Rapid detection of mycobacterium tuberculosis complex by real-time polymerase chain reaction (PCR) in pulmonary and extra-pulmonary samples in Casablanca, Morocco

Abstract

Introduction the laboratory diagnosis of tuberculosis (TB) relies mainly on conventional techniques. However, it either lacks sensitivity or it is time-consuming. This study aims to evaluate the use of real-time polymerase chain reaction (PCR) targeting IS6110 for Mycobacterium tuberculosis (TB) Complex (MTBC) in the routine diagnosis of TB in our laboratory. Methods clinical samples were collected from the laboratory of bacteriology at Ibn Rochd University Hospital in Casablanca Morocco. Real-time polymerase chain reaction (PCR) results were compared to AFB smear and culture on Löwenstein-Jensen (LJ) solid media. Sensitivity, specificity, positive and negative predictive value (PPV and NPV) with 95% confidence intervals were calculated using GraphPad Prism. Results on 171 clinical samples, the study showed positivity of microscopy, culture and real-time PCR for M. TB complex as 19%, 31%, and 32% respectively. Sensitivity, specificity, PPV and NPV for real-time PCR in pulmonary samples were 95.2%, 95.4%, 90.91% and 97.65% respectively. For extra-pulmonary samples, they were: 72.7%, 90.32%, 72.7%, and 90.3%. Conclusion our study shows the effectiveness of using real-time PCR IS6110 in pulmonary and extra pulmonary samples. Future multicentric studies could seek to evaluate the place of this technique on routine diagnosis for better management of TB in Morocco.

Use of Gene Xpert MTB/Rif Assay for Detecting Mycobacterium Tuberculosis and Rifampicin Resistance

“…Other studies reported the assay's sensitivity for detecting rifampicin resistance to be 95% -100%. Specificity was 99%-100% (Fakhreddine et al, 2020;Penn-Nicholson et al, 2021). In the current study, MTB/RIF assay showed 79 samples were RIFsusceptible, and 1 was RIF-resistant.…”

A clinical case and a review of Mycobacterium fortuitum infections direct diagnosis approach and treatment in a patient with leg fractures

“…The colonies were initially identified by Acid-Faststain [14]. We performed a real-time polymerase chain reaction (PCR) of Mycobacterium tuberculosis for Acid-Fast stainpositive colonies [15] and found that the bacteria were not Mycobacterium tuberculosis. Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), the colonies were identified as M. fortuitum.…”