Clinical Usefulness of PCR for Differential Diagnosis of Tuberculosis and Nontuberculous Mycobacterial Infection in Paraffin-Embedded Lung Tissues

Abstract

The need for isolation of nontuberculous mycobacteria (NTM) from clinical specimens has increased in recent years. Our aim was to determine the clinical usefulness of PCR for differential diagnosis of tuberculosis and nontuberculous mycobacterial infection in lung tissue that show chronic granulomatous inflammation. A total of 199 formalin-fixed, paraffin-embedded specimens, including 137 Mycobacterium tuberculosis (MTB), 17 NTM cases, and 45 other than mycobacterial cases were collected. We performed acid-fast staining, MTB and NTM nested PCRs, and MTB and NTM real-time PCRs. No histologic difference between MTB and NTM infections was observed. Sensitivity and specificity for detecting MTB were 70.1% and 95.1% by nested PCR, respectively, and 70.8% and 100.0% by real-time PCR, respectively. Sensitivity and specificity for detecting NTM were 52.9% and 96.15% by nested PCR, respectively, and 35.3% and 100.0% by real-time PCR, respectively. Mycobacteria were identified by acid-fast staining in 50 of 154 cases (32.5%). All 50 acid-fast staining-positive cases showed positive nested and real-time PCR results (n = 47 MTB PCR positive; n = 3 NTM PCR positive), and results agreed with final diagnosis. PCR will be useful for the rapid diagnosis of mycobacterial infection and differentiation of MTB from NTM in formalin-fixed, paraffin-embedded specimens, especially in acid-fast staining-positive specimens.

Radiopathological Features and Identification of Mycobacterial Infections in Granulomatous Nodules Resected from the Lung

“…Nodule-type lesions have been reported to contain fewer mycobacteria than cavitary or consolidation lesions [25] . According to previous reports, nested PCR and real-time PCR for TB or NTM had significantly higher positivity on specimens with positive AFB staining, caseous necrosis, and calcified lesions [4,6,[24][25][26][27] . The selection of samples based on these points might be important.…”

“…One-third of the granulomas in our study were positive in nested PCR and real-time PCR of IS6110 , and 25% of those with unknown etiologies could be diagnosed. According to Kim et al [24] , nested PCR and real-time PCR had sensitivities of 70.1 and 70.8%, respectively, for detecting TB. The detection rates by both methods in our study were lower than those of previous reports [20,24] .…”

“…According to Kim et al [24] , nested PCR and real-time PCR had sensitivities of 70.1 and 70.8%, respectively, for detecting TB. The detection rates by both methods in our study were lower than those of previous reports [20,24] . The amounts of bacteria in our samples may have been too low to detect.…”

Case Report of Mycobacterium mageritense Soft Tissue Abscess in Immune Compromised Patient with Inconclusive Gram Stain and Wound Culture

“…For definitive identification of these o rg a n is m s , m o l e cu l a r m et h o d s h ave b e e n recommended 9 . Alternative diagnostic processes should be utilized in these cases, including PCR, which carries sensitivity and specificity of 52.9% and 96.2% respectively 8 . Physicians should be increasingly suspicious of rapidly growing atypical mycobacteria with any skin or soft tissue infection.…”

Comparative Characteristic of Cases of Microbacteriosis and Tuberculosis among HIV-Infected Patients

“…The problem of diagnosing the disease caused by NTMB remains unresolved due to incomplete bacteriological examination of HIVinfected patients for this pathogen because of the lack of standards for diagnosis and treatment of mycobacteriosis. Mycobacteriosis-causing NTMBs cannot be treated with anti-tuberculosis drugs despite their similar clinical and radiologic patterns with tuberculosis, which affects the results of treatment of this, often misdiagnosed, opportunistic disease [7,8,9,10,11]. At the same time, there is a problem of correct interpretation of bacteriological studies on mycobacteriosis.…”