1887

Abstract

Methicillin-resistant (MRSA) are important nosocomial pathogens. Diseases caused by these resistant bacteria frequently are serious and there is a need to control the spread of epidemic MRSA clones in hospitals. However, detection is complicated by the fact that expression of the resistance is variable and, commonly, heterogeneous within strains. The reliability of several tests recommended to discriminate heterogeneous MRSA isolates from borderline-resistant and susceptible strains was evaluated. Screening for growth on agar with methicillin 25 mg/L was the only method that detected all MRSA strains tested, but screening on agar with methicillin 10 mg/L or oxacillin 6 mg/L detected all but one of 10 heterogeneously resistant strains tested. None of the borderline-resistant nor any truly susceptible staphylococci tested grew on any of these screening plates.

Loading

Article metrics loading...

/content/journal/jmm/10.1099/00222615-46-2-145
1997-02-01
2024-12-02
Loading full text...

Full text loading...

/deliver/fulltext/jmm/46/2/medmicro-46-2-145.html?itemId=/content/journal/jmm/10.1099/00222615-46-2-145&mimeType=html&fmt=ahah

References

  1. Boyce J. M. Increasing prevalence of methicillin-resistant Staphylococcus aureus in the United States. Infect Control Hosp Epidemiol 1990; 11:639–642
    [Google Scholar]
  2. Kerr S., Kerr G. E., Mackintosh C. A., Marples R. R. A survey of methicillin-resistant Staphylococcus aureus affecting patients in England and Wales. J Hosp Infect 1990; 16:35–48
    [Google Scholar]
  3. Marques A. R., Petrillo V., Hoefel H. Methicillin-resistant Staphylococcus aureus in a general hospital in Brazil. J Hosp Infect 1989; 14:380–381
    [Google Scholar]
  4. Martin D. R., Heffernan H. M., Davis H. G. Methicillin-resistant Staphylococcus aureus: an increasing threat in New Zealand hospitals. NZ Med J 1989; 102:367–369
    [Google Scholar]
  5. Kayser F. H., Wüst J., Santanam P. Genetic and molecular characterisation of resistance determinants in methicillin-resistant Staphylococcus aureus. J Med Microbiol 1976; 9:137–148
    [Google Scholar]
  6. Kuhl S. A., Pattee P. A., Baldwin J. N. Chromosomal map location of the methicillin resistance determinant in Staphylococcus aureus. J Bacteriol 1978; 135:460–465
    [Google Scholar]
  7. Hayes M. V., Curtiss N. A. C., Wyke A. W., Ward J. B. Decreased affinity of a penicillin-binding protein for beta-lactam anti biotics in a clinical isolate of Staphylococcus aureus resistant to methicillin. FEMS Microbiol Lett 1981; 10:119–122
    [Google Scholar]
  8. Hartman B. J., Tomasz A. Expression of methicillin resistance in heterogeneous strains of Staphylococcus aureus. Antimicrob Agents Chemother 1986; 29:85–92
    [Google Scholar]
  9. Hürlimann-Delal R. L., Ryffel C., Kayser F. H., Berger-Bächi B. Survey of the methicillin resistance-associated genes mecA, mecRl-mecI, and femA-femB in clinical isolates of methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother 1992; 36:2617–2621
    [Google Scholar]
  10. de Lencastre H., Tomasz A. Reassessment of the number of auxiliary genes essential for expression of high-level methicillin resistance in Staphylococcus aureus. Antimicrob Agents Chemother 1994; 38:2590–2598
    [Google Scholar]
  11. Tomasz A., Nachman S., Leaf H. Stable classes of phenotypic expression in methicillin resistant clinical isolates of staphylococci. Antimicrob Agents Chemother 1991; 35:124–129
    [Google Scholar]
  12. de Lencastre H., Figueiredo A. M. S., Tomasz A. Genetic control of population structure in heterogeneous strains of methicillin resistant Staphylococcus aureus. Eur J Clin Microbiol Infect Dis 1993; 12: Suppl 1S13–S18
    [Google Scholar]
  13. Figueiredo A. M. S., Ha E., Kreiswith B. N. In vivo stability of heterogeneous expression classes in clinical isolates of methicillin resistant staphylococci. J Infect Dis 1991; 164:883–887
    [Google Scholar]
  14. de Lencastre H., Sà Figueiredo A. M., Urban K., Rahal J., Tomasz A. Multiple mechanisms of methicillin resistance and improved methods for detection in clinical isolates of Staphylococcus aureus. Antimicrob Agents Chemother 1991; 35:632–639
    [Google Scholar]
  15. Tomasz A., Drugeon H. B., de Lencastre H. M., Jabes D., McDougall L., Bille J. New mechanism for methicillin resistance in Staphylococcus aureus: clinical isolates that lack the PBP 2a gene and contain normal penicillin-binding proteins with modified penicillin-binding capacity. Antimicrob Agents Chemother 1989; 33:1869–1874
    [Google Scholar]
  16. Archer G. L., Pennell E. Detection of methicillin resistance in staphylococci by using a DNA probe. Antimicrob Agents Chemother 1990; 34:1720–1724
    [Google Scholar]
  17. Skulnick M., Simor A. E., Gregson D. Evaluation of commercial and standard methodology for determination of oxacillin susceptibility in Staphylococcus aureus. J Clin Microbiol 1992; 30:1985–1988
    [Google Scholar]
  18. Tokue Y., Shoji S., Satoh K., Watanabe A., Motomiya M. Comparison of a polymerase chain reaction assay and a conventional microbiological method for detection of methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother 1992; 36:6–9
    [Google Scholar]
  19. National Committee for Clinical Laboratory Standards Performance standards for antimicrobial disk susceptibility tests. 4th edn Approved standard. M2–A4 National Committee for Clinical Laboratory Standards; Villanova, PA: 1990
    [Google Scholar]
  20. National Committee for Clinical Laboratory Standards Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. 2nd edn Approved standard. M7–A2 National Committee for Clinical Laboratory Standards; Villanova, PA: 1990
    [Google Scholar]
  21. Kloos W. E., Jorgensen J. H. Staphylococci. In Balows A., Hausler W. J., Herrmann K. L., Isenberg H. D., Shadomy H. J. (eds) Manual of clinical microbiology 5th edn Washington, DC: American Society for Microbiology; 1985143–153
    [Google Scholar]
  22. Boyce J. M. Should we vigorously try to contain and control methicillin-resistant Staphylococcus aureus?. Infect Control Hosp Epidemiol 1991; 12:46–54
    [Google Scholar]
  23. Thornsberry C., McDougal L. K. Successful use of broth microdilution in susceptibility tests for methicillin-resistant (heteroresistant) staphylococci. J Clin Microbiol 1983; 18:1084–1091
    [Google Scholar]
  24. Teixeira L. A., Resende C. A., Ormonde L. R. Geographic spread of epidemic multiresistant Staphylococcus aureus clone in Brazil. J Clin Microbiol 1995; 33:2400–2404
    [Google Scholar]
/content/journal/jmm/10.1099/00222615-46-2-145
Loading
/content/journal/jmm/10.1099/00222615-46-2-145
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error