Susceptibility to beta-lactams of Haemophilus influenzae, Streptococcus pneumoniae and Branhamella catarrhalis in a district general hospital during broncho-pulmonary infections

Most cases of chronic bronchitis infections are due to Haemophilus influenzae, Streptococcus pneumoniae and/or Branhamella catarrhalis. The aim of our study was to assess the bacteriological value of amoxicillin + clavulanic acid which is presumptively administered in such clinical conditions in the chest medicine department of our hospital. We have retrospectively analysed over a four-year period the susceptibility to beta-lactams of 405 strains isolated from 374 patients. The frequency of decreased susceptibility to beta-lactams was 17,5 % (28/160) in S. pneumoniae with 29 % (8/28) highly resistant strains. The frequencies of penicillinase secretion in H. influenzae and B. catarrhalis were 22 % (43/192) and 79 % (42/53) respectively. These figures, which are slightly lower than other French figures, justify our presumptive antibiotic therapy (amoxicillin only may be given as a relay in many cases). This study enables us to rationalize the antibiotic therapy and will probably induce decreased costs of the antibiotic therapy in the chest medicine department.