Rapid detection of ofloxacin resistance in Mycobacterium tuberculosis by two low-cost colorimetric methods: resazurin and nitrate reductase assays.
We have evaluated the performance of two rapid, low-cost methods for the detection of ofloxacin (OFX) resistance with 95 Mycobacterium tuberculosis isolates from countries with high multidrug-resistant tuberculosis endemicity. Results obtained by nitrate reductase and resazurin assays showed 100% agreement with those of the proportion method on 7H11 agar using 2 mug of OFX/ml. We confirmed the resistance of all isolates found to be resistant to OFX by the Mycobacterium Growth Indicator Tube system, and complete agreement among all methods was observed. Nitrate reductase and resazurin assays are rapid, simple, low-cost methods and might become inexpensive alternative procedures for rapid detection of OFX resistance in low-resource countries.
Martin
Anandi
A
Mycobacteriology Unit, Institute of Tropical Medicine, Nationalestraat, 155, Antwerp B-2000, Belgium. amartin@itg.be
Palomino
Juan Carlos
JC
Portaels
Françoise
F
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003124:Colorimetry / Q000191:economics / Q000379:methods; D024881:Drug Resistance, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000191:economics / Q000379:methods; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000378:metabolism*; D015242:Ofloxacin / Q000494:pharmacology*; D010078:Oxazines / Q000378:metabolism*; D011933:Reagent Kits, Diagnostic; D013997:Time Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000382:microbiology; D014966:Xanthenes / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D010078:Oxazines; D011933:Reagent Kits, Diagnostic; D014966:Xanthenes; C005843:resazurin; D015242:Ofloxacin; D009565:Nitrate Reductases; D050901:Nitrate Reductase