Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology

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Indexed in KCI, KoreaMed, Synapse, DOAJ
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pISSN 2288-0585 eISSN 2288-6850

Clinical Usefulness of Primary Broth Cultures

Original article

Annals of Clinical Microbiology (Ann Clin Microbiol) 2000 June Volume 3, Issue 1, pages 69-74.

Clinical Usefulness of Primary Broth Cultures

Soo Jin Choi, M.D., Sang Hyun Hwang, M.D., Joon Seok Park, M.D., Mi-Na Kim, M.D. and Chik Hyun Pai, M.D.

Department of Clinical Pathology, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea

Abstract

Background: Although enriched broth cultures have been recommended as an adjuvant to the direct plating of tissue and body fluid specimens, the cost-effectiveness of broth cultures has been questioned in regard with the clinical significance of “broth only isolates (BOI)”. The purpose of this study was to investigate the usefulness of thioglycollate broth (THIO) cultures.

Methods: We reviewed retrospectively results in the culture specimens of body fluids, tissue biopsies, and puses received during the month of July 1997. All specimens were inoculated into THIO in addition to agar plates. We reviewed the medical records of culture-positive patients to determine the clinical significance and relevance of their isolates. Clinically significant isolates were defined as those for which an appropriate antimicrobial therapy was done except one judged as contaminants by clinicians and clinically relevant isolates as the clinically significant one isolated first.

Results: Of 2,008 specimens, 512 (25.4%) from 365 patients grew 561 isolates including 464 plate isolates and 97 BOI. Two hundred eighty nine (62.3%) of the 464 isolates from plate cultures were clinically significant, compared to only 12 (12.4%) of 97 BOI (P<0.05). Only four (4.1%) BOI were clinically relevant, including one Pseudomonas aeruginosa from ascites, one Klebsiella pneumoniae and two Staphylococcus aureus from tissue specimens.

Conclusion: A routine use of enriched broth culture rarely recover clinically relevant isolates. Considering the laboratory and medical costs of the recovery of contaminants and clinically irrelevant isolates, the enrichment broth cultures should be used more selectively. (Korean J Clin Microbiol 2000;3(1):69-74)

Keywords

Thioglycollate Broth Enrichment, Broth Only Isolates, Clinical Relevance