Antibiotic resistance of bacteria responsible of acute respiratory tract infections in children

Background and aims. Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are the most common causative agents of acute respiratory tract infections (RTIs). The objective of this study was to assess their susceptibility to several antibiotics.
Materials and methods. A total of 58 strains (16 S. pneumoniae, 19 H. influenzae and 23 M. catarrhalis) were isolated from samples collected in two paediatric centres, and their susceptibility to commonly used antibiotics tested by E-test.
Results. Among H. influenzae isolates, 10.5% were resistant to ampicillin (all β-lactamase-positive), and 88.9% were susceptible to cefaclor. High β-lactam resistance rates (penicillin: 31.3% and cephalosporins: 18.7 to 31.3%) had been observed among S. pneumonia strains. Only 50% of isolates were susceptible to azithromycine. 91.3% of M. catarrhalis isolates β-lactamases producers were resistant to ampicillin while susceptible to the most tested antibiotics.
Conclusions. Except M. catarrhalis β-lactamases producing strains, frequency of antibiotic resistance was mainly observed among S. pneumoniae, and to a lesser extent among H. influenzae clinical isolates, suggesting the need for continuous surveillance of antimicrobial resistance patterns in the management of RTIs.