[Extracellular and intracellular activity of sparfloxacin against Mycobacterium avium complex and Mycobacterium xenopi].

Activity of the new fluoroquinolone sparfloxacin against 30 strains of M. avium complex and 25 strains of M. xenopi was tested in vitro. Sparfloxacin was used alone (determination of MICs and MBCs) and in combination with ethambutol and rifabutin. Synergy studies with determination of the FIC and FBC indices showed that the sparfloxacin-ethambutol combination was synergistic against 10 M. avium complex strains and 12 M. xenopi strains. With the three-drug combination (sparfloxacin-ethambutol-rifabutin), synergy was found against 12 M. avium and 14 M. xenopi strains. Studies of intracellular bacteria showed that the decrease in viable bacteria with the three-drug combination was 1 log for M. avium and 2 log for M. xenopi.