In vitro bactericidal activity of antibiotic combinations against clinical isolates of Mycobacterium chelonae.

Mycobacterium chelonae is one of the most antibiotic-resistant species of the pathogenic, rapidly-growing mycobacteria. The objective of this study was to evaluate the bactericidal activity of classical and new potential drugs, alone and in combinations, against clinical isolates of Mycobacterium chelonae. Clarithromycin was seen to be the most bactericidal drug. In drug combinations, this compound is most useful with gentamicin, fluoroquinolones, rifampicin, linezolid, other aminoglycosides, doxycyline and carbapenems. The combination of tobramycin with ciprofloxacin or moxifloxacin also exhibits similar activity. In conclusion, this study on bactericidal activity of drug combinations against Mycobacterium chelonae confirms the utility of clarithromycin associated with other drugs, and, of the new drugs, the value of moxifloxacin and linezolid.