In vitro activity of moxifloxacin and linezolid against mycobacteria

BELÉN IMPERIALE; BEATRÍZ DI GIULIO; NORA MORCILLO

Berlin

Congreso; 18 Congreso Anual de la Sociedad Europea de Medicina Respiratoria (ERS); 2008

Sociedad Europea de Medicina Respiratoria (ERS)

The advent of the extensively drug-resistant Mycobacterium tuberculosis (MTB) strains (XDR-TB), the increase of multidrug-resistant tuberculosis (MDR-TB) and the appearance as etiological agents of the intrinsically drug-resistant non-tuberculous mycobacteria (NTM) frequently associated to HIV condition, are worsening the chemotherapeutic panorama of the diseases caused by mycobacteria. Minimal inhibitory concentration (MIC) of moxifloxacin (MOX) and linezolid (LZ) were determined by the colorimetric microplate-based method using 3-(4,4-dimethylthiazollyl-2)-2,5 diphenyl tetrazolium bromide (M-MTT). The assay was carried out on 42 MDR-TB and 34 NTM isolated in Argentina during 2005-2007. MIC50 and MIC90 for MTB and MOX were (mg/L) 8.00 respectively. Results of MICs by M-MTT were obtained in an average of 8 days and they were compared to those obtained by the agar proportion method. Full agreement between sensitivity results obtained by both methods was observed. The microplate system could be used as a simple, rapid and low cost technology to explore susceptibility of mycobacteria resistant to anti-TB agents to several drugs like MOX and LZ, which could potentially be included in therapeutic schemes.