Evaluation of Propidium Monoazide Real-Time PCR for Early Detection of Viable Mycobacterium tuberculosis in Clinical Respiratory Specimens.
10.3343/alm.2014.34.3.203
- Author:
Young Jin KIM
1
;
Sun Min LEE
;
Byung Kyu PARK
;
Sung Soo KIM
;
Jongyoun YI
;
Hyung Hoi KIM
;
Eun Yup LEE
;
Chulhun Ludgerus CHANG
Author Information
1. Department of Laboratory Medicine, Pusan National University School of Medicine, Yangsan, Korea. cchl@pusan.ac.kr
- Publication Type:Original Article ; Evaluation Studies ; Research Support, Non-U.S. Gov't
- Keywords:
Mycobacterium tuberculosis;
Propidium monoazide;
Real-time PCR
- MeSH:
Adult;
Aged;
Area Under Curve;
Azides/*chemistry;
DNA, Bacterial/*analysis;
Female;
Humans;
Lung Diseases/diagnosis/*microbiology/pathology;
Male;
Middle Aged;
Mycobacterium tuberculosis/genetics/*isolation & purification;
Pilot Projects;
Propidium/*analogs & derivatives/chemistry;
ROC Curve;
*Real-Time Polymerase Chain Reaction;
Sputum/microbiology;
Tuberculosis/*diagnosis/microbiology
- From:Annals of Laboratory Medicine
2014;34(3):203-209
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND: Conventional acid-fast bacilli (AFB) staining cannot differentiate viable from dead cells. Propidium monoazide (PMA) is a photoreactive DNA-binding dye that inhibits PCR amplification by DNA modification. We evaluated whether PMA real-time PCR is suitable for the early detection of viable Mycobacterium tuberculosis (MTB) in clinical respiratory specimens. METHODS: A total of 15 diluted suspensions from 5 clinical MTB isolates were quadruplicated and subjected to PMA treatment and/or heat inactivation. Eighty-three AFB-positive sputum samples were also tested to compare the DeltaC(T) values (C(T) value in PMA-treated sputum samples-C(T) value in non-PMA-treated sputum samples) between culture-positive and culture-negative specimens. Real-time PCR was performed using Anyplex MTB/NTM Real-Time Detection (Seegene, Korea), and the C(T) value changes after PMA treatment were compared between culture-positive and culture-negative groups. RESULTS: In MTB suspensions, the increase in the C(T) value after PMA treatment was significant in dead cells (P=0.0001) but not in live cells (P=0.1070). In 14 culture-negative sputum samples, the median DeltaC(T) value was 5.3 (95% confidence interval [CI], 4.1-8.2; P<0.0001), whereas that in 69 culture-positive sputum samples was 1.1 (95% CI, 0.7-2.0). In the ROC curve analysis, the cutoff DeltaC(T) value for maximum sensitivity (89.9%) and specificity (85.7%) for differentiating dead from live cells was 3.4. CONCLUSIONS: PMA real-time PCR is a useful approach for differentiating dead from live bacilli in AFB smear-positive sputum samples.
