzyme hyaluronidase (HysA), which cleaves the hyaluronic acid polymer at the β-1,4 glycosidic bond. In the study described in this report, we have investigated the regulation and contribution of this enzyme toS. aureuspathogenesis. Using the Nebraska Transposon Mutant Library (NTML), we identified eight insertions that modulate extracellular levels of HysA activity. Insertions in thesigBoperon, as well as in genes encoding the global regulators SarA and CodY, significantly increased HysA protein levels and activity. By altering the availability of branched-chain amino acids, we further demonstrated CodY-dependent repression of HysA activity. Additionally, through mutation of the CodY binding box upstream ofhysA, the repression of HysA production was lost, suggesting that CodY is a direct repressor ofhysAexpression. To determine whether HysA is a virulence factor, a ΔhysAmutant of a community-associated methicillin-resistantS. aureus(CA-MRSA) USA300 strain was constructed and found to be attenuated in a neutropenic, murine model of pulmonary infection. Mice infected with this mutant strain exhibited a 4-log-unit reduction in bacterial burden in their lungs, as well as reduced lung pathology and increased levels of pulmonary hyaluronic acid, compared to mice infected with the wild-type, parent strain. Taken together, these results indicate thatS. aureushyaluronidase is a CodY-regulated virulence factor.

scholarly journals Genotypic and Phenotypic Assessment of Hyaluronidase among Type Strains of a Select Group of Staphylococcal Species

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Mark E. Hart ◽  
Morgan J. Hart ◽  
Anna J. Roop
Keyword(s):  
Staphylococcus Aureus ◽  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
Virulence Factor ◽  
Chromosomal Dna ◽  
Potential Virulence Factor ◽  
Hyaluronidase Activity ◽  
Select Group ◽  
Type Strains ◽  
Spent Media

Hyaluronidases degrade hyaluronic acid, a major polysaccharide of the extracellular matrix of tissues, and are considered important for virulence in a number of Gram-positive and -negative bacteria. The purpose of the present study was to determine the prevalence of hyaluronidase among clinical strains ofStaphylococcus aureusand among otherStaphylococcusspecies. Spent media and chromosomal DNA were assessed for hyaluronidase activity and the absence or presence of a hyaluronidase gene (hysA) by Southern analysis, respectively. AllS. aureusstrains examined exhibited at least one hybridizing band (half of the strains exhibited two or more hybridizing bands) when probed forhysAand all but three of these strains produced hyaluronidase. In contrast, none of the type strains of 19 other species exhibited either hyaluronidase activity or hybridizing bands when probed forhysA. These data support the hypothesis that among members of theStaphylococcusgenus only strains ofS. aureuspossess the enzyme hyaluronidase. This would suggest that hyaluronidase represents yet another potential virulence factor employed byS. aureusto cause disease and may represent a diagnostically important characteristic for distinguishingS. aureusfrom other members of this genus.

scholarly journals Pseudomonas aeruginosa PA14 Enhances the Efficacy of Norfloxacin against Staphylococcus aureus Newman Biofilms

2020 ◽  
Vol 202 (18) ◽  
Author(s):  
Giulia Orazi ◽  
Fabrice Jean-Pierre ◽  
George A. O’Toole
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Respiratory Infections ◽  
Multiple Infection ◽  
Bacterial Biofilms ◽  
Interspecies Interactions ◽  
Chronic Infections ◽  
Content Type

ABSTRACT The thick mucus within the airways of individuals with cystic fibrosis (CF) promotes frequent respiratory infections that are often polymicrobial. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most prevalent pathogens that cause CF pulmonary infections, and both are among the most common etiologic agents of chronic wound infections. Furthermore, the ability of P. aeruginosa and S. aureus to form biofilms promotes the establishment of chronic infections that are often difficult to eradicate using antimicrobial agents. In this study, we found that multiple LasR-regulated exoproducts of P. aeruginosa, including 2-heptyl-4-hydroxyquinoline N-oxide (HQNO), siderophores, phenazines, and rhamnolipids, likely contribute to the ability of P. aeruginosa PA14 to shift S. aureus Newman norfloxacin susceptibility profiles. Here, we observe that exposure to P. aeruginosa exoproducts leads to an increase in intracellular norfloxacin accumulation by S. aureus. We previously showed that P. aeruginosa supernatant dissipates the S. aureus membrane potential, and furthermore, depletion of the S. aureus proton motive force recapitulates the effect of the P. aeruginosa PA14 supernatant on shifting norfloxacin sensitivity profiles of biofilm-grown S. aureus Newman. From these results, we hypothesize that exposure to P. aeruginosa PA14 exoproducts leads to increased uptake of the drug and/or an impaired ability of S. aureus Newman to efflux norfloxacin. Surprisingly, the effect observed here of P. aeruginosa PA14 exoproducts on S. aureus Newman susceptibility to norfloxacin seemed to be specific to these strains and this antibiotic. Our results illustrate that microbially derived products can alter the ability of antimicrobial agents to kill bacterial biofilms. IMPORTANCE Pseudomonas aeruginosa and Staphylococcus aureus are frequently coisolated from multiple infection sites, including the lungs of individuals with cystic fibrosis (CF) and nonhealing diabetic foot ulcers. Coinfection with P. aeruginosa and S. aureus has been shown to produce worse outcomes compared to infection with either organism alone. Furthermore, the ability of these pathogens to form biofilms enables them to cause persistent infection and withstand antimicrobial therapy. In this study, we found that P. aeruginosa-secreted products dramatically increase the ability of the antibiotic norfloxacin to kill S. aureus biofilms. Understanding how interspecies interactions alter the antibiotic susceptibility of bacterial biofilms may inform treatment decisions and inspire the development of new therapeutic strategies.

scholarly journals Virulence factor landscape of a Staphylococcus aureus sequence type 45 strain, MCRF184

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Vijay Aswani ◽  
Fares Najar ◽  
Madhulatha Pantrangi ◽  
Bob Mau ◽  
William R. Schwan ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factor ◽  
Sequence Type

Inhibition of microbial adherence by sphinganine

1992 ◽  
Vol 38 (9) ◽  
pp. 983-985 ◽  
Author(s):  
Debra Jan Bibel ◽  
Raza Aly ◽  
Henry R. Shinefield
Keyword(s):  
Staphylococcus Aureus ◽  
Infectious Diseases ◽  
Therapeutic Agents ◽  
Eukaryotic Cells ◽  
Buccal Cells ◽  
Streptococcus Mitis ◽  
Buccal Epithelial Cells ◽  
Mucosal Cells ◽  
Microbial Adherence ◽  
Complex Sphingolipids

Sphingosines (precursors and degeneration products of complex sphingolipids) are mediators in membrane second-messenger cascades and in a wide variety of functions in eukaryotic cells. Sphingosines are also lethal for gram-positive microorganisms. In addition to its direct effect, sphinganine is here reported to affect the adherence of Streptococcus mitis to buccal epithelial cells and of Staphylococcus aureus to nasal mucosal cells after incubation for 90 min at 37 °C. When the bacteria were pretreated with 8.1, 16.2, 32.5, or (for Strep. mitis) 65 μM sphinganine for 60 min at 37 °C, adherence counts were reduced for Staph. aureus by 27, 37, and 60% and for Strep. mitis by 19, 44, 54, and 73%, respectively (p < 0.001). In contrast, pretreatment of buccal cells with 81.2 μM lipid increased adherence by 14% (p < 0.01), but no change occurred at either 16.2 or 325 μM lipid. These results further demonstrate the double-edged ability of sphingosines to regulate cellular activities and their potential as multifunctional therapeutic agents for infectious diseases. Key words: adherence, sphingosine, Staphylococcus aureus, Streptococcus mitis.

scholarly journals Total Synthesis of Xanthoangelol B and Its Various Fragments: Toward Inhibition of Virulence Factor Production of Staphylococcus aureus

2018 ◽  
Vol 61 (23) ◽  
pp. 10473-10487 ◽  
Author(s):  
Pushpak Mizar ◽  
Rekha Arya ◽  
Truc Kim ◽  
Soyoung Cha ◽  
Kyoung-Seok Ryu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Total Synthesis ◽  
Virulence Factor ◽  
Factor Production ◽  
Virulence Factor Production

scholarly journals Analogs of Eap Protein Are Conserved and Prevalent in Clinical Staphylococcus aureus Isolates

2001 ◽  
Vol 8 (6) ◽  
pp. 1271-1276 ◽  
Author(s):  
Muzaffar Hussain ◽  
Karsten Becker ◽  
Christof von Eiff ◽  
Georg Peters ◽  
Mathias Herrmann
Keyword(s):  
Staphylococcus Aureus ◽  
Extracellular Matrix ◽  
Staphylococcus Epidermidis ◽  
Translation Termination ◽  
Pcr Analysis ◽  
Cloning And Sequencing ◽  
Extracellular Matrix Molecules ◽  
Size Variability ◽  
Early Translation ◽  
High Degree

ABSTRACT Map and Eap are secreted Staphylococcus aureus proteins that interact with various extracellular matrix molecules. PCR analysis using map primers yielded positive reactions in 97.9% of S. aureus isolates but not in Staphylococcus epidermidis isolates. Cloning and sequencing of the conferring genes revealed a high degree of overall homology combined with size variability of the gene product due to various repeat numbers and early translation termination in a poly(A) region. Thus, Map and Eap may provide a potential novel tool forS. aureus identification and typing.

scholarly journals Discovery of genes encoding a Streptolysin S-like toxin biosynthetic cluster in a select highly pathogenic methicillin resistant Staphylococcus aureus JKD6159 strain

2019 ◽  
Author(s):  
Trevor Kane ◽  
Katelyn E. Carothers ◽  
Yunjuan Bao ◽  
Won-Sik Yeo ◽  
Taeok Bae ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Gene Cluster ◽  
Virulence Factor ◽  
Gene Organization ◽  
Biosynthetic Gene ◽  
Bacterial Gene ◽  
Methicillin Resistant ◽  
Streptolysin S

AbstractBackgroundStaphylococcus aureus (S. aureus) is a major human pathogen owing to its arsenal of virulence factors, as well as its acquisition of multi-antibiotic resistance. Here we report the identification of a Streptolysin S (SLS) like biosynthetic gene cluster in a highly virulent community-acquired methicillin resistant S. aureus (MRSA) isolate, JKD6159. Examination of the SLS-like gene cluster in JKD6159 shows significant homology and gene organization to the SLS-associated biosynthetic gene (sag) cluster responsible for the production of the major hemolysin SLS in Group A Streptococcus.ResultsWe took a comprehensive approach to elucidating the putative role of the sag gene cluster in JKD6159 by constructing a mutant in which one of the biosynthesis genes (sagB homologue) was deleted in the parent JKD6159 strain. Assays to evaluate bacterial gene regulation, biofilm formation, antimicrobial activity, as well as complete host cell response profile and comparative in vivo infections in Balb/Cj mice were conducted.ConclusionsAlthough no significant phenotypic changes were observed in our assays, we postulate that the SLS-like toxin produced by this strain of S. aureus may be a highly specialized virulence factor utilized in specific environments for selective advantage; studies to better understand the role of this newly discovered virulence factor in S. aureus warrant further investigation.

Sign in / Sign up

Export Citation Format

Share Document