Correlating Minimum Inhibitory Concentrations of ofloxacin and moxifloxacin with gyrA mutations using the genotype MTBDRsl assay. Issue 2 (March 2015)

• Record Type: Journal Article
• Authors: Kambli, Priti; Ajbani, Kanchan; Sadani, Meeta; Nikam, Chaitali; Shetty, Anjali; Udwadia, Zarir; Rodwell, Timothy C.; Catanzaro, Antonino; Rodrigues, Camilla
• Is Part Of: Tuberculosis. Volume 95:Issue 2(2015)
• Page Start: 137
• Page End: 141
• Publication Date: 2015-03
• Subjects: 616.995
• DOI: 10.1016/j.tube.2014.11.003
• Languages: English
• ISSNs: 1472-9792

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Summary</title> <sec> <title id="sectitle0015">Objective</title> <p id="abspara0010">To correlate <italic>gyrA</italic> mutations found on the Genotype MTBDR<italic>sl</italic> assay in <italic>Mycobacterium tuberculosis</italic> (<italic>MTB</italic>) isolates with Minimum Inhibitory Concentrations (MICs) to the fluoroquinolones compounds ofloxacin (OFX) and moxifloxacin (MXF).</p> </sec> <sec> <title id="sectitle0020">Methods</title> <p id="abspara0015">MICs for OFX and MXF were ascertained for 93 archived clinical <italic>MTB</italic> isolates that showed <italic>gyrA</italic> mutations at Ala90Val, Ser91Pro, Asp94Ala, Asn/Tyr, Gly and His. Thirty fluoroquinolones susceptible isolates as determined by presence of all wild-type <italic>gyrA</italic> bands on the Genotype MTBDR<italic>sl</italic> assay were also included.</p> </sec> <sec> <title id="sectitle0025">Results</title> <p id="abspara0020"> <italic>gyrA</italic> mutations at Ala90Val (<italic>n</italic> = 25), Ser91Pro (<italic>n</italic> = 6), Asp94Ala (<italic>n</italic> = 4), Asp94Asn/Tyr (<italic>n</italic> = 13), Asp94Gly (<italic>n</italic> = 42) and Asp94His (<italic>n</italic> = 3) were observed. Isolates with mutations at Ala90Val or Ser91Pro had MIC<sub>90</sub> of 4.0 μg/ml and 1.0 μg/ml for OFX and MXF, respectively, and isolates with mutations at Asp 94Ala, Asn/Tyr, Gly and His had MIC<sub>90</sub> of 8.0 μg/ml, and 2.5 μg/ml for OFX and MXF, respectively.</p> </sec> <sec> <title id="sectitle0030">Conclusions</title> <p id="abspara0025"> <italic>MTB</italic> MICs were found to be consistently lower for MXF than for OFX among isolates with the same <italic>gyrA</italic> mutation (e.g. Ala90Val). The majority of <italic>MTB</italic> isolates containing mutations at Asp94Ala, Asn/Tyr, Gly and His in <italic>gyrA</italic> were associated with a moderate level of resistance to MXF (MIC = 2.5 μg/ml), although 3 isolates with the mutations Asp94Asn/Tyr/Gly were associated with a high level of resistance to both fluoroquinolones (MXF MICs = 5.0–8.0 μg/ml, OFX MICs = ≥10.0 μg/ml).</p> </sec> </abstract>