Virulence of enterococci

Abstract

Enterococci are commensal organisms well suited to survival in intestinal and vaginal tracts and the oral cavity. However, as for most bacteria described as causing human disease, enterococci also possess properties that can be ascribed roles in pathogenesis. The natural ability of enterococci to readily acquire, accumulate, and share extrachromosomal elements encoding virulence traits or antibiotic resistance genes lends advantages to their survival under unusual environmental stresses and in part explains their increasing importance as nosocomial pathogens. This review discusses the current understanding of enterococcal virulence relating to (i) adherence to host tissues, (ii) invasion and abscess formation, (iii) factors potentially relevant to modulation of host inflammatory responses, and (iv) potentially toxic secreted products. Aggregation substance, surface carbohydrates, or fibronectin-binding moieties may facilitate adherence to host tissues. Enterococcus faecalis appears to have the capacity to translocate across intact intestinal mucosa in models of antibiotic-induced superinfection. Extracellular toxins such as cytolysin can induce tissue damage as shown in an endophthalmitis model, increase mortality in combination with aggregation substance in an endocarditis model, and cause systemic toxicity in a murine peritonitis model. Finally, lipoteichoic acid, superoxide production, or pheromones and corresponding peptide inhibitors each may modulate local inflammatory reactions.

Enterococci as emerging pathogens of humans

“…Maki and Agger (1988) showed that nosocomial bacteraemias increased markedly between 1973 The virulence of enterococci has been reviewed by Jett et al (1994). A number of virulence factors have been implicated and 1983 against a constant 'back-drop' of community-acquired enterococcal bacteraemias.…”

Classification and overview of the genera Streptococcus and Enterococcus

“…virulence determinants of enterococci, which include a cytolysin, aggregation substance, pheromones, lipoteichoic acid, a protease, Enterococci are typically found in the intestinal tract and faeces of man and other animals (Murray 1990;Devriese and hyaluronidase and a bacteriocin, 45-48 (Jett et al 1994). As well as being well adapted for survival in the body, Pot 1995).…”

Defensive Effects of Human Antimicrobial Peptide .ALPHA.-Defensins against Enterococcus faecalis

“…14) Like other enterococci, E. faecalis causes life-threatening nosocomial infections because of its high multidrug resistantce. [15][16][17] Additionally, the production of toxic or virulent factors, such as adhensin, hemolysin, and gelatinase, may be related to the pathogenicity of this species. [15][16][17] In particular, the gelatinase GelE has been studied as an important toxic factor involved in bacterial invasion.…”

“…[15][16][17] Additionally, the production of toxic or virulent factors, such as adhensin, hemolysin, and gelatinase, may be related to the pathogenicity of this species. [15][16][17] In particular, the gelatinase GelE has been studied as an important toxic factor involved in bacterial invasion. 18,19) Additionally, this extracellular enzyme can digest many host proteins including fibrinogen, fibronectin, collagen, and laminin.…”

“…18,19) Additionally, this extracellular enzyme can digest many host proteins including fibrinogen, fibronectin, collagen, and laminin. 15,18) GelE is a metalloprotease containing one zinc ion in the active center and is classified into the thermolysin family. 19) In this study, we examined whether two major human α-defensins, HNP-3 and HD-5 ( Fig.…”