[The penicillin susceptibility of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus in persons suffering from upper respiratory tract infections].

The susceptibility to penicillin was tested in 293 strains of S. aureus, 162 strains of H. influenzae, 60 strains of M. catarrhalis and 77 strains of S. pneumoniae, isolated from persons suffering from upper respiratory tract infections. Penicillin susceptibility testing has been performed by the disc diffusion technique. Beta-lactamase production in the penicillin-resistant strains of H. influenzae, M. catarrhalis and S. aureus was detected with nitrocefin impregnated disc. In beta-lactamase positive strains, the susceptibility to amoxacillin/clavulanic acid (AMC) was determined. Nearly half (46.3%) of H. influenzae strains was resistan to ampicillin. In the remaining bacteria, the percentage of resistance was 2.6% for S. pneumoniae, 82.4% for M. catarrhalis and 88.1% for S. aureus strains. All strains resistant to penicillin (ampicillin) produced beta-lactamase and were AMC sensitive.