STUDY OF CLINICALLY ISOLATED NEW QUINOLONES-RESISTANT HAEMOPHILUS INFLUENZAE PART 1

A study was done to determine susceptibilities of Haemophilus influenzae that were obtained in our laboratory in 1994 to new quinolones (NQ) and other drugs. The results were as follows; 1. Among the 300 isolates, the detection frequency of NQ-resistant strains was 8.7%(26 strains), including isolates from chronic lower respiratory tract infections (22 strains) and those from middle meatus of nose (2 strains), etc. NQ-resistant strains were not isolated from children. 2. The cross resistance was studied for different NQs against NQ-resistant strains. Clavulanic acid/amoxicillin, cefteram, cefpodoxime, cefditoren, cefodizime (CDZM) and cefpirome showed strong antimicrobial activities against NQ-resistant strains. MIC90 of CEPs against all isolated strains including NQ-resistant strains and β-lactamase producers was low. And the MIC90 of CDZM was ≤0.025μg/ml, which was the lowest among all the antibiotics tested. 3. We found 47 strains (15.7%) of β-lactamase producers among the 300 isolates, the frequency of β-lactamase producing strains was high among strains obtained from children.