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Journal of Clinical Microbiology, September 2009, p. 2713-2719, Vol. 47, No. 9
0095-1137/09/$08.00+0 doi:10.1128/JCM.00667-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
A Trilocus Sequence Typing Scheme for Hospital Epidemiology and Subspecies Differentiation of an Important Nosocomial Pathogen, Enterococcus faecalis
,
Shahreen A. Chowdhury,1,2,3
Cesar A. Arias,1,2,4
Sreedhar R. Nallapareddy,1,2
Jinnethe Reyes,4
Rob J. L. Willems,5 and
Barbara E. Murray1,2,3*
Center for the Study of Emerging and Re-Emerging Pathogens, Division of Infectious Diseases,1 Department of Internal Medicine,2 Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, Texas,3 Molecular Genetics and Antimicrobial Resistance Unit, Universidad El Bosque, Bogota, Colombia,4 Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands5
Received 1 April 2009/ Returned for modification 21 May 2009/ Accepted 25 June 2009
In this study, we present a trilocus sequence typing (TLST) scheme based on intragenic regions of two antigenic genes, ace and salA (encoding a collagen/laminin adhesin and a cell wall-associated antigen, respectively), and a gene associated with antibiotic resistance, lsa (encoding a putative ABC transporter), for subspecies differentiation of Enterococcus faecalis. Each of the alleles was analyzed using 50 E. faecalis isolates representing 42 diverse multilocus sequence types (STM; based on seven housekeeping genes) and four groups of clonally linked (by pulsed-field gel electrophoresis [PFGE]) isolates. The allelic profiles and/or concatenated sequences of the three genes agreed with multilocus sequence typing (MLST) results for typing of 49 of the 50 isolates; in addition to the one exception, two isolates were found to have identical TLST types but were single-locus variants (differing by a single nucleotide) by MLST and were therefore also classified as clonally related by MLST. TLST was also comparable to PFGE for establishing short-term epidemiological relationships, typing all isolates classified as clonally related by PFGE with the same type. TLST was then applied to representative isolates (of each PFGE subtype and isolation year) of a collection of 48 hospital isolates and demonstrated the same relationships between isolates of an outbreak strain as those found by MLST and PFGE. In conclusion, the TLST scheme described here was shown to be successful for investigating short-term epidemiology in a hospital setting and may provide an alternative to MLST for discriminating isolates.
* Corresponding author. Mailing address: Division of Infectious Diseases, Department of Internal Medicine, Center for the Study of Emerging and Re-Emerging Pathogens, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 2.112, Houston, TX 77030. Phone: (713) 500-6745. Fax: (713) 500-6766. E-mail: bem.asst{at}uth.tmc.edu
Published ahead of print on 1 July 2009.
Supplemental material for this article may be found at http://jcm.asm.org/.
Journal of Clinical Microbiology, September 2009, p. 2713-2719, Vol. 47, No. 9
0095-1137/09/$08.00+0 doi:10.1128/JCM.00667-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
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