Abstract
The chronological variations of isolates from otorrhea referred to our laboratory during the last 8 years were studied. Of 149 strains isolated from 105 patients with acute otitis media, 34 (22.8%) were Staphylococcus aureus, 25 (16.8%) H. influenzae, 19 (12.8%) Streptococcus pneumoniae and 18 (12.1%) A-β-streptococcus. There were 32:patients with acute and chronic otitis media caused by H. influenzae, of whom 90.6% were the children of age below 4 years. Three of 8 strains of H. influenzae isollated from otorrhea during the recent 2 years produced β-lactamase, and two of these 3 strains were isolated from patients undergoing antibiotic therapy such as ampicillin and cephalexin. Susceptibility of 53 isolates of H. influenzae including 9 β-lactamase-positive strains, was tested by an agar diffusion method using 106 CFU/ml as an inoculum. All the strains of β-lactamase-positive H. influenzae were inhibited by 3.13μg/ml of cefaclor and 0.79μg/ml of chloramphenicol.
