Antimicrobial Resistance in Haemophilus influenzae Isolated from Blood, Cerebrospinal Fluid, Middle Ear Fluid and Throat Samples of Children. A nationwide study in Finland in 1988-1990

A nation-wide survey of the prevalence of antimicrobial resistance in Haemophilus influenzae was conducted on isolates collected in 1988–90 from middle ear fluid (MEF), blood, or cerebrospinal fluid (CSF) in infected children or throat samples of healthy children. Altogether 885 strains were examined regarding capsular type b, β-lactamase production and the minimal inhibitory concentration (MIC) of ampicillin, cefaclor, erythromycin, tetracycline, chloramphenicol, trimethoprim and trimethoprim-sulfamethoxazole for these strains was determined by the agar dilvtion method. 99% (578/585) of MEF isolates 93% (112/121) of throat isolates, but only 6% (10/179) of blood/CSF isolates were not of type b (Hib). The rate of β-lactamase production was 11.4% among Hib strains, 8.0% among non-type b MEF isolates, and 4.5% among non-type b throat isolates. No increase in the prevalence of β-lactamase production in H. influenzae has taken place in Finland since the early 1980s. Resistance to ampicillin among strains that...