Korean J Clin Microbiol.  2009 Jun;12(2):67-71. 10.5145/KJCM.2009.12.2.67.

Comparison of Two Sputum Processing Methods for Detecting Mycobacterium tuberculosis by Culture and PCR: Universal Sample Processing (USP) and NALC-NaOH Methods

• Yun HK
• Kim SH
• Cho D
• Kee SJ
• Shin MG
• Shin JH
• Suh SP
• Ryang DW

• KMID: 1469955
• DOI: http://doi.org/10.5145/KJCM.2009.12.2.67

Abstract

BACKGROUND: The universal sample processing (USP) method has recently been introduced as a simple technique that is applicable to smear microscopy, culture, and polymerase chain reaction (PCR) for the detection of Mycobaterium tuberculosis (MTB). The present study evaluated the utility of the USP method for detecting MTB by culture and PCR, and the results were compared with that of the N-acetyl L-cysteine (NALC)-NaOH (6%) method.
METHODS
All sputum specimens were digested and decontaminated by both the USP and NALC-NaOH methods, and the processed samples were inoculated for MTB culture and PCR. Culture was performed (252 samples) by using the MGIT system (Becton Dickinson Microbiology Systems, Sparks, Md, USA), and PCR test was conducted (281 samples) by using Amplicor MTB kit (Roche Molecular Systems, Branchburg, N.J., USA).
RESULTS
MTB culture positive rates by NALC-NaOH and USP methods were 13.5% (34/252) and 11.9% (30/252), respectively (P>0.05). There were no significant differences between the two methods for detecting MTB by PCR: the MTB PCR sensitivities by USP and NALC-NaOH methods were 77.8% (49/63) and 82.5% (52/63), respectively, and the specificities were 95.9% (209/218) and 96.3% (210/218), respectively (P>0.05).
CONCLUSION
There were no significant differences between USP and NALC-NaOH methods of sample processing in enhancing the detection of MTB by culture or PCR

Keyword

Mycobacterium tuberculosis; NALC-NaOH; MGIT; PCR

MeSH Terms

Collodion
Cysteine
Microscopy
Mycobacterium
Mycobacterium tuberculosis
Polymerase Chain Reaction
Sputum
Tuberculosis
Collodion
Cysteine