ABSTRACT
Objective To investigate the epidemic strains of biological type, drug resistance, and the basic clinical characteristics of haemophilus influenzae(Hi)isolated from hospitalized adults with lower respiratory tract infection in Chengdu area.Methods A prospective cross-sectional study was conducted to analyze the biological typing,capsular genes detected by PCR technique,and drug resistance tested by drug sensitive test of Hi epidemic strains isolated from the sputum of adults aged above 18 years who were hospitalized in two tertiary hospitals of west Sichuan in China.Results The positive rate of pathogenic bacteria in adults aged above 18 years who were hospitalized in the two hospitals was 46.71%(15 447/33 069)between November 2013 and October 2014.The positive rate of Hi isolated from the sputum of 100 adults with lower respiratory tract infection was 0.31%(101/33 069).The constituent ratio of Hi in lower respiratory tract infection pathogens was 0.65%(101/15 447).The Hi were all undifferentiated type detected by PCR,and the biological typing of Hi were typeⅠ(42.57%),Ⅳ(29.7%),Ⅱ(15.84%),Ⅲ(9.9%),Ⅶ(1.98%), and Ⅵ(0.9%).The diseases of Hi positive were acute phase of chronic obstructive pulmonary disease(59%), pneumonia(35%), and bronchitis(6%), in which community acquired infection was 55%.The rate of β-lactamase enzyme production was 38.61%.The frequencice of β-lactamase -nonproducing-ampicillin-resistant(BLNAR)strains was 2.97%,and of intermediary strains was 4.95%(5/101).The drug resistance rate of amoxicillin and clavulafiate was 2.97%.The drug resistance rate of cefuroxime was 12.87%, and intermediary rate was 12.87%.The drug resistance rate of cefaclor was 29.7%,and intermediary rate was 8.91%.The drug resistance rate of cefotaxime and ofloxacin was 6.93%and 1.99%.There were no obvious statistical differences between the drug resistance rates of the two hospitals.Conclusions The Hi epidemic strains isolated from the sputum of adults with lower respiratory tract infection were all undifferentiated type,and the common biological types were Ⅰ,Ⅳ,Ⅱ, andⅢ in west Sichuan in China.It should pay attention to the BLNAR strains and ofloxacin-resistant strains.