Carrying rate and the epidemic characteristics of haemophilus influenzae isolated from healthy children in Zhangjiakou

OBJECTIVE To investigate the infection status, epidemic characteristics and resistance to common antibiotics of haemophilus influenzae (HI) among children subjected to respiratory tract infection of Zhangjiakou city. To provide scientific evidences for preventing, alleviating and controlling HI infection in this region. METHODS HI strains were isolated from throat swabs from healthy children. The antibiotics susceptibility was identified by K-B method, and β-lactamase was cefinase paper method; isolates were conducted on biological typing, random amplified polymorph DNA (RAPD) was used to identify the genotype and homology of these strains. RESULTS 31 HI strains were isolated from 100 samples of healthy children, positive rate was 31%. All of the 31 HI strains were sensitive to imipenem, chloromycetin, cefaclor, etc. The resistant rate to trimethoprim-sulfamethoxazol and ampicillin were 38.7% and 16.1%, 5 strains were β-lactamase positive, accounting for 16.1%. Biotypes Ⅵ and Ⅷ were the prevalent biotypes accounting for 32.4% and 22.6%, respectively.The cluster analysis using RAPD indicated that HI colonizing on healthy children in this city had few cross-infection and there was no obvious central distribution trend. CONCLUSION Compared with the results of ten years ago, it has changed in HI separation rate, biotype and antibiotics resistance. RAPD cluster analysis shows that HI colonizing on healthy children in this city has few cross-infection and there is no obvious central distribution trends.