In Vitro Activity and MIC of Sitafloxacin against Multidrug-Resistant and Extensively Drug-Resistant Mycobacterium tuberculosis Isolated in Thailand
Author(s) -
Manoon Leechawengwongs,
Therdsak Prammananan,
Sarinya Jaitrong,
Pamaree Billamas,
Nampueng Makhao,
gnard Thamgdee,
Arirat Thanormchat,
Arisa Phurattanakornkul,
Somcharn Rattanarangsee,
Chate Ratanajaraya,
Areeya Disratthakit,
Angkana Chaiprasert
Publication year - 2017
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.00825-17
Subject(s) - ofloxacin , mycobacterium tuberculosis , microbiology and biotechnology , tuberculosis , drug resistance , quinolone , multiple drug resistance , biology , virology , antibiotics , ciprofloxacin , medicine , pathology
New fluoroquinolones (FQs) have been shown to be more active against drug-resistantMycobacterium tuberculosis strains than early FQs, such as ofloxacin. Sitafloxacin (STFX) is a new fluoroquinolone within vitro activity against a broad range of bacteria, includingM. tuberculosis . This study aimed to determine thein vitro activity of STFX against all groups of drug-resistant strains, including multidrug-resistantM. tuberculosis (MDRM. tuberculosis ), MDRM. tuberculosis with quinolone resistance (pre-XDR), and extensively drug-resistant (XDR) strains. A total of 374 drug-resistantM. tuberculosis strains were tested for drug susceptibility by the conventional proportion method, and 95 strains were randomly submitted for MIC determination using the microplate alamarBlue assay (MABA). The results revealed that all the drug-resistant strains were susceptible to STFX at a critical concentration of 2 μg/ml. Determination of the MIC90 s of the strains showed different MIC levels; MDRM. tuberculosis strains had a MIC90 of 0.0625 μg/ml, whereas pre-XDR and XDRM. tuberculosis strains had identical MIC90 s of 0.5 μg/ml. Common mutations within the quinolone resistance-determining region (QRDR) ofgyrA and/orgyrB did not confer resistance to STFX, except that double mutations of GyrA at Ala90Val and Asp94Ala were found in strains with a MIC of 1.0 μg/ml. The results indicated that STFX had potentin vitro activity against all the groups of drug-resistantM. tuberculosis strains and should be considered a new repurposed drug for treatment of multidrug-resistant and extensively drug-resistant TB.
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