This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Horvat, R. T.
Right arrow Articles by Wilson, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Horvat, R. T.
Right arrow Articles by Wilson, M.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, October 2003, p. 4611-4616, Vol. 41, No. 10
0095-1137/03/$08.00+0     DOI: 10.1128/JCM.41.10.4611-4616.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Effect of Duplicate Isolates of Methicillin-Susceptible and Methicillin-Resistant Staphylococcus aureus on Antibiogram Data

Rebecca T. Horvat,1* Neil E. Klutman,2 Melinda K. Lacy,3 Dennis Grauer,3 and Marsha Wilson4

Department of Pathology and Laboratory Medicine, University of Kansas,1 Clinical Communications, Ortho-McNeil Pharmaceuticals,2 University of Kansas School of Pharmacy,3 Clinical Laboratories, University of Kansas Medical Center Hospital, Kansas City, Kansas 661604

Received 13 March 2003/ Returned for modification 12 May 2003/ Accepted 7 July 2003

Duplicate Staphylococcus aureus isolates were analyzed to determine the impact of multiple isolates from the same patient on annual antibiogram data. During a 6-year period (1996 to 2001), 3,227 patients with 4,844 S. aureus isolates were evaluated. A total of 39% of patients with methicillin-resistant S. aureus (MRSA) (n = 860) and 23% of patients with methicillin-susceptible S. aureus (MSSA) (n = 2,367) infections had duplicate isolates. Cumulative data show that 91% of the patients during this 6-year period with duplicate isolates (2 to 13 duplicates/year) did not switch between MSSA and MRSA but retained the original S. aureus strain whether it was MSSA or MRSA. Rates of MRSA were calculated for each year by using all isolates and then eliminating duplicates. The impact of duplicate MRSA and MSSA isolates was evaluated by using the ratio of isolates per patient such that ratios of >1.0 indicate >1 isolate per patient. The 6-year ratio for MRSA was 1.90 isolates/patient, and the ratio for MSSA was 1.35. A significant difference (P < 0.05) was noted in the MRSA rates in 4 of 6 years when duplicate isolates were removed. Common phenotypic antibiogram patterns were compared for all MRSA isolates during the 6-year period, and 64% were of a single antibiogram phenotype. Eighty-eight percent of patients with duplicate MRSA isolates had phenotypically identical multiple isolates. The rate of MRSA differs when duplicate isolates are removed from the antibiogram data.

* Corresponding author. Mailing address: The University of Kansas Medical Center, Department of Pathology and Laboratory Medicine, 3901 Rainbow Blvd., Kansas City, KS 66160. Phone: (913) 588-1753. Fax: (913) 588-1777. E-mail: rhorvat{at}kumc.edu.

Journal of Clinical Microbiology, October 2003, p. 4611-4616, Vol. 41, No. 10
0095-1137/03/$08.00+0     DOI: 10.1128/JCM.41.10.4611-4616.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Kuster, S. P., Ruef, C., Zbinden, R., Gottschalk, J., Ledergerber, B., Neuber, L., Weber, R. (2008). Stratification of cumulative antibiograms in hospitals for hospital unit, specimen type, isolate sequence and duration of hospital stay. J Antimicrob Chemother 62: 1451-1461 [Abstract] [Full Text]  
  • Sundqvist, M., Kahlmeter, G. (2007). Effect of excluding duplicate isolates of Escherichia coli and Staphylococcus aureus in a 14 year consecutive database. J Antimicrob Chemother 59: 913-918 [Abstract] [Full Text]  
  • Zapantis, A., Lacy, M. K., Horvat, R. T., Grauer, D., Barnes, B. J., O'Neal, B., Couldry, R. (2005). Nationwide Antibiogram Analysis Using NCCLS M39-A Guidelines. J. Clin. Microbiol. 43: 2629-2634 [Abstract] [Full Text]  
  • Lee, S.-O., Cho, Y. K., Kim, S.-Y., Lee, E. S., Park, S. Y., Seo, Y.-H. (2004). Comparison of Trends of Resistance Rates over 3 Years Calculated from Results for All Isolates and for the First Isolate of a Given Species from a Patient. J. Clin. Microbiol. 42: 4776-4779 [Abstract] [Full Text]  
  • Magee, J. T., on behalf of the Welsh Antibiotic Study Group, (2004). Effects of duplicate and screening isolates on surveillance of community and hospital antibiotic resistance. J Antimicrob Chemother 54: 155-162 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»