Bacteriological aspects of infections of the upper respiratory tract.

In this introductory presentation, the bacteriology of acute otitis media, sinusitis and orofacial infections is surveyed, and recent data on antibiotic resistance of the most common pathogenic bacteria are reported. In addition, the difference in the immunogenic effect of capsular polysaccharides from pneumococci and Haemophilus influenzae in children of different ages is mentioned. In acute otitis media and sinusitis, pneumococci and H. influenzae are the most common isolates followed in frequency by Branhamella catarrhalis and streptococci group A. It should be emphasized that the average relative risk of otitis media with effusion is much higher in children with viral respiratory infections than in children with nasopharyngeal colonization with pneumococci or H. influenzae. Anaerobic bacteria are the most common causes of odontogenic infections. Penicillin remains the most active of the currently available antibiotics against streptococci group A. Resistance to penicillin of clinical isolates has still not been documented, although resistance may occur to erythromycin and tetracycline. In pneumococci isolates obtained in Sweden, a relative resistance to penicillin occurs in a low percentage. They may also be resistant to erythromycin and tetracycline. The frequency of beta-lactamase producing H. influenzae has been followed nation-wide in Sweden during recent years. The mean frequency varies around 3-4% with local and seasonal peaks up to 12%. The majority of the H. influenzae isolates in Sweden are not fully sensitive to erythromycin, but resistance to chloramphenicol occurs. Most strains (including beta-lactamase producing) are sensitive to co-trimoxazole, cefuroxime, cefotaxime, cefotriaxone and cefaclor. Over 40% of clinical isolates of B. catarrhalis in Sweden produce beta-lactamase.(ABSTRACT TRUNCATED AT 250 WORDS)