DISTRIBUTION AND ANTIBIOTIC RESISTANCE OF HAEMOPHILUS ISOLATED FROM RESPIRATORY TRACT

Objective To investigate the distribution and antibiotic resistance of Haemophilus so as to provide the basis for diagnosis and therapy for respiratory tract infection.Methods A total of 271 Haemophilus strains were identified by hand and VITEK instrument.Then,β-lactamase was measured by nitrocefin paper method while the resistance of 8 antibiotics to Haemophilus were tested by KB method.Results Among 271 Haemophilus strains,Hoemophilus influenzae(HIN) accounted for 21.0%(57/271),in which β-lactamasepositive HIN accounted for 15.8%,and β-lactamase-negative ampicillin-resistant(BLNAR) Haemophilus influenzae 10.5%.Haemophilus parainfluenzae(HPI) accounted for 79.0%(214/271),in which β-lactamase-positive HPI accounted for 18.2%,and BLNAR HPI 14.5%.The incidence of HPI infection was significantly higher than that of HIN,but it was not related with age or sex.The rate of β-lactamase production in children(31.3%) was higher than that in adults(8.2%,P0.05).Antibiotic resistance rate to azithromycin was 3.3%,while to Trimethoprim/Sulfam 74.2%.All of the β-lactamase-positive strains were resistant to ampicillin.BLNAR Haemophilus strains were more resistant to cephems,ampicillin/sulbactam,ciprofloxacin,or chloramphenicol than β-lactamase-positive Haemophilus.Conclusion The incidence of β-lactamase production is increasing in children.The problem of antibiotic resistance of β-lactamase-negative ampicillin-resistant Haemophilus must be noticed.Azithromycin may be the first selection for clinical therapy.