Related Experiment Video
Updated: May 24, 2025

Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray
Published on: April 25, 2014
The implications of mutations in multiple genes associated with ethambutol resistance among multidrug-resistant
Ma-Chao Li1, Wei Wang1, Tong-Yang Xiao2
1National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China.
Objectives:
To assess the mutation effects of ethambutol (EMB) resistance-associated genes, including embCAB operon, ubiA, embR, and aftA, on the EMB resistance levels among multidrug-resistant tuberculosis (MDR-TB) isolates from China.
Methods:
A total of 159 MDR-TB from China had their EMB MICs quantified, and the sequences of the four ethambutol resistance-associated regions were analyzed. A multivariate regression model was established to evaluate the effects of mutations on EMB resistance.
Results:
Our results showed that overall 95.6% (109/114 isolates) of EMB-resistant isolates harbored at least one mutation within the regions associated with EMB resistance. Most mutations were in embB, particularly in the embB300-500, and the embC-embA intergenic regions. Mutations in other genes were seldom seen and mainly occurred along with mutations in the embB or the embC-embA among the EMB-resistant isolates. DNA sequencing of the embB300-500 and the embC-embA was the most effective approach for detecting EMB resistance, with an accuracy of 91.2%. Nevertheless, some EMB-susceptible isolates still had a single mutation in the gene related to EMB resistance. Moreover, there was a significant correlation between EMB high-level resistance and multiple mutations.
Conclusion:
Distinct individual mutations, as well as multiple concurrent mutations, within EMB resistance-associated genes, contributed to variable levels of EMB resistance. These results have broadened our understanding of the molecular characteristics of EMB resistance in China.
Related Concept Videos
Pulmonary Tuberculosis V
Latent tuberculosis infection occurs when TB bacteria are present in a person's body, but are not causing illness or symptoms. It is not contagious, and preventive treatment is crucial to avoid the...
Pulmonary Tuberculosis I
Causative Organism
The primary infectious agent causing tuberculosis is Mycobacterium tuberculosis, a slow-growing, acid-fast, aerobic rod that exhibits sensitivity to heat and ultraviolet light. Instances of Mycobacterium bovis and Mycobacterium avium contributing to the development of TB infection are rare.
Mode of...
Mismatch Repair
Pulmonary Tuberculosis IV
Several diagnostic approaches are used to detect TB. The conventional method is the Tuberculin Skin Test (TST), also known as the Mantoux test. However, this method has...
Pulmonary Tuberculosis III
The first classification is based on the development of the disease, and it includes the following categories:
Combined Effects of Drugs: Synergism
Such synergistic combinations...

