Skip to main content
PMC home page
Journal of Clinical Microbiology logoLink to Journal of Clinical Microbiology
. 1995 Oct;33(10):2723–2727. doi: 10.1128/jcm.33.10.2723-2727.1995

Comparison of MIDI Sherlock system and pulsed-field gel electrophoresis in characterizing strains of methicillin-resistant Staphylococcus aureus from a recent hospital outbreak.

R B Leonard 1, J Mayer 1, M Sasser 1, M L Woods 1, B R Mooney 1, B G Brinton 1, P L Newcomb-Gayman 1, K C Carroll 1
PMCID: PMC228563  PMID: 8567913

Abstract

An outbreak of methicillin-resistant Staphylococcus aureus infections at the University of Utah Health Sciences Center occurred over a 7-month period. While the isolates phenotypically appeared to be similar in gross morphology and have similar Vitek antibiotic susceptibility patterns, two additional methods of strain characterization were evaluated to enhance the epidemiological investigation: pulsed-field gel electrophoresis and gas chromatography with the MIDI Sherlock system. Sherlock uses gas chromatography to qualitatively and quantitatively analyze the cellular fatty acid composition of organisms and creates two-dimensional plots based on principal-component analysis to define groups of closely related organisms. All isolates were also evaluated by digesting their chromosomal DNAs with the low-frequency-cutting enzyme SmaI and separating the restriction fragments by contour-clamped homogeneous electric field gel electrophoresis. Sample preparation for this pulsed-field gel electrophoresis included a novel cell lysis procedure involving achromopeptidase, greatly reducing the turnaround time. Isolates tested were recovered from the following: 45 suspected outbreak patients, 6 hospitalized patients believed to be unrelated to the outbreak, 6 patients from outside the hospital, and one health care practitioner implicated in the outbreak. Of 45 phenotypically similar suspect strains, 43 clustered tightly on the Sherlock two-dimensional plot. All outbreak patient isolates were also identical by pulsed-field gel electrophoresis with the exception of the same two outliers identified by Sherlock. In this epidemiologic investigation, we found an excellent correlation between the Sherlock and pulsed-field gel electrophoresis results for strain characterization of methicillin-resistant S. aureus.

Full Text

The Full Text of this article is available as a PDF (271.9 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Birnbaum D., Herwaldt L., Low D. E., Noble M., Pfaller M., Sherertz R., Chow A. W. Efficacy of microbial identification system for epidemiologic typing of coagulase-negative staphylococci. J Clin Microbiol. 1994 Sep;32(9):2113–2119. doi: 10.1128/jcm.32.9.2113-2119.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Branchini M. L., Morthland V. H., Tresoldi A. T., Von Nowakonsky A., Dias M. B., Pfaller M. A. Application of genomic DNA subtyping by pulsed field gel electrophoresis and restriction enzyme analysis of plasmid DNA to characterize methicillin-resistant Staphylococcus aureus from two nosocomial outbreaks. Diagn Microbiol Infect Dis. 1993 Nov-Dec;17(4):275–281. doi: 10.1016/0732-8893(93)90036-7. [DOI] [PubMed] [Google Scholar]
  3. Coyle M. B., Leonard R. B., Nowowiejski D. J., Malekniazi A., Finn D. J. Evidence of multiple taxa within commercially available reference strains of Corynebacterium xerosis. J Clin Microbiol. 1993 Jul;31(7):1788–1793. doi: 10.1128/jcm.31.7.1788-1793.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. George C. G., Kloos W. E. Comparison of the SmaI-digested chromosomes of Staphylococcus epidermidis and the closely related species Staphylococcus capitis and Staphylococcus caprae. Int J Syst Bacteriol. 1994 Jul;44(3):404–409. doi: 10.1099/00207713-44-3-404. [DOI] [PubMed] [Google Scholar]
  5. Goering R. V., Winters M. A. Rapid method for epidemiological evaluation of gram-positive cocci by field inversion gel electrophoresis. J Clin Microbiol. 1992 Mar;30(3):577–580. doi: 10.1128/jcm.30.3.577-580.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Goh S. H., Byrne S. K., Zhang J. L., Chow A. W. Molecular typing of Staphylococcus aureus on the basis of coagulase gene polymorphisms. J Clin Microbiol. 1992 Jul;30(7):1642–1645. doi: 10.1128/jcm.30.7.1642-1645.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Ichiyama S., Ohta M., Shimokata K., Kato N., Takeuchi J. Genomic DNA fingerprinting by pulsed-field gel electrophoresis as an epidemiological marker for study of nosocomial infections caused by methicillin-resistant Staphylococcus aureus. J Clin Microbiol. 1991 Dec;29(12):2690–2695. doi: 10.1128/jcm.29.12.2690-2695.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Kotilainen P., Huovinen P., Eerola E. Application of gas-liquid chromatographic analysis of cellular fatty acids for species identification and typing of coagulase-negative staphylococci. J Clin Microbiol. 1991 Feb;29(2):315–322. doi: 10.1128/jcm.29.2.315-322.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Kreiswirth B., Kornblum J., Arbeit R. D., Eisner W., Maslow J. N., McGeer A., Low D. E., Novick R. P. Evidence for a clonal origin of methicillin resistance in Staphylococcus aureus. Science. 1993 Jan 8;259(5092):227–230. doi: 10.1126/science.8093647. [DOI] [PubMed] [Google Scholar]
  10. Leonard R. B., Nowowiejski D. J., Warren J. J., Finn D. J., Coyle M. B. Molecular evidence of person-to-person transmission of a pigmented strain of Corynebacterium striatum in intensive care units. J Clin Microbiol. 1994 Jan;32(1):164–169. doi: 10.1128/jcm.32.1.164-169.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Locksley R. M., Cohen M. L., Quinn T. C., Tompkins L. S., Coyle M. B., Kirihara J. M., Counts G. W. Multiply antibiotic-resistant Staphylococcus aureus: introduction, transmission, and evolution of nosocomial infection. Ann Intern Med. 1982 Sep;97(3):317–324. doi: 10.7326/0003-4819-97-3-317. [DOI] [PubMed] [Google Scholar]
  12. Martin M. A. Methicillin-resistant Staphylococcus aureus: the persistent resistant nosocomial pathogen. Curr Clin Top Infect Dis. 1994;14:170–191. [PubMed] [Google Scholar]
  13. Maslow J. N., Mulligan M. E., Arbeit R. D. Molecular epidemiology: application of contemporary techniques to the typing of microorganisms. Clin Infect Dis. 1993 Aug;17(2):153–164. doi: 10.1093/clinids/17.2.153. [DOI] [PubMed] [Google Scholar]
  14. Miller L. T. Single derivatization method for routine analysis of bacterial whole-cell fatty acid methyl esters, including hydroxy acids. J Clin Microbiol. 1982 Sep;16(3):584–586. doi: 10.1128/jcm.16.3.584-586.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Mukwaya G. M., Welch D. F. Subgrouping of Pseudomonas cepacia by cellular fatty acid composition. J Clin Microbiol. 1989 Dec;27(12):2640–2646. doi: 10.1128/jcm.27.12.2640-2646.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Prevost G., Jaulhac B., Piemont Y. DNA fingerprinting by pulsed-field gel electrophoresis is more effective than ribotyping in distinguishing among methicillin-resistant Staphylococcus aureus isolates. J Clin Microbiol. 1992 Apr;30(4):967–973. doi: 10.1128/jcm.30.4.967-973.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Saulnier P., Bourneix C., Prévost G., Andremont A. Random amplified polymorphic DNA assay is less discriminant than pulsed-field gel electrophoresis for typing strains of methicillin-resistant Staphylococcus aureus. J Clin Microbiol. 1993 Apr;31(4):982–985. doi: 10.1128/jcm.31.4.982-985.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Schlichting C., Branger C., Fournier J. M., Witte W., Boutonnier A., Wolz C., Goullet P., Döring G. Typing of Staphylococcus aureus by pulsed-field gel electrophoresis, zymotyping, capsular typing, and phage typing: resolution of clonal relationships. J Clin Microbiol. 1993 Feb;31(2):227–232. doi: 10.1128/jcm.31.2.227-232.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Slifkin M., Cumbie R. Serogrouping single colonies of beta-hemolytic streptococci with achromopeptidase extraction. J Clin Microbiol. 1987 Aug;25(8):1555–1556. doi: 10.1128/jcm.25.8.1555-1556.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Stoakes L., John M. A., Lannigan R., Schieven B. C., Ramos M., Harley D., Hussain Z. Gas-liquid chromatography of cellular fatty acids for identification of staphylococci. J Clin Microbiol. 1994 Aug;32(8):1908–1910. doi: 10.1128/jcm.32.8.1908-1910.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Struelens M. J., Bax R., Deplano A., Quint W. G., Van Belkum A. Concordant clonal delineation of methicillin-resistant Staphylococcus aureus by macrorestriction analysis and polymerase chain reaction genome fingerprinting. J Clin Microbiol. 1993 Aug;31(8):1964–1970. doi: 10.1128/jcm.31.8.1964-1970.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Tenover F. C., Arbeit R., Archer G., Biddle J., Byrne S., Goering R., Hancock G., Hébert G. A., Hill B., Hollis R. Comparison of traditional and molecular methods of typing isolates of Staphylococcus aureus. J Clin Microbiol. 1994 Feb;32(2):407–415. doi: 10.1128/jcm.32.2.407-415.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Versalovic J., Woods C. R., Jr, Georghiou P. R., Hamill R. J., Lupski J. R. DNA-based identification and epidemiologic typing of bacterial pathogens. Arch Pathol Lab Med. 1993 Nov;117(11):1088–1098. [PubMed] [Google Scholar]
  24. Welch D. F. Applications of cellular fatty acid analysis. Clin Microbiol Rev. 1991 Oct;4(4):422–438. doi: 10.1128/cmr.4.4.422. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Journal of Clinical Microbiology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES