MOLECULAR EPIDEMIOLOGY OF AMPICILLIN-RESISTANT NON-BETA-LACTAMASE-PRODUCING HAEMOPHILUS-INFLUENZAE

Resistance to ampicillin without beta-lactamase production is not a fr equent occurrence among Haemophilus influenzae strains, This kind of r esistance is encountered in unencapsulated strains isolated from bronc hial secretions and ear, nose, and throat specimens and is exceptional in H. influenzae type b. We studied 29 of these strains from various areas in France and 2 reference strains. Strains were compared by usin g ribotyping, arbitarily primed PCR with two primers, and pulsed-field gel electrophoresis, Each technique enabled the identification of 20 to 23 different patterns among the 31 strains, The combination of the different patterns for the strains obtained by the different technique s provided 27 distinct profiles, According to these results, it seems that the clonal propagation of these resistant strains does not occur.