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

6

Weeks in Review

4

Weeks to Publication
Indexed in KCI, KoreaMed, Synapse, DOAJ
Open Access, Peer Reviewed
pISSN 2288-0585 eISSN 2288-6850
Original article

Investigation of Positive Streptococcus pneumoniae Urinary Antigen Test Results in a Korean University Hospital

In-Suk Kim1, Eun-Ha Koh1, Sunjoo Kim1, Kook Young Maeng1, Hyun Ju Jung2

Department of Laboratory Medicine, Institute of Health Sciences, 1Gyeongsang National University School of Medicine, Jinju, 2Masan Medical Center, Masan, Korea

Corresponding to Sunjoo Kim, E-mail: sjkim8239@hanmail.net

Ann Clin Microbiol 2010;13(1):14-18. https://doi.org/10.5145/KJCM.2010.13.1.14
Copyright © Korean Society of Clinical Microbiology.

Abstract

Background: The Streptococcus pneumoniae urinary antigen test (SPUAT) (Binax Now, USA) was developed for detecting polysaccharide C in urine samples for rapid diagnosis of pneumococcal pneumonia, the most common cause of community-acquired pneumonia (CAP). To validate positive results of these tests, we retrospectively investigated all positive results obtained from the emergency room of a Korean university hospital among patients with suspected CAP. 

Methods: One hundred twenty-three positive SPUAT results were abstracted and analyzed from the authors’ laboratory information system among the SPUAT results performed from 1,143 pneumonic patients admitted from the emergency room of a university hospital between 2007 and 2008. Medical records, including conventional microbiologic analysis results, were reviewed in detail for all positive test results. 

Results: Among 123 patients with the positive SPUAT results, 24 patients were excluded due to hospitalization history during the preceding month. Nine of 99 patients (9.1%) with suspected CAP had confirmed pneumococcal pneumonia upon conventional sputum or blood culture. Thirty-five positive results (35.4%) showed other microorganisms upon conventional methods, which might be due to possible cross-reactivity. Among those, 23 positive results were considered bacterial pneumonic agents, and 12 positive results were regarded as urinary tract infection strains or contaminating agents. Fifty-five positive SPUAT results (55.6%) showed negative conventional microbiologic growth, and some positive SPUAT results might be caused by true pneumococcal infection although without cultural evidence. 

Conclusion: Our retrospective study demonstrated that a positive SPUAT result typically does not agree well with conventional culture methods, suggesting that the value of a positive SPUAT result in etiology determination may be limited under practical conditions in a university hospital. (Korean J Clin Microbiol 2010;13:14-18)

Keywords

Streptococcus pneumoniae, Bacterial antigens, Urinary antigen test, Cross-reactivity