This video demonstrates an assay to evaluate the efficacy of drugs against Mycobacterium tuberculosis (Mtb) infection. An in vitro infection model containing Mtb/macrophage aggregates is generated that mimics in vivo infection. Upon introducing suitable antibiotics, their efficacy is tested via resuzarin assay to monitor the survival of bacteria with increasing drug concentrations.
Protocol
1. Culture Conditions for Green Fluorescent Protein Expressing M. tuberculosis mc26206 (Mtb-GFP) NOTE: The M. tuberculosis H37Rv derived auxotroph strain mc26206 (ΔpanCD, ΔleuCD) transformed with the gfp (green fluorescent protein) expressing plasmid pMN437 is used throughout this protocol. It is possible to substitute the Mtb-GFP strain with non-gfp expressin…
Representative Results
Figure 1: Drug plate layout. (A) Example template of the drug challenge plate used in step 4. This allows for the parallel testing of two drugs in triplicate wells at 8 defined concentrations. As a representative experiment, we used rifampicin (RIF) and moxifloxacin (MOXI) starting at 2 µM and 2.5 µM, respectively. (B) An alternative template for throug…
Declarações
The authors have nothing to disclose.
Materials
7H9
BD Difco
271310
Follow manufacturer's recommendations
Middlebrook OADC
BD Biosciences
212351
Tyloxapol
Sigma
T8761
Prepare 20% stock solution in H2O; filter sterilize
D-Pantothenic acid hemicalcium salt
Sigma
P5710
Prepare 24 mg/ml stock solution in H2O; filter sterilize
L-leucine
MP Biomedicals
194694
Prepare 50 mg/ml stock solution in H2O; filter sterilize
Hygromycin B
EMD Millipore
400051
Prepare 200 mg/ml stock solution in H2O
Nalgene Square PETG media bottle
Thermo Fisher
2019-0030
RPMI 1640 media
Hyclone
SH30027.01
Fetal Bovine Serum
Atlanta Biologicals
S12450H
L-glutamine
Corning
MT25005CI
HEPES
Hyclone
SH30237.01
Cytation 3 plate reader
Biotek
Interchangable with any fluorescent plate reader and microscope
Gen5 Software
Biotek
Recording and analysis of rezasurin coversion
Rifampicin
Fisher Scientific
BP2679250
Prepare 10 mg/ml stock solution in H2O
Moxifloxacin Hydrochloride
Acros Organics
457960010
Prepare 10 mg/ml stock solution in H2O
Resazurin Sodium Salt
Sigma
R7017
Prepare 800 μg/mL stock solution in H2O; filter sterilize
Tween-80
Fisher Scientific
T164500
Prepare 20% stock solution in H2O; filter sterilize