Skip to main content
  • ASM
    • Antimicrobial Agents and Chemotherapy
    • Applied and Environmental Microbiology
    • Clinical Microbiology Reviews
    • Clinical and Vaccine Immunology
    • EcoSal Plus
    • Eukaryotic Cell
    • Infection and Immunity
    • Journal of Bacteriology
    • Journal of Clinical Microbiology
    • Journal of Microbiology & Biology Education
    • Journal of Virology
    • mBio
    • Microbiology and Molecular Biology Reviews
    • Microbiology Resource Announcements
    • Microbiology Spectrum
    • Molecular and Cellular Biology
    • mSphere
    • mSystems
  • Log in
  • My alerts
  • My Cart

Main menu

  • Home
  • Articles
    • Current Issue
    • Accepted Manuscripts
    • COVID-19 Special Collection
    • Archive
    • Minireviews
  • For Authors
    • Submit a Manuscript
    • Scope
    • Editorial Policy
    • Submission, Review, & Publication Processes
    • Organization and Format
    • Errata, Author Corrections, Retractions
    • Illustrations and Tables
    • Nomenclature
    • Abbreviations and Conventions
    • Publication Fees
    • Ethics Resources and Policies
  • About the Journal
    • About JCM
    • Editor in Chief
    • Editorial Board
    • For Reviewers
    • For the Media
    • For Librarians
    • For Advertisers
    • Alerts
    • RSS
    • FAQ
  • Subscribe
    • Members
    • Institutions
  • ASM
    • Antimicrobial Agents and Chemotherapy
    • Applied and Environmental Microbiology
    • Clinical Microbiology Reviews
    • Clinical and Vaccine Immunology
    • EcoSal Plus
    • Eukaryotic Cell
    • Infection and Immunity
    • Journal of Bacteriology
    • Journal of Clinical Microbiology
    • Journal of Microbiology & Biology Education
    • Journal of Virology
    • mBio
    • Microbiology and Molecular Biology Reviews
    • Microbiology Resource Announcements
    • Microbiology Spectrum
    • Molecular and Cellular Biology
    • mSphere
    • mSystems

User menu

  • Log in
  • My alerts
  • My Cart

Search

  • Advanced search
Journal of Clinical Microbiology
publisher-logosite-logo

Advanced Search

  • Home
  • Articles
    • Current Issue
    • Accepted Manuscripts
    • COVID-19 Special Collection
    • Archive
    • Minireviews
  • For Authors
    • Submit a Manuscript
    • Scope
    • Editorial Policy
    • Submission, Review, & Publication Processes
    • Organization and Format
    • Errata, Author Corrections, Retractions
    • Illustrations and Tables
    • Nomenclature
    • Abbreviations and Conventions
    • Publication Fees
    • Ethics Resources and Policies
  • About the Journal
    • About JCM
    • Editor in Chief
    • Editorial Board
    • For Reviewers
    • For the Media
    • For Librarians
    • For Advertisers
    • Alerts
    • RSS
    • FAQ
  • Subscribe
    • Members
    • Institutions
Bacteriology

Evaluation of the Vitek 2 System with a Variety of Staphylococcus Species

Julien Delmas, Jean Paul Chacornac, Frédéric Robin, Philippe Giammarinaro, Régine Talon, Richard Bonnet
Julien Delmas
1CHU Clermont-Ferrand, Centre de Biologie, Laboratoire de Bactériologie Clinique, Clermont-Ferrand F-63003, France
2Université Clermont 1, UFR Médecine, Laboratoire de Bactériologie, EA3844, Clermont-Ferrand F-63001, France
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Jean Paul Chacornac
3INRA, Centre de Clermont-Ferrand-Theix, UR 454, Microbiologie, 63122 Saint-Genes Champanelle, France
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Frédéric Robin
1CHU Clermont-Ferrand, Centre de Biologie, Laboratoire de Bactériologie Clinique, Clermont-Ferrand F-63003, France
2Université Clermont 1, UFR Médecine, Laboratoire de Bactériologie, EA3844, Clermont-Ferrand F-63001, France
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Philippe Giammarinaro
3INRA, Centre de Clermont-Ferrand-Theix, UR 454, Microbiologie, 63122 Saint-Genes Champanelle, France
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Régine Talon
3INRA, Centre de Clermont-Ferrand-Theix, UR 454, Microbiologie, 63122 Saint-Genes Champanelle, France
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Richard Bonnet
1CHU Clermont-Ferrand, Centre de Biologie, Laboratoire de Bactériologie Clinique, Clermont-Ferrand F-63003, France
2Université Clermont 1, UFR Médecine, Laboratoire de Bactériologie, EA3844, Clermont-Ferrand F-63001, France
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: rbonnet@chu-clermontferrand.fr
DOI: 10.1128/JCM.01610-07
  • Article
  • Figures & Data
  • Info & Metrics
  • PDF
Loading

ABSTRACT

The Vitek 2 gram-positive (GP) card was compared with an oligonucleotide array approach for the identification of 190 Staphylococcus strains, including 35 species, isolated from clinical and environmental specimens. The GP card provided a rapid and reliable identification of most species, whatever their origin.

Staphylococci are widespread in nature and can be isolated from humans and animals and from various food products (4, 5, 11, 13, 15). Some staphylococcal strains are associated with diseases in humans or animals, and others are used for technological purposes (4, 14, 15). Staphylococcus aureus is a well documented pathogen. Of the non-S. aureus staphylococci, S. epidermidis, S. haemolyticus, and S. saprophyticus are those most frequently implicated in disease in humans (4, 9, 15). Other staphylococcal species, such as S. hominis and S. warneri, can be found as contaminants of blood cultures but can also be associated with a variety of infections. In food, particularly in fermented meat products, staphylococci such as S. xylosus, S. carnosus, S. simulans, S. warneri, S. epidermidis, and S. saprophyticus may be found (1). S. xylosus and S. carnosus strains are used as starter cultures in fermented meat products because they contribute to their color and flavor (14). However, the presence of S. aureus in food is a potential public health hazard, since many strains of S. aureus produce enterotoxins (7, 10). Accurate identification of the Staphylococcus species is therefore of great importance in microbiological laboratories.

The Vitek 2 system used with the gram-positive (GP) identification card (bioMérieux, Marcy l'Etoile, France) is an automated machine designed to provide rapid and accurate phenotypic identifications for most clinical staphylococci (2, 6, 8, 16). The colorimetric GP card contains 43 tests. The database of the GP card particularly includes the environmental species S. caprae, S. carnosus, S. equorum, S. gallinarum, and S. vitulinus. However, there has been no documented assessment of this identification card for any collection of Staphylococcus strains, including environmental isolates. The purpose of this study was to assess the ability of the Vitek 2 GP card to identify Staphylococcus species of clinical and environmental origins.

A total of 190 Staphylococcus strains, including 38 type strains representing 35 species (Table 1) and 152 strains from our collection, were studied (Table 2). The latter 152 strains were isolated from clinical samples (n = 60) and from food and plant samples (n = 92). The GP card was used in accordance with the recommendations of the manufacturer. The results were compared with those of the oligonucleotide “Staph array,” a method, which is based on the hybridization of the internal part of the sodA gene (3). The strain was retested with the GP card if the identification results differed between the two methods. In case of a persistent discrepancy, the Staph array identifications were confirmed by DNA sequencing of the sodA gene (12). Results from the GP card were separated into four groups: (i) the “one-choice identification” group corresponded to identical identifications for the GP card and Staph array; (ii) the “low level of discrimination” group corresponded to results for which the GP card indicated the possibility of two or three species, including the result of Staph array and proposed supplementary tests (pigmentation, hemolysis, or novobiocin resistance) to determine the correct identification; (iii) the “misidentification” group corresponded to different identifications for the GP card and Staph array; and (iv) the “no identification” group corresponded to strains for which the GP card gave no result. Correct identification was defined as the association of the first two groups.

Twenty-four reference strains out of 38 (63%) were correctly identified by the GP card (Table 1). Of the 14 misidentified reference strains, 10 were species not included in the database of the GP card. The four other strains were S. capitis subsp. capitis, identified as S. equorum; S. equorum subsp. equorum, identified as S. xylosus; S. haemolyticus, identified as S. warneri/S. pasteuri; and S. vitulinus, identified as S. sciuri. In a study by Layer et al. (6), 70% (20 out of 27) of reference strains were correctly identified. However, the misidentified strains belonged to different species.

Fifty-six of the 60 clinical strains (93.3%), belonging to 14 different species, were identified from the collection. Complementary tests were necessary for three strains. These results were in agreement with those reported by Layer et al. (6). Two other studies found higher identification accuracy (98.2 to 99.3%) (2, 16). In those studies, the numbers of taxa tested and their proportions were different; 66 and 74% of clinical strains belonged to the three species S. aureus, S. epidermidis, and S. hominis, versus only 37% in our study. Three strains belonging to the species S. saprophyticus, S. simulans, and S. delphini were misidentified, and one strain of S. capitis was not identified.

The GP card also correctly identified 67 of the 92 environmental strains (73%). Complementary tests were necessary for 10 strains. Twenty-three strains (25%), belonging to five species, were misidentified (Table 2). Nine misidentified strains belonged to S. fleurettii (n = 1) and S. succinus (n = 8), which were absent in the database of the GP card. Eleven of the 14 remaining misidentified strains were S. equorum strains, which were frequently reported as S. xylosus (n = 10). The last three misidentified strains belonged to S. carnosus and S. vitulinus. One strain each of S. fleurettii and S. succinus were not identified as expected. Except for S. equorum (n = 13) and S. succinus (n = 9), 65 of the 70 environmental strains were correctly identified (92.9%). The misidentifications of S. equorum as S. xylosus were suspected with the vibriostatic O129 test of the GP card. Indeed, all the strains identified as S. xylosus which had a negative test with the vibriostatic compound were misidentified strains. According to our data, the identifications of S. xylosus, S. sciuri, and S. auricularis provided by the GP card required complementary tests for confirmation (Table 3).

In conclusion, the Vitek 2 GP card allowed the identification of 123 (93.2%; n = 132) Staphylococcus strains belonging to the species which are included in the database. The results obtained in this study highlight the interesting performance of the colorimetric Vitek 2 GP card, which can be used in clinical, agrochemical, and food laboratories. However, the GP card demonstrated low accuracy in identification of the species S. equorum and misidentified S. succinus, which is not included in the current Vitek 2 GP database.

View this table:
  • View inline
  • View popup
TABLE 1.

Identifications obtained with the GP card for 38 Staphylococcus reference strains

View this table:
  • View inline
  • View popup
TABLE 2.

GP card identification of staphylococci in the laboratory collection

View this table:
  • View inline
  • View popup
TABLE 3.

Routinely collected laboratory strains misidentified with the GP card

ACKNOWLEDGMENTS

bioMérieux, La-Balme les Grottes, France, provided the study materials. We thank Sonia Chatellier for support and helpful critical comments.

FOOTNOTES

    • Received 13 August 2007.
    • Returned for modification 2 October 2007.
    • Accepted 15 October 2007.
  • Copyright © 2008 American Society for Microbiology

REFERENCES

  1. 1.↵
    Blaiotta, G., C. Pennacchia, F. Villani, A. Ricciardi, R. Tofalo, and E. Parente. 2004. Diversity and dynamics of communities of coagulase-negative staphylococci in traditional fermented sausages. J. Appl. Microbiol.97:271-284.
    OpenUrlCrossRefPubMed
  2. 2.↵
    Funke, G., and P. Funke-Kissling. 2005. Performance of the new VITEK 2 GP card for identification of medically relevant gram-positive cocci in a routine clinical laboratory. J. Clin. Microbiol.43:84-88.
    OpenUrlAbstract/FREE Full Text
  3. 3.↵
    Giammarinaro, P., S. Leroy, J. P. Chacornac, J. Delmas, and R. Talon. 2005. Development of a new oligonucleotide array to identify staphylococcal strains at species level. J. Clin. Microbiol.43:3673-3680.
    OpenUrlAbstract/FREE Full Text
  4. 4.↵
    Huebner, J., and D. A. Goldmann. 1999. Coagulase-negative staphylococci: role as pathogens. Annu. Rev. Med.50:223-236.
    OpenUrlCrossRefPubMedWeb of Science
  5. 5.↵
    Jousson, O., D. Di Bello, M. Vanni, G. Cardini, G. Soldani, C. Pretti, and L. Intorre. 2007. Genotypic versus phenotypic identification of staphylococcal species of canine origin with special reference to Staphylococcus schleiferi subsp. coagulans. Vet. Microbiol.123:238-244.
    OpenUrlCrossRefPubMed
  6. 6.↵
    Layer, F., B. Ghebremedhin, K. A. Moder, W. Konig, and B. Konig. 2006. Comparative study using various methods for identification of Staphylococcus species in clinical specimens. J. Clin. Microbiol.44:2824-2830.
    OpenUrlAbstract/FREE Full Text
  7. 7.↵
    Le Loir, Y., F. Baron, and M. Gautier. 2003. Staphylococcus aureus and food poisoning. Genet. Mol. Res.2:63-76.
    OpenUrlPubMed
  8. 8.↵
    Ligozzi, M., C. Bernini, M. G. Bonora, M. De Fatima, J. Zuliani, and R. Fontana. 2002. Evaluation of the VITEK 2 system for identification and antimicrobial susceptibility testing of medically relevant gram-positive cocci. J. Clin. Microbiol.40:1681-1686.
    OpenUrlAbstract/FREE Full Text
  9. 9.↵
    Martineau, F., F. J. Picard, D. Ke, S. Paradis, P. H. Roy, M. Ouellette, and M. G. Bergeron. 2001. Development of a PCR assay for identification of staphylococci at genus and species levels. J. Clin. Microbiol.39:2541-2547.
    OpenUrlAbstract/FREE Full Text
  10. 10.↵
    Palavecino, E. 2004. Community-acquired methicillin-resistant Staphylococcus aureus infections. Clin. Lab. Med.24:403-418.
    OpenUrlCrossRefPubMedWeb of Science
  11. 11.↵
    Papamanoli, E., P. Kotzekidou, N. Tzanetakis, and E. Litopoulou-Tzanetaki. 2002. Characterization of Micrococcaceae isolated from dry fermented sausage. Food Microbiol.19:441-449.
    OpenUrlCrossRef
  12. 12.↵
    Poyart, C., G. Quesne, C. Boumaila, and P. Trieu-Cuot. 2001. Rapid and accurate species-level identification of coagulase-negative staphylococci by using the sodA gene as a target. J. Clin. Microbiol.39:4296-4301.
    OpenUrlAbstract/FREE Full Text
  13. 13.↵
    Rich, M. 2005. Staphylococci in animals: prevalence, identification and antimicrobial susceptibility, with an emphasis on methicillin-resistant Staphylococcus aureus. Br. J. Biomed. Sci.62:98-105.
    OpenUrlPubMedWeb of Science
  14. 14.↵
    Talon, R., S. Leroy-Sétrin, and S. Fadda. 2002. Bacterial starters involved in the quality of fermented meat products, p. 175-191. In F. Toldrá (ed.), Research advances in quality of meat and meat products. Research Signpost, Trivandrum, Kerala, India.
  15. 15.↵
    von Eiff, C., G. Peters, and C. Heilmann. 2002. Pathogenesis of infections due to coagulase-negative staphylococci. Lancet Infect. Dis.2:677-685.
    OpenUrlCrossRefPubMedWeb of Science
  16. 16.↵
    Wallet, F., C. Loiez, E. Renaux, N. Lemaitre, and R. J. Courcol. 2005. Performances of VITEK 2 colorimetric cards for identification of gram-positive and gram-negative bacteria. J. Clin. Microbiol.43:4402-4406.
    OpenUrlAbstract/FREE Full Text
View Abstract
PreviousNext
Back to top
Download PDF
Citation Tools
Evaluation of the Vitek 2 System with a Variety of Staphylococcus Species
Julien Delmas, Jean Paul Chacornac, Frédéric Robin, Philippe Giammarinaro, Régine Talon, Richard Bonnet
Journal of Clinical Microbiology Jan 2008, 46 (1) 311-313; DOI: 10.1128/JCM.01610-07

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Print

Alerts
Sign In to Email Alerts with your Email Address
Email

Thank you for sharing this Journal of Clinical Microbiology article.

NOTE: We request your email address only to inform the recipient that it was you who recommended this article, and that it is not junk mail. We do not retain these email addresses.

Enter multiple addresses on separate lines or separate them with commas.
Evaluation of the Vitek 2 System with a Variety of Staphylococcus Species
(Your Name) has forwarded a page to you from Journal of Clinical Microbiology
(Your Name) thought you would be interested in this article in Journal of Clinical Microbiology.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Share
Evaluation of the Vitek 2 System with a Variety of Staphylococcus Species
Julien Delmas, Jean Paul Chacornac, Frédéric Robin, Philippe Giammarinaro, Régine Talon, Richard Bonnet
Journal of Clinical Microbiology Jan 2008, 46 (1) 311-313; DOI: 10.1128/JCM.01610-07
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
  • Top
  • Article
    • ABSTRACT
    • ACKNOWLEDGMENTS
    • FOOTNOTES
    • REFERENCES
  • Figures & Data
  • Info & Metrics
  • PDF

KEYWORDS

Bacterial Typing Techniques
environmental microbiology
Staphylococcal Infections
Staphylococcus

Related Articles

Cited By...

About

  • About JCM
  • Editor in Chief
  • Board of Editors
  • Editor Conflicts of Interest
  • For Reviewers
  • For the Media
  • For Librarians
  • For Advertisers
  • Alerts
  • RSS
  • FAQ
  • Permissions
  • Journal Announcements

Authors

  • ASM Author Center
  • Submit a Manuscript
  • Article Types
  • Resources for Clinical Microbiologists
  • Ethics
  • Contact Us

Follow #JClinMicro

@ASMicrobiology

       

ASM Journals

ASM journals are the most prominent publications in the field, delivering up-to-date and authoritative coverage of both basic and clinical microbiology.

About ASM | Contact Us | Press Room

 

ASM is a member of

Scientific Society Publisher Alliance

 

American Society for Microbiology
1752 N St. NW
Washington, DC 20036
Phone: (202) 737-3600

 

Copyright © 2021 American Society for Microbiology | Privacy Policy | Website feedback

Print ISSN: 0095-1137; Online ISSN: 1098-660X