An Analysis On Infection Status And Drug Resistance Of Haemophilus Influenza Among Preschool Children In A City

[Objective] To explore the infection status, main strains of Haemophilus influenza among pre-school children in certain city, as well as theirs drug-resistance to commonly used antibiotics, and provide scientific evidence of constituting preventive polices and measures for relative departments[Methods] Three day-care nurseries were chosen according to the method of cluster sampling, in which 360 children were inquired the history of Hib combined vaccination and specimens were taken. The isolation and identified of Hi was tested, as well as biological, serological and molecular typing (we used PFGE to molecular type).Drug sensitivity test was followed the disc diffusion method recommended by NCCLS in 2006. SPSS13.0 Excel2003 and Bionumerics was for data input and analysis, calculating the population ratio, Hi positive rate and the relevant parameters . Statistical analysis was performed with Chi Square Test. P<0.05 was considered significant.[Results] 90 Hi strains were isolated from 360 samples (positive rate was 25.0%).There were significant differences between positive rates of winter and summer which were 32.2% and 17.7% respectively (x~2=10.015, P=0. 002). According to biological typing, Hi type II and type III were the most common strains, accounting of 28.9% and 40.0% respectively. The serological typing of Hi include a (1 cases, 1.1%), b (8 cases, 8.9%), d (3 cases, 3.3%) and NTHi (78 cases, 86.7%). There were 38 types by PFGE showing genetic polymorphism distribution. All of 90 Hi strains were sensitive to cefotaxime, cefixime, rifampin, azithromycin and ofloxacin, but some of them had drug resistance to cotrimoxazole(32 cases, 35.5%),ampicillin (18 cases,20.0% ), chloromycetin(16 cases, 18.8 %) and tetracycline(14 cases,15.5%).The differences of Hib vaccine inoculation between winter and summer was significant (x~2=0.550, P=0.760) .The vaccination rates were 37% in winter and 41% in summer and unvaccinated children were 52% (93 cases) and 50% (90 cases) respectively.[Conclusions] Vaccination rates of preschool children was in the low level but Hi nasopharynx infection rate was in the high level in Shenzhen. The Hi positive rate was higher in winter than in summer. According to biological typing, there were type II and III chiefly. Serotyping mainly constituted to NTHi. Molecular typing showed no dominant strain but genetic polymorphism distribution.Hi were sensitive to cefotaxime, cefixime, rifampin, azithromycin and ofloxacin relatively, which indicates cephalosporins, macrolides, quinolones can be used to cure Hi infection efficiently. However, cotrimoxazole, ampicillin, tetracycline, chloramphenicol were resistant by Hi in various degree. So antibiotics like cephalosporins and macrolides might be recommended as the first line therapy for Hi infection.