OBJECTIVE To investigate the clinical characteristics of Haemophilus influenzae strains isolated from respiratory trace specimens of the hospitalized adult patients with pneumonia and analyze the change of drug resist-ance from 2022 to 2024.METHODS The clinical data and drug susceptibility testing data for the H.influenzae strains isolated from respiratory tract specimens were collected from the 1 462 adult patients with pneumonia who were hospitalized in Foshan Sanshui District People's Hospital from Jan.2022 to Dec.2024.The clinical character-istics of the patients with H.influenzae infection and the change of drug resistance were retrospectively analyzed with the use of SPSS 22.0 and WHONET 5.6 software.RESULTS Totally 223 of 1462 hospitalized patients were diagnosed with H.influenzae infection,the detection rate of H.influenzae was 16.38％among the male pa-tients,higher than 12.00％among the female patients,and there was significant difference(P＜0.05);the de-tection rate was higher in summer and autumn(P＜0.05).The patients with chronic obstructive pulmonary dis-ease accounted for 34.08％.The result of drug susceptibility testing for the 223 strains of H.influenzae showed that the positive rate of β-lactamase was 63.23％,and the isolation rate of β-lactamase-negative ampicillin-resistant strains was 9.86％.There was significant difference in the drug resistance rate to azithromycin among the H.in-fluenzae strains isolated from 2022 to 2024(x2=6.715,P=0.035),and the drug resistance rate of the H.in-fluenzae strains to azithromycin was higher in 2024(40.77％).CONCLUSIONS The male patients and the patients with COPD are dominant among the hospitalized adult pneumonia patients with H.influenzae infection,which is prevalent in spring and winter.The drug resistance analysis shows that the positive rate of β-lactamase and the drug resistance rate to ampicillin are high,and it should be aware of the empirical use of penicillin.The drug re-sistance rate to azithromycin is increased year by year;the multidrug-resistance in the H.influenzae strains may pose new challenge to the clinical diagnosis and treatment.

OBJECTIVE To investigate the clinical characteristics of Haemophilus influenzae strains isolated from respiratory trace specimens of the hospitalized adult patients with pneumonia and analyze the change of drug resist-ance from 2022 to 2024.METHODS The clinical data and drug susceptibility testing data for the H.influenzae strains isolated from respiratory tract specimens were collected from the 1 462 adult patients with pneumonia who were hospitalized in Foshan Sanshui District People's Hospital from Jan.2022 to Dec.2024.The clinical character-istics of the patients with H.influenzae infection and the change of drug resistance were retrospectively analyzed with the use of SPSS 22.0 and WHONET 5.6 software.RESULTS Totally 223 of 1462 hospitalized patients were diagnosed with H.influenzae infection,the detection rate of H.influenzae was 16.38％among the male pa-tients,higher than 12.00％among the female patients,and there was significant difference(P＜0.05);the de-tection rate was higher in summer and autumn(P＜0.05).The patients with chronic obstructive pulmonary dis-ease accounted for 34.08％.The result of drug susceptibility testing for the 223 strains of H.influenzae showed that the positive rate of β-lactamase was 63.23％,and the isolation rate of β-lactamase-negative ampicillin-resistant strains was 9.86％.There was significant difference in the drug resistance rate to azithromycin among the H.in-fluenzae strains isolated from 2022 to 2024(x2=6.715,P=0.035),and the drug resistance rate of the H.in-fluenzae strains to azithromycin was higher in 2024(40.77％).CONCLUSIONS The male patients and the patients with COPD are dominant among the hospitalized adult pneumonia patients with H.influenzae infection,which is prevalent in spring and winter.The drug resistance analysis shows that the positive rate of β-lactamase and the drug resistance rate to ampicillin are high,and it should be aware of the empirical use of penicillin.The drug re-sistance rate to azithromycin is increased year by year;the multidrug-resistance in the H.influenzae strains may pose new challenge to the clinical diagnosis and treatment.