[Detection of beta-lactamase in samples obtained after tonsillectomy in children].

Production of beta-lactamase was detected using a microbiological assay (Guts test) in samples of tonsils, and by in Haemophilus growing from the same samples of both tonsils obtained from 30 children aged 2 to 13 years (18 aged < 6 years and 12 aged > or = 6 years). Two pieces from each tonsil, core and superficial, were studied. The procedure included direct microscopic examination of smears, and culture to identify Haemophilus, beta-haemolytic streptococci and Streptococcus pneumoniae. Guts test was positive in tonsillar tissue obtained from 26 children (14 aged < 6 years and 2 aged > or = 6 years) (p < 0.01). In 10 of them (9 aged < 6 years and 1 aged > or = 6 years) (p < 0.05) grew beta-lactamase producer Haemophilus influenzae. One to three varieties of Haemophilus could be found in 28 children (11 with H. influenzae = 5 beta-lactamase +, 8 with Haemophilus parainfluenzae = 3 beta-lactamase +); Group A, C, or G streptococci in 5 children, but no strain of Streptococcus pneumoniae. No difference could be demonstrated between core and superficial samples: beta-lactamase activity was positive in superficial samples from 26 children and core samples from 24. Almost all bacteria described grew from superficial as well as (slightly but no significantly less) from core samples.