Multilocus sequence typing scheme for Enterococcus faecium - PubMed (original) (raw)
Multilocus sequence typing scheme for Enterococcus faecium
Wieger L Homan et al. J Clin Microbiol. 2002 Jun.
Abstract
A multilocus sequence typing (MLST) scheme has been developed for Enterococcus faecium. Internal fragments from seven housekeeping genes of 123 epidemiologically unlinked isolates from humans and livestock and 16 human-derived isolates from several outbreaks in the United States, the United Kingdom, Australia, and The Netherlands were analyzed. A total of 62 sequence types were detected in vancomycin-sensitive E. faecium (VSEF) and vancomycin-resistant E. faecium (VREF) isolates. VSEF isolates were genetically more diverse than VREF isolates. Both VSEF and VREF isolates clustered in host-specific lineages that were similar to the host-specific clustering obtained by amplified fragment length polymorphism analysis. Outbreak isolates from hospitalized humans clustered in a subgroup that was defined by the presence of a unique allele from the housekeeping gene purK and the surface protein gene esp. The MLST results suggest that epidemic lineages of E. faecium emerged recently worldwide, while genetic variation in both VREF and VSEF was created by longer-term recombination. The results show that MLST of E. faecium provides an excellent tool for isolate characterization and long-term epidemiologic analysis.
Figures
FIG. 1.
Dendrograms showing the genetic relationships among the allele sequences of individual loci used for MLST. The trees were established by analysis of the allele sequences from the seven housekeeping loci by the NJ method. Numbers of VSEF and VREF strains in the different clusters are given to the right of the dendrograms. The scale bar indicates five nucleotide differences. Dots indicate the alleles associated with allele purK6. Bootstrap values of greater than 90% are indicated.
FIG.2.
Dendrogram (categorical, UPGMA) showing the genetic relatedness among the STs of E. faecium. The following data are included: ST; number of strains with the same ST; AFLP group (genogroup determined by AFLP analysis; R, non-A, -B, -C, or -D); host origin (C, calf; H, human; HF, fecal sample from a hospitalized human; HC, clinical sample from a hospitalized human, not outbreak related; HO, clinical sample from a hospitalized human, outbreak related; S, pig; P, poultry); presence of vanA or vanB (A, vanA resistant strain; B, vanB resistant strain; S, sensitive strain); presence of the esp gene; and country (NL, The Netherlands; UK, United Kingdom; USA, United States; Aus or Austr., Australia). The dendrogram is divided by dotted lines into a number of lineages, labeled A to D, similar to the genogroups detected by AFLP analysis (33). Genetically divergent isolates are indicated in bold. n.d., not determined.
References
- Antonishyn, N. A., R. R. McDonald, E. L. Chan, G. Horsman, C. E. Woodmansee, P. S. Falk, and C. G. Mayhall. 2000. Evaluation of fluorescence-based amplified fragment length polymorphism analysis for molecular typing in hospital epidemiology: comparison with pulsed-field gel electrophoresis for typing strains of vancomycin-resistant Enterococcus faecium. J. Clin. Microbiol. 38**:**4058-4065. -PMC -PubMed
- Bergmans, A. M., J. W. Groothedde, J. F. Schellekens, J. D. van Embden, J. M. Ossewaarde, and L. M. Schouls. 1995. Etiology of cat scratch disease: comparison of polymerase chain reaction detection of Bartonella (formerly Rochalimaea) and Afipia felis DNA with serology and skin tests. J. Infect. Dis. 171**:**916-923. -PubMed
- Centers for Disease Control and Prevention. 1999. National nosocomial infections surveillance (NNIS) system report, data summary from January 1990-May 1999, issued June 1999. Am. J. Infect. Control 27**:**520-532. -PubMed
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