scholarly journals Gelatinase-Associated Phenotypes and Genotypes Among Clinical Isolates of Enterococcus faecalis in Poland

2011 ◽  
Vol 60 (4) ◽  
pp. 287-292 ◽  
Author(s):  
JANUSZ STRZELECKI ◽  
WALERIA HRYNIEWICZ ◽  
EWA SADOWY
Keyword(s):  
Gene Expression ◽  
Enterococcus Faecalis ◽  
Clonal Complex ◽  
Nosocomial Pathogen ◽  
Gelatinase Activity ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Invasive Infections ◽  
Genetic Events ◽  
Negative Phenotype

Enterococcus faecalis is an important nosocomial pathogen causing serious invasive infections. One of the virulence factors of this pathogen, gelatinase GelE, is a protease whose gene expression is regulated by the Fsr quorum sensing system. In this study, we used a well-characterized collection of 153 clinical E. faecalis isolates to investigate the distribution of genes involved in gelatinase expression. Although 140 isolates (91% of the group) harbored the gelE gene, only 81 isolates (53%) produced active gelatinase. The gelatinase-negative phenotype was found in several unrelated clones, and appeared to be caused by various genetic events. Isolates of the hospital-adapted clonal complex 2 (CC2) and of CC40 were uniformly gelatinase-positive, while all the CC87 isolates contained the 23.9 kb deletion encompassing most of the fsr locus and were gelatinase-negative. No significant differences among isolates of different clinical origin and gelatinase activity or presence of the fsr genes were found with the exception of isolates from cerebrospinal fluid, which were more often gelatinase-positive than colonizing isolates.

scholarly journals IS256 abolishes gelatinase activity and biofilm formation in a mutant of the nosocomial pathogen Enterococcus faecalis V583

2015 ◽  
Vol 61 (7) ◽  
pp. 517-519 ◽  
Author(s):  
Marta Perez ◽  
Marina Calles-Enríquez ◽  
Beatriz del Rio ◽  
Victor Ladero ◽  
María Cruz Martín ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Biofilm Formation ◽  
Nucleotide Position ◽  
Gelatinase Activity ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Life Threatening ◽  
Dna Fragment ◽  
Encoding Genes ◽  
And Staphylococcus Aureus

Enterococcus faecalis is one of the most controversial species of lactic acid bacteria. Some strains are used as probiotics, while others are associated with severe and life-threatening nosocomial infections. Their pathogenicity depends on the acquisition of multidrug resistance and virulence factors. Gelatinase, which is required in the first steps of biofilm formation, is an important virulence determinant involved in E. faecalis pathogenesis, including endocarditis and peritonitis. The gene that codes for gelatinase (gelE) is controlled by the Fsr quorum-sensing system, whose encoding genes (fsrA, fsrB, fsrC, and fsrD) are located immediately upstream of gelE. The integration of a DNA fragment into the fsr locus of a derived mutant of E. faecalis V583 suppressed the gelatinase activity and prevented biofilm formation. Sequence analysis indicated the presence of IS256 integrated into the fsrC gene at nucleotide position 321. Interestingly, IS256 is also associated with biofilm formation in Staphylococcus epidermidis and Staphylococcus aureus. This is the first description of an insertion sequence that prevents biofilm formation in E. faecalis.

scholarly journals Description of a 23.9-Kilobase Chromosomal Deletion Containing a Region Encoding fsr Genes Which Mainly Determines the Gelatinase-Negative Phenotype of Clinical Isolates of Enterococcus faecalis in Urine

2002 ◽  
Vol 68 (6) ◽  
pp. 3152-3155 ◽  
Author(s):  
Jiro Nakayama ◽  
Reiko Kariyama ◽  
Hiromi Kumon
Keyword(s):  
Quorum Sensing ◽  
Serine Protease ◽  
Gene Cluster ◽  
Enterococcus Faecalis ◽  
Clinical Isolates ◽  
Chromosomal Deletion ◽  
Extracellular Proteases ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Negative Phenotype

ABSTRACT Expression of virulence-related extracellular proteases, gelatinase, and serine protease of Enterococcus faecalis is regulated by a quorum-sensing system encoded by the fsr gene cluster. In this study, a 23.9-kb chromosomal deletion containing the fsr gene cluster region was found to be present in the majority (79%) of gelatinase-negative clinical isolates of E. faecalis from urine.

The Virulence Associated fsr Quorum Sensing System Play Key Roles in Enterococcus Faecalis

2021 ◽  
Author(s):  
Jinglin Yue ◽  
Pengcheng Du ◽  
Mingxi Hua ◽  
Xinzhe Liu ◽  
Ang Duan ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Quorum Sensing ◽  
Genome Size ◽  
Enterococcus Faecalis ◽  
Genomic Analysis ◽  
Antibiotic Prescribing ◽  
Human Origins ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Tract Infections

Abstract Enterococcus faecalis, a major nosocomial pathogen, has become a top leading cause of hospital-acquired infections including urinary tract infections, endocarditis and bacteremia. It is important to study the epidemiology and virulence characteristics of E. faecalis isolates in order to tailor infection prevention and antibiotic prescribing. In this study, comparative genomic analysis was conducted on 537 isolates from different human origins. The isolates from bloodstream and intra-abdominal lining had the largest and smallest average genome size respectively, while the isolates from open natural orifices (gastrointestinal tract, urinary tract, respiratory tract, wound and eye) had medium average genome size. The phylogenetic relationships were expounded that the strain isolation niche is uncorrelated with strain phylogeny. Six clonal complexes generally appeared in different isolation sources. Furthermore, genomic analysis revealed differences at the accessory genome, the functions of different genes mainly pointed to the virulence, drug resistance and metabolism of E. faecalis. Interestingly, fsr quorum sensing system genes affecting biofilm formation had a highest proportion in the blood-derived strains. This study showed the genomic characteristics of different human origins and suggested that fsr quorum-sensing system maybe a contributing factor of bacteremia due to E. faecalis infection.

scholarly journals The Enterococcus faecalis fsrB Gene, a Key Component of the fsr Quorum-Sensing System, Is Associated with Virulence in the Rabbit Endophthalmitis Model

2002 ◽  
Vol 70 (8) ◽  
pp. 4678-4681 ◽  
Author(s):  
Eleftherios Mylonakis ◽  
Michael Engelbert ◽  
Xiang Qin ◽  
Costi D. Sifri ◽  
Barbara E. Murray ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Enterococcus Faecalis ◽  
Deletion Mutant ◽  
Wild Type ◽  
Sensing System ◽  
Quorum Sensing System

ABSTRACT We used a rabbit endophthalmitis model to explore the role of fsrB, a gene required for the function of the fsr quorum-sensing system of Enterococcus faecalis, in pathogenicity. A nonpolar deletion mutant of fsrB had significantly reduced virulence compared to wild type. Complementation of mutation restored virulence. These data corroborate the role of fsrB in E. faecalis pathogenesis and suggest that the rabbit endophthalmitis model can be used to study the in vivo role of quorum sensing.

scholarly journals The LuxR Homolog ExpR, in Combination with the Sin Quorum Sensing System, Plays a Central Role in Sinorhizobium meliloti Gene Expression

2004 ◽  
Vol 186 (16) ◽  
pp. 5460-5472 ◽  
Author(s):  
Hanh H. Hoang ◽  
Anke Becker ◽  
Juan E. González
Keyword(s):  
Gene Expression ◽  
Quorum Sensing ◽  
Sinorhizobium Meliloti ◽  
Regulation Of Gene Expression ◽  
Bacterial Communication ◽  
Cellular Processes ◽  
Sensing System ◽  
Dna Microarray Data ◽  
Luxr Homolog ◽  
Quorum Sensing System

ABSTRACT Quorum sensing, a population density-dependent mechanism for bacterial communication and gene regulation, plays a crucial role in the symbiosis between alfalfa and its symbiont Sinorhizobium meliloti. The Sin system, one of three quorum sensing systems present in S. meliloti, controls the production of the symbiotically active exopolysaccharide EPS II. Based on DNA microarray data, the Sin system also seems to regulate a multitude of S. meliloti genes, including genes that participate in low-molecular-weight succinoglycan production, motility, and chemotaxis, as well as other cellular processes. Most of the regulation by the Sin system is dependent on the presence of the ExpR regulator, a LuxR homolog. Gene expression profiling data indicate that ExpR participates in additional cellular processes that include nitrogen fixation, metabolism, and metal transport. Based on our microarray analysis we propose a model for the regulation of gene expression by the Sin/ExpR quorum sensing system and another possible quorum sensing system(s) in S. meliloti.

scholarly journals Quorum Sensing Controls Exopolysaccharide Production in Sinorhizobium meliloti

2003 ◽  
Vol 185 (1) ◽  
pp. 325-331 ◽  
Author(s):  
Melanie M. Marketon ◽  
Sarah A. Glenn ◽  
Anatol Eberhard ◽  
Juan E. González
Keyword(s):  
Gene Expression ◽  
Quorum Sensing ◽  
Sinorhizobium Meliloti ◽  
Wild Type Strain ◽  
Homoserine Lactone ◽  
Symbiotic Relationship ◽  
Wild Type ◽  
Sensing System ◽  
Quorum Sensing System

ABSTRACT Sinorhizobium meliloti is a soil bacterium capable of invading and establishing a symbiotic relationship with alfalfa plants. This invasion process requires the synthesis, by S. meliloti, of at least one of the two symbiotically important exopolysaccharides, succinoglycan and EPS II. We have previously shown that the sinRI locus of S. meliloti encodes a quorum-sensing system that plays a role in the symbiotic process. Here we show that the sinRI locus exerts one level of control through regulation of EPS II synthesis. Disruption of the autoinducer synthase gene, sinI, abolished EPS II production as well as the expression of several genes in the exp operon that are responsible for EPS II synthesis. This phenotype was complemented by the addition of acyl homoserine lactone (AHL) extracts from the wild-type strain but not from a sinI mutant, indicating that the sinRI-specified AHLs are required for exp gene expression. This was further confirmed by the observation that synthetic palmitoleyl homoserine lactone (C16:1-HL), one of the previously identified sinRI-specified AHLs, specifically restored exp gene expression. Most importantly, the absence of symbiotically active EPS II in a sinI mutant was confirmed in plant nodulation assays, emphasizing the role of quorum sensing in symbiosis.

scholarly journals Regulation of Motility by the ExpR/Sin Quorum-Sensing System in Sinorhizobium meliloti

2007 ◽  
Vol 190 (3) ◽  
pp. 861-871 ◽  
Author(s):  
Hanh H. Hoang ◽  
Nataliya Gurich ◽  
Juan E. González
Keyword(s):  
Gene Expression ◽  
Quorum Sensing ◽  
Sinorhizobium Meliloti ◽  
Flagellar Apparatus ◽  
Sensing System ◽  
Physiological Processes ◽  
Genome Expression ◽  
Proposed Model ◽  
Quorum Sensing System ◽  
Whole Genome Expression

ABSTRACT A successful symbiotic relationship between Sinorhizobium meliloti and its host Medicago sativa (alfalfa) depends on several signaling mechanisms, such as the biosynthesis of exopolysaccharides (EPS) by S. meliloti. Previous work in our laboratory has shown that a quorum-sensing mechanism controls the production of the symbiotically active EPS II. Recent microarray analysis of the whole-genome expression profile of S. meliloti reveals that the ExpR/Sin quorum-sensing system regulates additional physiological processes that include low-molecular-weight succinoglycan production, nitrogen utilization, metal transport, motility, and chemotaxis. Nearly half of the flagellar genes and their dependence on quorum sensing are prominently displayed in our microarray analyses. We extend those observations in this work and confirm the findings by real-time PCR expression analysis of selected genes, including the flaF, flbT, flaC, cheY1, and flgB genes, involved in motility and chemotaxis. These genes code for regulators of flagellum synthesis, the chemotactic response, or parts of the flagellar apparatus. Gene expression analyses and visualization of flagella by electron microscopy performed at different points in the growth phase support our proposed model in which quorum sensing downregulates motility in S. meliloti. We demonstrate that the ExpR/Sin quorum-sensing system controls motility gene expression through the VisN/VisR/Rem relay. We also show that the ExoS-dependent two-component system suppresses motility gene expression through VisN and Rem in parallel to quorum sensing. This study contributes to our understanding of the mechanisms that govern motility in S. meliloti.

scholarly journals Revised Model for Enterococcus faecalis fsr Quorum-Sensing System: the Small Open Reading Frame fsrD Encodes the Gelatinase Biosynthesis-Activating Pheromone Propeptide Corresponding to Staphylococcal AgrD

2006 ◽  
Vol 188 (23) ◽  
pp. 8321-8326 ◽  
Author(s):  
Jiro Nakayama ◽  
Shengmin Chen ◽  
Nozomi Oyama ◽  
Kenzo Nishiguchi ◽  
Essam A. Azab ◽  
...  
Keyword(s):  
Amino Acid ◽  
Quorum Sensing ◽  
Amino Acid Sequence ◽  
Enterococcus Faecalis ◽  
Cysteine Protease ◽  
Open Reading Frame ◽  
Reading Frame ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Small Open Reading Frame

ABSTRACT Gelatinase biosynthesis-activating pheromone (GBAP) is an autoinducing peptide involved in Enterococcus faecalis fsr quorum sensing, and its 11-amino-acid sequence has been identified in the C-terminal region of the 242-residue deduced fsrB product (J. Nakayama et al., Mol. Microbiol. 41:145-154, 2001). In this study, however, we demonstrated the existence of fsrD, encoding the GBAP propeptide, which is in frame with fsrB but is translated independently of fsrB. It was also demonstrated that FsrB′, an FsrD segment-truncated FsrB, functions as a cysteine protease-like processing enzyme to generate GBAP from FsrD. This revised model is consistent with the staphylococcal agr system.

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