In vitro activity of levofloxacin against streptococcus pneumoniae and streptococci strains isolated in france during 1999-2000

Objective: To assess the activity of levofloxacin against pneumococci and streptococci. Method. One thousand two hundred and fifty five strains of pneumococci (1015) and streptococci (240) was obtained from October 1999 to March 2000 in 46 participant centers: 35 hospital laboratories and 11 community laboratories. Susceptibilities were determined by the standard disc-diffusion test and MICs of beta-lactams (penicillin, amoxicillin, cefotaxime, cefpirome, cefpodoxime and cefuroxime) by Etest. MICs of levofloxacin were measured, for a sample of susceptible strains and for all strains that were resistant by disc-diffusion. Results: 41.3% and 31.1% of S. pneumoniae strains were susceptible, 34% and 57.4% intermediates, 24.7% and 11.5% were resistant to penicillin by Etest in hospital and in community laboratories, respectively. Percentages of susceptibilities to levofloxacin were of 98.2% (hospitals) and 100% (community), and of 41.2% (hospital) and 21.6% (community) to erythromycin. The highest, percentage of non susceptible strains observed in the community was probably related to the fact that strains isolated in community mostly originated from children: 64.2% versus 26.5%. Susceptibility of Streptococcus pyogenes to penicillin remains constant, 100% of strains being susceptible. Macrolides still exhibit good activity against this species with 93.3% of susceptible strains to erythromycin. Percentage of susceptible strains of S. pyogenes was 97.8. Viridans group streptococci are less susceptible to antibiotics with 73.5% and 47% of strains being susceptible to penicillin and macrolides, respectively. 95.4% of strains were susceptible to levofloxacin. Conclusion: The results of this study show the good in vitro activity of levofloxacin against S. pneumoniae in hospital and in community. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.