Research article

Data correction pre-processing for electronically stored blood culture results: Implications on microbial spectrum and empiric antibiotic therapy

Ojan Assadian¹ , Magda Diab-Elschahawi¹ , Athanasios Makristathis² , Alexander Blacky¹ , Walter Koller¹ and Klaus-Peter Adlassnig^3,4

¹Clinical Institute for Hygiene and Medical Microbiology, Medical University of Vienna, Division of Hospital Hygiene, Waehringer Guertel 18-20, A-1090 Vienna, Austria

²Clinical Institute for Hygiene and Medical Microbiology, Medical University of Vienna, Division of Clinical Microbiology, Waehringer Guertel 18-20, A-1090 Vienna, Austria

³Section on Medical Expert and Knowledge-Based Systems, Medical University of Vienna, Spitalgasse 23, A-1090 Vienna, Austria

⁴Medexter Healthcare GmbH, Borschkegasse 7/5, A-1090 Vienna, Austria

author email corresponding author email

BMC Medical Informatics and Decision Making 2009, 9:27doi:10.1186/1472-6947-9-27

Published:	7 June 2009

Abstract

Background

The outcome of patients with bacteraemia is influenced by the initial selection of adequate antimicrobial therapy. The objective of our study was to clarify the influence of different crude data correction methods on a) microbial spectrum and ranking of pathogens, and b) cumulative antimicrobial susceptibility pattern of blood culture isolates obtained from patients from intensive care units (ICUs) using a computer based tool, MONI.

Methods

Analysis of 13 ICUs over a period of 7 years yielded 1427 microorganisms from positive results. Three different data correction methods were applied. Raw data method (RDM): Data without further correction, including all positive blood culture results. Duplicate-free method (DFM): Correction of raw data for consecutive patient's results yielding same microorganism with similar antibiogram within a two-week period. Contaminant-free method (CFM): Bacteraemia caused by possible contaminants was only assumed as true bloodstream infection, if an organism of the same species was isolated from > 2 sets of blood cultures within 5 days.

Results

Our study demonstrates that different approaches towards raw data correction – none (RDM), duplicate-free (DFM), and a contaminant-free method (CFM) – show different results in analysis of positive blood cultures. Regarding the spectrum of microorganisms, RDM and DFM yielded almost similar results in ranking of microorganisms, whereas using the CFM resulted in a clinically and epidemiologically more plausible spectrum.

Conclusion

For possible skin contaminants, the proportion of microorganisms in terms of number of episodes is most influenced by the CFM, followed by the DFM. However, with exception of fusidic acid for gram-positive organisms, none of the evaluated correction methods would have changed advice for empiric therapy on the selected ICUs.