Antibacterial agents resistance and typing of ?-lactamases in moraxella catarrhalis / 中华检验医学杂志

ABSTRACT

Objective To distinguish BRO ?-lactamase by use of restriction endonuclease analysis and investigate antibacterial agents resistance of Moraxella catarrhalis(M. Catarrhalis) with different BRO ?-lactamases .Methods Nasopharyngeal swabs of children with respiratory tract infections from the outpatient department of Beijing Children's Hospital were cultured for isolating M.Catarrhalis. BSAC(british society for antimicrobial chemotherapy) agar diffusion test was used to determine antibacterial agents resistance of M.Catarrhalis.Nitrocefin disk was used to detect ?-lactamase. Restriction endonuclease analysis was used to distinguish BRO ?-lactamases . Antibacterial agents resistance of M. Catarrhalis with different bro genes was compared.Results (1)95.0% of the 80 strains were beta-lactamase positive. MIC 90 of ampicillin was 32 ?g/ml and MIC 90 of cefuroxime,cefaclor and cefotaxime were 4 ?g/ml,8?g/ml and 1?g/ml respectively,MIC 90 of tetracycline was 16?g/ml. Among the antibacterial agents,ciprofloxacin was the most sensintive agent.(2)Among 80 strains,6(7.5%) Strains were bro negative,55(68.8%) were bro-1 positive,19(23.8%)were bro-2 positive。Except 2 strains,the results of ?-lactamases were same as the results of nitrocefin disk and restriction endonuclease analysis.(3)Compared with bro-2 positive strains,the MIC value of ampicillin and cefaclor for bro-1 positive strains were higher.Conclusions Antibacterial agents resistance of M. Catarrhalis to ampicillin was sierous in China. It should be strengthened to monitor antibacterial agents resistance of M.Catarrhalis. Restriction endonuclease analysis can play an important role on characterizing bro genes,evaluating antibacterial agents resistance of Moraxella Catarrhalis to ?-lactam and investigating molecular epideminology