A Comparison between Polymerase Chain Reaction, Oxacillin Agar Dilusion and Cefoxitin Disk Diffusion Methods in Detection of Methicillin Resistance in Staphylococcus Aureus

Document Type : Original Article (s)

Authors

1 Associate Professor, Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

2 Assistant Professor, Nosocomial Infection Research Center AND Department of Microbiology, Isfahan University of Medical Sciences, Isfahan, Iran

3 MSc Student, Department of Microbiology, School of Medicine AND Student Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran

4 Assistant Professor, Department of Patobiology and Anatomy, School of Medicine, North Khorasan University of Medical Sciences, Bojnourd, Iran

5 Department of Microbiology, Islamic Azad University, Falavarjan Branch, Isfahan, Iran

6 PhD Student, Nosocomial Infection Research Center, Isfahan University of Medical Sciences, Isfahan, Iran

7 Epidemiologist, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

Abstract

Background: Staphylococcus aureus (S. aureus) is an important human pathogen associated with hospital- and community-acquired diseases, a wide range of infectious disease including minor skin disease to more sever and aggressive infections such as septicemia, pneumonia, endocarditis, and deep skin abscess. S. aureus has a high mortality rate of 35%. Therefore, it is crucial to identify the methicillin resistant S. aureus (MRSA) strains and implement the necessary treatment in order to control the spread of hospital infections.Methods: A total of 150 S. aureus isolates were collected from samples of patients admitted to Alzahra and Shariati hospitals in Isfahan, Iran. Polymerase chain reaction (PCR) for mecA gene was performed in all strains. Thereafter, the minimum inhibitory concentration (MIC) for oxacillin was carried out using agar dilution method. Then, antibiogram using disk diffusion for cephoxitin was performed according to Clinical and Laboratory Standards Institute (CLSI) regulations on isolates containing mecA gene. The three methods were then compared.Findings: Of the 150 samples, 62 samples (41.33%) were found to carry mecA gene using PCR. However, agar dilution for oxacillin found 56 of 62 samples (90.33%) to harbor mecA gene. Disk diffusion method revealed that 53 of 62 samples (85.48%) contain mecA gene.Conclusion: Agar dilution method was found to have a higher sensitivity in determining antibiotic sensitivity compared to disk diffusion method. However, PCR was identified as the ideal method for detecting MRSA strains; since a number of strains were found to be sensitive to oxacillin in phenotypic test due to lack of mecA expression while still containing the gene.

Keywords

References

  1. Fattom AI, Horwith G, Fuller S, Propst M, Naso R. Development of StaphVAX, a polysaccharide conjugate vaccine against S. aureus infection: from the lab bench to phase III clinical trials. Vaccine 2004; 22(7): 880-7.
  2. Wielders CL, Fluit AC, Brisse S, Verhoef J, Schmitz FJ. mecA gene is widely disseminated in Staphylococcus aureus population. J Clin Microbiol 2002; 40(11): 3970-5.
  3. Shinefield H, Black S, Fattom A, Horwith G, Rasgon S, Ordonez J, et al. Use of a Staphylococcus aureus conjugate vaccine in patients receiving hemodialysis. N Engl J Med 2002; 346(7): 491-6.
  4. Baddour MM, AbuElKheir MM, Fatani AJ. Comparison of mecA polymerase chain reaction with phenotypic methods for the detection of methicillin-resistant Staphylococcus aureus. Curr Microbiol 2007; 55(6): 473-9.
  5. Klevens RM, Edwards JR, Tenover FC, McDonald LC, Horan T, Gaynes R. Changes in the epidemiology of methicillin-resistant Staphylococcus aureus in intensive care units in US hospitals, 1992-2003. Clin Infect Dis 2006; 42(3): 389-91.
  6. Moran GJ, Amii RN, Abrahamian FM, Talan DA. Methicillin-resistant Staphylococcus aureus in community-acquired skin infections. Emerg Infect Dis 2005; 11(6): 928-30.
  7. Clinical and Laboratory Standards Institute. Protocols for evaluating dehydrated Mueller-Hinton agar- approved standard. 1st ed [Online]. 1996. Available from: URL: http://www.iso90.ir/phocadownload/csli/M06-A.pdf.
  8. Swenson JM, Spargo J, Tenover FC, Ferraro MJ. Optimal inoculation methods and quality control for the NCCLS oxacillin agar screen test for detection of oxacillin resistance in Staphylococcus aureus. J Clin Microbiol 2001; 39(10): 3781-4.
  9. Clinical and Laboratory Standards Institute. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically- approved standard. 8th ed [Online]. 2008. Available from: URL:http://www.iso90.ir/phocadownload/csli/M7-A7.pdf.
  10. Perez LR, Dias C, d'Azevedo PA. Agar dilution and agar screen with cefoxitin and oxacillin: what is known and what is unknown in detection of meticillin-resistant Staphylococcus aureus. J Med Microbiol 2008; 57(Pt 8): 954-6.
  11. Naderi Nasab M, Tavakol Afshari J, Nazem M, Fateh Manesh P, Faramarzi H, Khodadust MA. Methicillin-resistant staphylococcus aureus determined by phenotypic methods. Med J Mashad Univ Med Sc 2005; 48(1): 7-16. [In Persian].
  12. Kumar R, Yadav BR, Dev K, Singh RS. A simple protocol for DNA extraction from staphylococcus aureus [Online] 2008. Available from: URL: http://www.protocol-online. org/prot/Protocols/A-Simple-Protocol-for-DNAExtraction- from-Staphylococcus-Aureus- 4999.html.
  13. Vannuffel P, Laterre PF, Bouyer M, Gigi J, Vandercam B, Reynaert M, et al. Rapid and specific molecular identification of methicillin-resistant Staphylococcus aureus in endotracheal aspirates from mechanically ventilated patients. J Clin Microbiol 1998; 36(8): 2366-8.
  14. Holmes A, Ganner M, McGuane S, Pitt TL, Cookson BD, Kearns AM. Staphylococcus aureus isolates carrying Panton-Valentine leucocidin genes in England and Wales: frequency, characterization, and association with clinical disease. J Clin Microbiol 2005; 43(5): 2384-90.
  15. Verdier I, Durand G, Bes M, Taylor KL, Lina G, Vandenesch F, et al. Identification of the capsular polysaccharides in Staphylococcus aureus clinical isolates by PCR and agglutination tests. J Clin Microbiol 2007; 45(3): 725-9.
  16. Cekovska Z, Panovski N, Petrovska M. Methicillin-resistant Staphylococcus aureus: comparison of susceptibility test methods with mecA gene analysis for determining oxacillin (methicillin) resistance in our clinical isolates. Bratisl Lek Listy 2005; 106(4-5): 163-7.
  17. Merlino J, Watson J, Rose B, Beard-Pegler M, Gottlieb T, Bradbury R, et al. Detection and expression of methicillin/oxacillin resistance in multidrug-resistant and non-multidrug-resistant Staphylococcus aureus in Central Sydney, Australia. J Antimicrob Chemother 2002; 49(5): 793-801.
  18. Sakoulas G, Gold HS, Venkataraman L, DeGirolami PC, Eliopoulos GM, Qian Q. Methicillin-resistant Staphylococcus aureus: comparison of susceptibility testing methods and analysis of mecA-positive susceptible strains. J Clin Microbiol 2001; 39(11): 3946-51.
  19. Petinaki E, Miriagou V, Tzouvelekis LS, Pournaras S, Hatzi F, Kontos F, et al. Methicillin-resistant Staphylococcus aureus in the hospitals of central Greece. Int J Antimicrob Agents 2001; 18(1): 61-5.
  20. Wannet WJ, Spalburg E, Heck ME, Pluister GN, Willems RJ, De Neeling AJ. Widespread dissemination in The Netherlands of the epidemic berlin methicillin-resistant Staphylococcus aureus clone with low-level resistance to oxacillin. J Clin Microbiol 2004; 42(7): 3077-82.
  21. Appelbaum PC. MRSA--the tip of the iceberg. Clin Microbiol Infect 2006; 12(Suppl 2): 3-10.
  22. Adaleti R, Nakipoglu Y, Karahan ZC, Tasdemir C, Kaya F. Comparison of polymerase chain reaction and conventional methods in detecting methicillin-resistant Staphylococcus aureus. J Infect Dev Ctries 2008; 2(1): 46-50.
  23. Rahbar M, Yaghoobi M, Fattahi A. Comparison of different laboratory methods for detection of methicillin-resistant staphylococcus aureus. Pak J Med Sci 2006; 22(4): 442-5.
  24. Fatholahzadeh B, Emaneini M, Gilbert G, Udo E, Aligholi M, Modarressi MH, et al. Staphylococcal cassette chromosome mec (SCCmec) analysis and antimicrobial susceptibility patterns of methicillin-resistant Staphylococcus aureus (MRSA) isolates in Tehran, Iran. Microb Drug Resist 2008; 14(3): 217-20.
  25. Japoni A, Alborzi A, Rasoli M, Farshad S. Distribiotion patterns of methicillin resistance genes (mecA) in staphylococcus aureus isolated from clinical from specimens. Iran Biomed J 2004; 8(4): 173-8.
  26. Havaei SA, Karbalaeizadeh Babaki M, Pishva E. Comparison of the results of polymerase chain reaction and oxacillin agar dilution methods in determining resistance to methicillin in isolated staphyloccus aureus at Alzahra Hospital, Isfahan, Iran. J Isfahan Med sch 2011; 29(151): 1175-82. [In Persian].
  27. Skov R, Smyth R, Larsen AR, Bolmstrom A, Karlsson A, Mills K, et al. Phenotypic detection of methicillin resistance in Staphylococcus aureus by disk diffusion testing and Etest on Mueller-Hinton agar. J Clin Microbiol 2006; 44(12): 4395-9.
Journal of Isfahan Medical School
Volume 31, Issue 232 - Serial Number 232
March and April 2013
Pages 466-474

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History

  • Receive Date: 12 February 2013
  • Revise Date: 26 May 2024
  • Accept Date: 06 April 2022

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