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  • Open Access

Distribution of cylA, esp, asa1, hyl and gelE virulence genes among clinical isolates of Enterococcus faecium and Entrococcus faecalis

  • 1,
  • 1,
  • 1,
  • 2 and
  • 1Email author
BMC Infectious Diseases201414 (Suppl 3) :P32

https://doi.org/10.1186/1471-2334-14-S3-P32

  • Published:

Keywords

  • Endocarditis
  • Virulence Factor
  • Hyaluronidase
  • Enterococcus Faecium
  • Enterococcus Species

Background

Enterococci are opportunistic pathogens causing severe urinary tract infections, surgical wound infections, bacteremia and bacterial endocarditis. Aggregation substance (asa1), hemolysin/ cytolysin (cylA), gelatinase (gelE), enterococcal surface protein (esp), hyaluronidase (hyl) and biofilm formation are the major virulence determinants responsible for pathogenicity of enterococci. This study was undertaken to determine virulence factors among clinical Enterococcus species by phenotypic and molecular methods.

Methods

A total of 157 enterococcal isolates obtained from various tertiary care hospitals were characterized by standard biochemical methods. Virulence factors such as gelatinase, cytolysin production by plate method and biofilm formation on 96-well microtitre plate were performed for all the isolates. The presence of cylA, esp, asa1, hyl and gelE genes specific for virulence were analyzed by multiplex PCR with appropriate primers and cycling conditions.

Results

Enterococcus faecium (84/157) was the predominant species obtained, followed by E. faecalis (73/157). 72/157(45.85%) strains were positive for hemolysin, 61/157(38.85%) gelatinase, 16/157(10.19%) strong and 66/157(42%) were moderate biofilm producers phenotypically. PCR results showed, 37/157(23.56%) cylA, 81(51.59%) gelE, 10(6.36%) hyl, 87(55.41%) asa1 and 78(49.68%) isolates were positive for esp genes. Only 25/72, 32/61, 6/16 and 7/16 isolates were phenotypically and genotypically positive for cylA +hemolysin, gelE +gelatinase, esp +biofilm and asa1 +biofilm, respectively. Interestingly, E. faecalis carried multiple virulent genes (>4 genes) when compared with E. faecium among our study isolates.

Conclusion

Hemolysin and gelatinase were the predominant virulence factors expressed phenotypically whereas, asa1>gelE>esp were the predominant genes observed. Majority of E. faecalis isolates were strong and E. faecium were moderate biofilm producers.

Authors’ Affiliations

(1)
Department of Microbiology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai, India
(2)
Department of Paediatric Nephrology, Institute of Child Health and Government Hospital for Children, Egmore, Chennai, India

Copyright

© Padmasini et al; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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