Prevalence of Multidrug-Resistant Tuberculosis Using Phenotypic Drug Susceptibility Testing and GeneXpert MTB/RIF with Characterization of Non-tuberculous Mycobacteria Using MALDI-TOF

Document Type : New and original researches in the field of Microbiology.

Author

Lecturer of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Egypt.

Abstract

Background: Multidrug-resistant tuberculosis (MDR-TB) and infections by non-tuberculous mycobacteria (NTM) are diseases of major public health concern. Objective:  The aim of the present work is to study the prevalence and patterns of MDR-TB as well as the characterization of isolated NTM species. Methodology: All samples (1069) were subjected to smear microscopy, culture on Lowenstein-Jensen (LJ) media, and phenotypic drug susceptibility testing (DST) of MTB to isoniazid (INH), rifampin (RF), streptomycin (S), and ethambutol (E). GeneXpert was used for direct detection of MTB and RF resistance. Matrix-assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry (MS) was utilized for characterizing isolated NTM species. Results: M.tuberculosis (MTB) was isolated at a rate of 95.3% (1019/1069). MDR-TB was detected at rate of 7.16% with significant patterns for INH + RF + S + E (46.5%) and INR + RF (24.6%) (P-value <0.001). RF resistance was detected at a rate of 27.2% by GeneXpert. Seven NTM species (0.6%) were isolated in culture of which M.porcinum and M.fortuitum had confident identification by MALDI-TOF (score ≥1.8). Conclusion: MDR-TB rate was found to be 7.16% with significant dominance for INH + RF + S + E and INR + RF resistance patterns, while NTM rate was 0.6%.

Main Subjects

Files

Share

How to cite

Statistics