MRSA detection: comparison of two molecular methods (BD GeneOhm® PCR assay and Easy-Plex) with two selective MRSA agars (MRSA-ID and Oxoid MRSA) for nasal swabs

  • S. J. van Hal
  • Z. Jennings
  • D. Stark
  • D. Marriott
  • J. Harkness
Article

Abstract

Screening of patients is an important component for methicillin-resistant Staphylococcus aureus (MRSA) containment. The aim of this study was to determine the utility of molecular methods compared to selective agars for MRSA detection. Consecutive high risk patients (n = 200) were screened for nasal MRSA colonization using chromogenic selective agars (MRSA ID and CMRSA) as well as the BD GeneOhm MRSA (previously known as IDI-MRSA) and the Easy-Plex commercial real time PCR assays. The sensitivities of the molecular methods were similar to the BD GeneOhm MRSA (86%) and Easy-Plex (84%). The chromogenic agars, MRSA ID and CMRSA, showed sensitivities of 62% and 84%, respectively. Sensitivity was influenced by both the MRSA antibiograms and MRSA clonal type. The specificity was >98% in all methods except for the Easy-Plex assay (90%). Sensitivity of selective agars increased with 48 hours of incubation with a corresponding decrease in specificity. In conclusion, molecular detection methods for MRSA remain sensitive and rapid but are associated with greater expense.

References

  1. 1.
    Nimmo GR, Coombs GW, Pearson JC, O’Brien FG, Christiansen KJ, Turnidge JD et al (2006) Methicillin-resistant Staphylococcus aureus in the Australian community: an evolving epidemic. Med J Aust 184(8):384–388PubMedGoogle Scholar
  2. 2.
    Nimmo GR, Pearson JC, Collignon PJ, Christiansen KJ, Coombs GW, Bell JM et al (2007) Prevalence of MRSA among Staphylococcus aureus isolated from hospital inpatients, 2005: report from the Australian Group for Antimicrobial Resistance. Commun Dis Intell 31(3):288–296PubMedGoogle Scholar
  3. 3.
    Fridkin SK, Hageman JC, Morrison M, Sanza LT, Como-Sabetti K, Jernigan JA et al (2005) Methicillin-resistant Staphylococcus aureus disease in three communities. N Engl J Med 352(14):1436–1444. doi:10.1056/NEJMoa043252 PubMedCrossRefGoogle Scholar
  4. 4.
    Kim SH, Park WB, Lee KD, Kang CI, Kim HB, Oh MD et al (2003) Outcome of Staphylococcus aureus bacteremia in patients with eradicable foci versus noneradicable foci. Clin Infect Dis 37(6):794–799. doi:10.1086/377540 PubMedCrossRefGoogle Scholar
  5. 5.
    Lodise TP, McKinnon PS (2005) Clinical and economic impact of methicillin resistance in patients with Staphylococcus aureus bacteremia. Diagn Microbiol Infect Dis 52(2):113–122. doi:10.1016/j.diagmicrobio.2005.02.007 PubMedCrossRefGoogle Scholar
  6. 6.
    Wernitz MH, Swidsinski S, Weist K, Sohr D, Witte W, Franke KP et al (2005) Effectiveness of a hospital-wide selective screening programme for methicillin-resistant Staphylococcus aureus (MRSA) carriers at hospital admission to prevent hospital-acquired MRSA infections. Clin Microbiol Infect 11(6):457–465. doi:10.1111/j.1469–0691.2005.01152.x PubMedCrossRefGoogle Scholar
  7. 7.
    Jernigan JA, Titus MG, Groschel DH, Getchell-White S, Farr BM (1996) Effectiveness of contact isolation during a hospital outbreak of methicillin-resistant Staphylococcus aureus. Am J Epidemiol 143(5):496–504PubMedGoogle Scholar
  8. 8.
    Keene A, Vavagiakis P, Lee MH, Finnerty K, Nicolls D, Cespedes C et al (2005) Staphylococcus aureus colonization and the risk of infection in critically ill patients. Infect Control Hosp Epidemiol 26(7):622–628. doi:10.1086/502591 PubMedCrossRefGoogle Scholar
  9. 9.
    Oztoprak N, Cevik MA, Akinci E, Korkmaz M, Erbay A, Eren SS et al (2006) Risk factors for ICU-acquired methicillin-resistant Staphylococcus aureus infections. Am J Infect Control 34(1):1–5. doi:10.1016/j.ajic.2005.07.005 PubMedCrossRefGoogle Scholar
  10. 10.
    National Committee for Clinical Laboratory Standards (2005) Performance standards for antimicrobial susceptibility testing; fifteenth informational supplement, M2-A8 and M7-A6, Wayne, PAGoogle Scholar
  11. 11.
    Gosbell IB, Neville SA, Mercer JL, Fernandes LA, Fernandes CJ (2003) Detection of intrinsic oxacillin resistance in non-multiresistant, oxacillin-resistant Staphylococcus aureus (NORSA). J Antimicrob Chemother 51(2):468–470. doi:10.1093/jac/dkg064 PubMedCrossRefGoogle Scholar
  12. 12.
    Huletsky A, Lebel P, Picard FJ, Bernier M, Gagnon M, Boucher N et al (2005) Identification of methicillin-resistant Staphylococcus aureus carriage in less than 1 hour during a hospital surveillance program. Clin Infect Dis 40(7):976–981. doi:10.1086/428579 PubMedCrossRefGoogle Scholar
  13. 13.
    Warren DK, Liao RS, Merz LR, Eveland M, Dunne WM Jr (2004) Detection of methicillin-resistant Staphylococcus aureus directly from nasal swab specimens by a real-time PCR assay. J Clin Microbiol 42(12):5578–5581. doi:10.1128/JCM.42.12.5578-5581 PubMedCrossRefGoogle Scholar
  14. 14.
    Heusser R, Ender M, Berger-Bachi B, McCallum N (2007) Mosaic staphylococcal cassette chromosome mec containing two recombinase loci and a new mec complex, B2. Antimicrob Agents Chemother 51(1):390–393. doi:10.1128/AAC.00921-06 PubMedCrossRefGoogle Scholar
  15. 15.
    Kondo Y, Ito T, Ma XX, Watanabe S, Kreiswirth BN, Etienne J et al (2007) Combination of multiplex PCRs for staphylococcal cassette chromosome mec type assignment: rapid identification system for mec, ccr, and major differences in junkyard regions. Antimicrob Agents Chemother 51(1):264–274. doi:10.1128/AAC.00165-06 PubMedCrossRefGoogle Scholar
  16. 16.
    Desjardins M, Guibord C, Lalonde B, Toye B, Ramotar K (2006) Evaluation of the IDI-MRSA assay for detection of methicillin-resistant Staphylococcus aureus from nasal and rectal specimens pooled in a selective broth. J Clin Microbiol 44(4):1219–1223. doi:10.1128/JCM.44.4.1219-1223.2006 PubMedCrossRefGoogle Scholar
  17. 17.
    Huletsky A, Giroux R, Rossbach V, Gagnon M, Vaillancourt M, Bernier M et al (2004) New real-time PCR assay for rapid detection of methicillin-resistant Staphylococcus aureus directly from specimens containing a mixture of staphylococci. J Clin Microbiol 42(5):1875–1884. doi:10.1128/JCM.42.5.1875-1884.2004 PubMedCrossRefGoogle Scholar
  18. 18.
    Boyce JM, Havill NL (2008) Comparison of BD GeneOhm methicillin-resistant Staphylococcus aureus (MRSA) PCR versus the CHROMagar MRSA assay for screening patients for the presence of MRSA strains. J Clin Microbiol 46(1):350–351. doi:10.1128/JCM.02130-07 PubMedCrossRefGoogle Scholar
  19. 19.
    Malhotra-Kumar S, Haccuria K, Michiels M, Ieven M, Poyart C, Hryniewicz W et al (2008) Current trends in rapid diagnostics for methicillin-resistant Staphylococcus aureus and glycopeptide-resistant enterococcus species. J Clin Microbiol 46(5):1577–1587. doi:10.1128/JCM.00326-08 PubMedCrossRefGoogle Scholar
  20. 20.
    Paule SM, Hacek DM, Kufner B, Truchon K, Thomson RB Jr, Kaul KL et al (2007) Performance of the BD GeneOhm methicillin-resistant Staphylococcus aureus test before and during high-volume clinical use. J Clin Microbiol 45(9):2993–2998. doi:10.1128/JCM.00670-07 PubMedCrossRefGoogle Scholar
  21. 21.
    Farley JE, Stamper PD, Ross T, Cai M, Speser S, Carroll KC (2008) Comparison of the BD GeneOhm methicillin-resistant Staphylococcus aureus (MRSA) PCR assay to culture by use of BBL CHROMagar MRSA for detection of MRSA in nasal surveillance cultures from an at-risk community population. J Clin Microbiol 46(2):743–746. doi:10.1128/JCM.02071-07 PubMedCrossRefGoogle Scholar
  22. 22.
    Francois P, Bento M, Renzi G, Harbarth S, Pittet D, Schrenzel J (2007) Evaluation of three molecular assays for rapid identification of methicillin-resistant Staphylococcus aureus. J Clin Microbiol 45(6):2011–2013. doi:10.1128/JCM.00232-07 PubMedCrossRefGoogle Scholar
  23. 23.
    van Hal SJ, Stark D, Lockwood B, Marriott D, Harkness J (2007) Methicillin-resistant Staphylococcus aureus (MRSA) detection: comparison of two molecular methods (IDI-MRSA PCR assay and GenoType MRSA Direct PCR assay) with three selective MRSA agars (MRSA ID, MRSASelect, and CHROMagar MRSA) for use with infection-control swabs. J Clin Microbiol 45(8):2486–2490. doi:10.1128/JCM.00139-07 PubMedCrossRefGoogle Scholar
  24. 24.
    Diederen BM, van Leest ML, van Duijn I, Willemse P, van Keulen PH, Kluytmans JA (2006) Performance of MRSA ID, a new chromogenic medium for detection of methicillin-resistant Staphylococcus aureus. J Clin Microbiol 44(2):586–588. doi:10.1128/JCM.44.2.586-588.2006 PubMedCrossRefGoogle Scholar
  25. 25.
    Wernitz MH, Keck S, Swidsinski S, Schulz S, Veit SK (2005) Cost analysis of a hospital-wide selective screening programme for methicillin-resistant Staphylococcus aureus (MRSA) carriers in the context of diagnosis related groups (DRG) payment. Clin Microbiol Infect 11(6):466–471. doi:10.1111/j.1469-0691.2005.01153.x PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • S. J. van Hal
    • 1
  • Z. Jennings
    • 1
  • D. Stark
    • 1
  • D. Marriott
    • 1
  • J. Harkness
    • 1
  1. 1.Department of Microbiology and Infectious DiseasesSt.Vincent’s HospitalDarlinghurstAustralia

Personalised recommendations