[Occurrence of Moraxella catarrhalis in patients with respiratory tract infections].

The study was undertaken to evaluate the incidence of Moraxella catarrhalis in patients with respiratory tract infections. Overall 514 specimens including 370 throat swabs and 114 sputum specimens were examined. The 78 strains isolated basing on morphological and biochemical characteristics were classified as Moraxella catarrhalis. The sensitivity of the strains to antibiotics was also estimated. The frequency of M. catarrhalis isolation from the throat swabs (15.9%) was higher than from the sputum (13.2%). Selected 25 specimens of sputum were tested simultaneously by quantitative and qualitative methods. Quantitative method was more sensitive (84% positive findings) than qualitative method (60% positive findings). Resistance to ampicillin was found in 52 (66.7%) strains of M. catarrhalis determined mainly by beta-lactamase production (over 70% strains were producers of beta-lactamase). All strains were sensitive to ofloxacin and amoxycillin/clavulanic acid combination. The frequency of M. catarrhalis isolation was higher in autumn-winter period than in summer (May-September). We conclude that M. catarrhalis, beside Streptococcus pyogenes (20.2%) and Streptococcus pneumoniae (17.1%), are the most frequently isolated bacteria in patients with respiratory tract infections.