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 Søgaard, M.
Right arrow Articles by Schønheyder, H. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Søgaard, M.
Right arrow Articles by Schønheyder, H. C.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, April 2007, p. 1113-1117, Vol. 45, No. 4
0095-1137/07/$08.00+0     doi:10.1128/JCM.02523-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

First Notification of Positive Blood Cultures and the High Accuracy of the Gram Stain Report{triangledown}

Mette Søgaard,1,2* Mette Nørgaard,2 and Henrik C. Schønheyder1

Department of Clinical Microbiology, Aalborg Hospital, Aarhus University Hospital,1 Department of Clinical Epidemiology, Aarhus University Hospital, Aalborg, Denmark2

Received 18 December 2006/ Returned for modification 8 January 2007/ Accepted 6 February 2007

When blood cultures turn positive, the attending physicians are usually notified immediately about Gram stain findings. However, information on the accuracy of Gram staining is very limited. We examined the accuracy of preliminary blood culture reports provided by a regional laboratory in an observational study including the years 1996, 2000 to 2001, and 2003. We used data from computer files and technicians' laboratory notes. The study was restricted to cultures with one morphological type. Using cultural identification as a reference, we estimated the sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) for the following defined morphological groups: gram-positive cocci in clusters, gram-positive cocci in chains or diplococci, gram-positive rods, gram-negative cocci, gram-negative rods, and yeasts. We further evaluated the Gram stain and wet mount findings for the most frequent bacterial species/groups. We obtained 5,893 positive blood cultures and the following results for the defined groups: sensitivity, range of 91.3 to 99.7%; specificity, 98.9 to 100%; PPV, 94.6 to 100%; and NPV, 99.0 to 100%. The sensitivity for the most frequent species was in the range 91.3 to 100%, with nonhemolytic streptococci having the lowest value (sensitivity, 91.3%; 95% confidence interval, 86.2 to 94.9%). Wet mount reports were less accurate (sensitivity of 30 to 70% for species with peritrichous motility), and Enterobacteriaceae (notably Salmonella spp.) accounted for 25% of the reports stating polar motility. In conclusion, we demonstrated a high accuracy of Gram stain reports, whereas wet mount microscopy was generally less accurate.

* Corresponding author. Mailing address: Department of Clinical Epidemiology, Sdr. Skovvej 15, Post Box 365, 9100 Aalborg, Denmark. Phone: 45 99 32 69 00. Fax: 45 99 32 69 14. E-mail: mette.soegaard{at}rn.dk

{triangledown} Published ahead of print on 14 February 2007.

Journal of Clinical Microbiology, April 2007, p. 1113-1117, Vol. 45, No. 4
0095-1137/07/$08.00+0     doi:10.1128/JCM.02523-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Uehara, Y., Yagoshi, M., Tanimichi, Y., Yamada, H., Shimoguchi, K., Yamamoto, S., Yanai, M., Kumasaka, K. (2009). Impact of Reporting Gram Stain Results From Blood Culture Bottles on the Selection of Antimicrobial Agents. Am J Clin Pathol 132: 18-25 [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»