A comparative study to determine the recovery rate of micro-organisms of bloodstream infections: two versus three blood culture specimens

Abstract number: P1772

Shanthachol T., Suwanpimolkul G., Suankratay C.

Background: There has been the development of automated and continuous-monitoring blood culture system which is more sensitive for the detection of microorganisms. Whether two or three blood cultures obtained during a 24-hour period using this automated system achieving a higher recovery rate of microorganism remains to be determined. Our study was aimed to compare the recovery rate of microorganism of blood-stream infections using two and three blood culture specimens.

Methods: A prospectively investigator-blinded study was conducted in patients who needed to have blood cultures in Medicine wards and intensive care units as well as emergency room of King Chulalongkorn Memorial Hospital, Bangkok, Thailand between September 2008 and January 2009. Three blood culture specimens were obtained from each patient during a 24-hour period. Each specimen was inoculated into an aerobic bottle of blood culture broth (Trek Diagnostic Systems, Cleveland, OH, USA), and then was incubated at 37OC for 7 days.

Results: Of 210 patients, there were 48 (22.85%) unimicrobial episodes with 3 blood cultures obtained during a 24-hour period. There were 30 (14.28%) and 18 (8.5%) episodes of true pathogen and contaminant, respectively. Nineteen (63.3%), 21 (70%), and 30 (100%) were detected with the first one, two, and three blood culture specimens, respectively (P < 0.05 between the recovery rate of the first two and three blood culture specimens). There were 21 (43.75%) and 30 (62.5%) episodes of true pathogen detected with the first two and three blood culture specimens, respectively. There were 33 (68.75%) and 15 (31.25%) isolates of Gram-positive and Gram-negative bacteria. Among 33 Gram-positive bacteria, Streptococcus pneumoniae was the most common isolate (5, 15.2%), followed by coagulase-negative Staphylococcus (4, 12.1%) and Enterococcus faecalis (3, 9.1%). Among 15 Gram-negative bacteria, Escherichia coli was the most common isolate (5, 33.3%), followed by Pseudomonas aeruginosa (4, 26.7%) and Klebsiella pneumoniae (3, 20%).

Conclusions: To the best of our knowledge, our study is the first in Asia to determine the recovery rate of microorganisms of blood-stream infections using the automated blood culture system. Three blood culture specimens are required to achieve the recovery rate of more than 99%.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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