These findings reveal the importance of iga gene variability and expression levels in the establishment of disease phenotype. They identify nontypeable H influenzae IgA1 protease as a virulence factor and as a potential target for the development of new strategies to fight these important pathogens.

SUMMARYAn investigation was undertaken to determine the isolation rate and antibiotic resistance ofHaemophilus influenzae from the nasopharynx of young children. The 996 subjects studied were up to 6 years of age. H. influenzae was isolated from 304 (30 5 %) and strains of capsular type b from 11 (1 1 %). Age, sibling status, season, respiratory infection and antibiotic therapy all influenced isolation rates. The overall prevalence of antibiotic resistance in the strains isolated was ampicillin 5-4% (all fl-lactamase producers), cefaclor 0-3 %, chloramphenicol 1-3%, erythromycin 38-2 %, tetracycline 1 3 %, trimethoprim 5-4 % and sulphamethoxazole 0%. Ampicillin resistance was more common in type b than non-capsulated strains.

Objective-To investigate the epidemiology of invasive disease due to Haemophilus influenzae type b, the clones responsible, and the antibiotic resistance of the isolates.

No abstract

The in-vitro activity of a new macrolide antibiotic CP-62,993 (Pfizer Ltd) was determined for 420 bacterial isolates, comprising 150 Haemophilus influenzae, 48 Branhamella catarrhalis, 50 Staphylococcus aureus, 50 coagulase negative staphylococci, 50 beta-haemolytic streptococci, 50 Streptococcus pneumoniae and 22 oral streptococci. CP-62,993 was compared with erythromycin and penicillin (ampicillin in the case of H. influenzae). The MICs of CP-62,993 were found to be lower than those of erythromycin for the two Gram-negative species tested: this was particularly marked in the case of H. influenzae where a ten-fold difference in the MIC50 was observed (CP-62,993, 0.25 mg/l, erythromycin 2 mg/l). In general MICs of CP-62,993 were two-fold higher than those of erythromycin for the Gram-positive species studied, with the exception of the oral streptococci which were equally susceptible (MIC50 0.03 mg/l) to both macrolides. Activity similar to that of erythromycin was observed against Str. pneumoniae (MIC values 0.015-0.12 mg/l), Staph. aureus (MIC 0.12-1 mg/l) and beta-haemolytic streptococci (MIC 0.06-4 mg/l). Incubation in a CO2 enriched atmosphere decreased activity of both erythromycin and CP-62,993. The effect was more marked for CP-62,993, the MIC50s of all groups of organisms being increased four-fold when they were incubated in the presence of 5 or 10% CO2.