Vancomycin-Resistant
            <i>Enterococcus faecium</i>
            : Catheter Colonization,
            <i>esp</i>
            Gene, and Decreased Susceptibility to Antibiotics in Biofilm

Raad, Issam; Hanna, Hend; Boktour, Maha; Chaiban, Gassan; Hachem, Ray; Dvorak, Tanya; Lewis, Russell E.; Murray, Barbara E.

doi:10.1128/aac.49.12.5046-5050.2005

Cited by 57 publications

(38 citation statements)

References 48 publications

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“…Despite the lack of a significant association between Esp and biofilm formation in the current study, other researches reported conflicting results about the role of E. faecalis Esp in biofilm formation (23,42,43,(45)(46)(47)(48). Although biofilm formation in esp-deficient mutants of E. faecalis was not reported in all studies, many others report no correlation between the presence of esp and biofilm formation, which is a multifactorial process (49,50).…”

Section: Discussioncontrasting

confidence: 43%

Virulence Factor and Biofilm Formation in Clinical Enterococcal Isolates of the West of Iran

Azizi¹,

Banafshe²,

Kashef³

et al. 2017

Jundishapur J Microbiol

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Background: Enterococcus spp., a part of the normal flora of the human intestine, possess several virulence factors that can develop biofilms to endure harsh environments. Their ability to cause nosocomial infections makes them as critical opportunistic pathogens in hospital settings. Objectives: The current study aimed at determining the occurrence of 6 genes coding virulence factors and their ability to develop biofilms, and conducting phenotypical assessments of haemolysin and gelatinase in clinical enterococci isolated from the West of Iran. Methods: A total of 126 isolates were screened for harbouring the following genes: aggregation substance (asa1), cytolysin (cylABM), enterococcal surface protein (esp), and gelatinase (gelE). Isolates were tested for haemolysin and gelatinase expression phenotypically and for biofilm production quantitatively, using the microtiter method.Results: Of the 126 tested isolates, 95 (73%) were Enterococcus faecalis and 28 (21%) were E. faecium. The total frequency of virulence gene was cylA 92 (73%), cylB 85 (67%), cylM 57 (45%), asa1 26 (21%), gelE 64 (51%), and esp 66 (53%); while 98 (75%) of the isolates were able to form biofilm. A total of 74 (58%) and 46 (35%) isolates could secret haemolysin and gelatinase. Conclusions: There was a significant difference between the frequency of virulence gene in E. faecalis and E. faecium. Enterococcus faecium isolates lacked the gelE and asa1 genes and the frequency of cylABM genes were lower than that of E. faecalis isolates. Enterococcus faecalis isolates were relatively rich in virulence factors; no association was observed between biofilm formation and the presence of specific virulence genes.

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Section: Discussioncontrasting

confidence: 43%

Virulence Factor and Biofilm Formation in Clinical Enterococcal Isolates of the West of Iran

Azizi¹,

Banafshe²,

Kashef³

et al. 2017

Jundishapur J Microbiol

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“…This low percentage may be explained by the fact that Esp is not essential for intestinal colonization or translocation of Enterococcus faecium and Enterococcus faecalis isolates, as shown in murine models (Heikens et al, 2009). However, Raad et al (2005) and Ruiz-Garbajosa et al (2006) have reported higher percentages of esp carriage among colonizing isolates as compared with infecting ones. Contradictory results have also been published, comparing esp incidence among VRE and VSE (Billström et al, 2008;Duprè et al, 2003;Vankerckhoven et al, 2004;Woodford et al, 2001).…”

Section: Discussionmentioning

confidence: 73%

Biofilm synthesis and presence of virulence factors among enterococci isolated from patients and water samples

Papadimitriou-Olivgeris

Filippidou

Δρούγκα

et al. 2015

Journal of Medical Microbiology

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The goal of this study was to compare biofilm synthesis among enterococci recovered from clinical samples (infection or colonization) of patients as well as environmental samples in order to determine possible virulence factors and clonal relationship. During a two-year period, clinical samples (blood, catheter tips, bronchial secretions, wounds, peritoneal fluid, urine) and rectal swabs collected from hospitalized patients as well as environmental water samples were tested for the presence of Enterococcus faecalis and Enterococcus faecium. Antibiotic susceptibility testing was performed by the disc diffusion method and Etest. Strains were tested for the presence of vanA, vanB, esp, ace and asp genes by PCR. Clones were identified by PFGE (Sma I). From infected patients, 48 strains were identified: 24 Enterococcus faecium (10 vanApositive, 14 vancomycin-susceptible) and 24 Enterococcus faecalis (one vanA-positive, 23 vancomycin-susceptible). Among 143 colonizing isolates, 134 were Enterococcus faecium (58 vanA-positive, 11 vanB-positive, 65 vancomycin-susceptible) and nine Enterococcus faecalis (three vanA-positive, two vanB-positive, four vancomycin-susceptible). Among 167 environmental water samples, 51 Enterococcus faecalis and 19 Enterococcus faecium isolates, all glycopeptide-susceptible, were recovered. In total, 64 strains produced biofilm, whereas 34 were esp-positive, 64 asp-positive and 54 ace-positive. Biofilm production was associated with the presence of esp (P,0.001) and ace genes (P50.021), being higher in infecting (P,0.001) and water (P 0.005) isolates as compared with colonizing ones. Clones of environmental waterstrains were different than the patients' clones. The differences found in the incidence of antibiotic resistance, virulence factors and clones suggest that hospital and water enterococci are of different origin.

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“…Although Esp appeared to be important for biofilm development (20,36,41) in some studies, E. faecalis isolates lacking the esp gene did produce biofilm in vitro (6,12,16,27). Furthermore, for both E. faecium and E. faecalis, isolates were found that carried the esp gene but that failed to produce biofilms.…”

Section: Discussionmentioning

confidence: 97%

“…In a recent study, the N-terminal region of Esp, covering approximately half of the protein in E. faecalis, was identified as the region of the protein involved in biofilm formation (38). In other studies, however, biofilm development appeared to be independent of Esp (6,12,16,27). In E. faecalis, several other factors have been associated with biofilm development, like the sugar-binding transcriptional regulator BopD (13), the quorum-sensing locus fsr (12), heterogeneity in surface charge (43), the bee locus (37), and the secreted metalloprotease GelE (12,16,25).…”

mentioning

confidence: 99%

Growth Condition-Dependent Esp Expression by Enterococcus faecium Affects Initial Adherence and Biofilm Formation

et al. 2007

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A genetic subpopulation of Enterococcus faecium, called clonal complex 17 (CC-17), is strongly associated with hospital outbreaks and invasive infections. Most CC-17 strains contain a putative pathogenicity island encoding the E. faecium variant of enterococcal surface protein (Esp). Western blotting, flow cytometric analyses, and electron microscopy showed that Esp is expressed and exposed on the surface of E. faecium, though Esp expression and surface exposure are highly varied among different strains. Furthermore, Esp expression depends on growth conditions like temperature and anaerobioses. When grown at 37°C, five of six esp-positive E. faecium strains showed significantly increased levels of surface-exposed Esp compared to bacteria grown at 21°C, which was confirmed at the transcriptional level by real-time PCR. In addition, a significant increase in surface-exposed Esp was found in half of these strains when grown at 37°C under anaerobic conditions compared to the level in bacteria grown under aerobic conditions. Finally, amounts of surface-exposed Esp correlated with initial adherence to polystyrene (R 2 ‫؍‬ 0.7146) and biofilm formation (R 2 ‫؍‬ 0.7535). Polystyrene adherence was competitively inhibited by soluble recombinant N-terminal Esp. This study demonstrates that Esp expression on the surface of E. faecium (i) varies consistently between strains, (ii) is growth condition dependent, and (iii) is quantitatively correlated with initial adherence and biofilm formation. These data indicate that E. faecium senses and responds to changing environmental conditions, which might play a role in the early stages of infection when bacteria transit from oxygen-rich conditions at room temperature to anaerobic conditions at body temperature. In addition, variation of surface exposure may explain the contrasting findings reported on the role of Esp in biofilm formation.

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Vancomycin-Resistant Enterococcus faecium : Catheter Colonization, esp Gene, and Decreased Susceptibility to Antibiotics in Biofilm

Cited by 57 publications

References 48 publications

Virulence Factor and Biofilm Formation in Clinical Enterococcal Isolates of the West of Iran

Virulence Factor and Biofilm Formation in Clinical Enterococcal Isolates of the West of Iran

Biofilm synthesis and presence of virulence factors among enterococci isolated from patients and water samples

Growth Condition-Dependent Esp Expression by Enterococcus faecium Affects Initial Adherence and Biofilm Formation

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