[Laboratory and clinical investigation on lower respiratory tract infection by Haemophilus influenzae].
To improve the positive rate of Hi isolation and to study the epidemiology, antibiotic sensitivity and clinical characteristics of the lower respiratory tract infection by Hi. Modified Columbia chocolate agar(ICCA) was compared with blood agar staphy stick (BASS) for the primary isolation of Hi from sputa. The sensitivities of 20 antibiotics to Hi were determined in vitro by KB method and MICs of 12 antibiotics were determined by broth microdilution method. The clinical characteristics of 92 cases with lower respiratory tract infection by Hi were analyzed. The isolation rate of Hi by ICCA was 20%, which was higher than 13% of BASS(P < 0.01). The third generation cephalosporins and the quinolones were most active against Hi. The resistant rate against Hi of ampicillin was 21%, however, that of the third generation cephalosporins was 45%-49%. 67(73%) of 92 cases were bronchopneumonia. The isolation rate of Hi could be improved by ICCA. The clinical characteristic of lower respiratory tract infection by Hi was not specific. There has been a steady increase of antibiotic resistance during these years.