[Prevalence of antibiotic resistance of Haemophilus influenzae isolated in France: a year of activities of the network of surveillance for H. influenzae infections]

Abstract

The prevalence of antimicrobial resistance among clinical isolates of Haemophilus influenzae was assessed in France. A total of 705 isolates, obtained from CSF (98 strains), blood (76), ears (118), eyes (164), lower respiratory tract specimens (144), genital specimens (28), and various other specimens (71) were examined. These isolates were obtained from microbiological laboratories distributed throughout France and were sent to the Center for the study of H. influenzae during one year. Biotype of isolates was determined by use of API 10 E system and serotype was determined by slide agglutination procedure. All isolates were examined for beta-lactamase production with a chromogenic test. Susceptibility to ampicillin, cefotaxime, gentamicin, kanamycin, chloramphenicol, tetracycline, minocycline, erythromycin and rifampicin was determined by disk diffusion test and MIC determination by agar dilution procedure. Drug resistance was observed for 92 strains (13%). The overall resistance was 11.2% to ampicillin (all but one strain were beta-lactamase producers), 9% to tetracycline (Tc), 3.4 to chloramphenicol (Cm) and 6.8% to kanamycin (Km). Eleven phenotypes of resistance were observed: the most frequently observed were Ap-Km-Tc, Ap, Ap-Km-Cm-Tc, Ap-Tc, Ap-Km, Tc. Antimicrobial resistance rates varied by specimens: resistance to ampicillin concerned 12.2% of the strains from CSF, 10.5% from blood, 12.5% from sputum, 16.1% from ears, 6.7% from eyes; tetracycline resistance concerned 14.2%, 10.5%, 10.4%, 7.6% and 4.8% of the same strains respectively; resistance to chloramphenicol concerned 4%, 5.2%, 1.3%, 3.3% and 2.4% of the strains respectively.(ABSTRACT TRUNCATED AT 250 WORDS)