In vitro activity of pristinamycine against Streptococcus pneumoniae.

The activity of the pristinamycin was investigated using disk diffusion aga r or ATB PNEUMO system and MIC determination using reference liquid medium method (NCCLS) on 749 S. pneumoniae strains isolated in Aquitaine in 1999. We have realized the killing curves against 10 isolates selected from eryth romycin-susceptible and resistant S. pneumoniae strains. All the strains te sted by ATB PNEUMO system were susceptible to pristinamycin, using disk dif fusion agar, 6.8% of strains were intermediate or resistant. However the MI C's of pristinamycin determined by liquid dilution method against these str ains were < 1 mg/L. These data suggest that the zone of inhibition around t he disk was not corralated with MIC for erythromycin pneumococci and MIC te sting must be performed. The results of killing curves showed a very good a nd rapid bactericidal activity of pristinamycin within two hours for concen tration equal to 4 x MIC and four hours for 2 x MIC. (C) 2001 Editions scie ntifiques et medicales Elsevier SAS.