| Objective:To investigate the antibiotics-resistance patterns and serotypes of Haemophilus influenzae in vitro isolated from children with respiratory infection in Hangzhou.Methods:Isolates were identified withⅤfactor andⅩfactor test.Nitrocefin test was used to detectβ-lactamase.The sensitivities of 12 antibiotics against Haemophilus influenzae were determined with Kirby-Bauer diffusion methods and MICs of ampicillin were determined with E-test method.Serotypes were determined with slide agglutination method.Results:A total of 152 strains of Haemophilus influenzae were collected during the period from December 2006 to June 2007.Thirty-five strains(23.0%) wereβ-lactamase-positive.114 strains(74.3%) were sensitive to ampicillin with E-test method,7 strains(4.6%) were intermediate and 32 strains(21.1%) were ampicillin-resistant, the MIC50 and MIC90 of ampicillin were 0.25μg/ml and 14.80μg/ml respectively.All strains were sensitive to ceftriaxone,amoxicillin/clavlanic acid, sulbactam and cefopcrazone,imipenem.The sensitivity rate to cefotaxime,rifampin, cefaclor,chloramphenicol,clarithromycin,tetracycline and trimethoprim-sulfamethoxazol were 99.3%,97.4%,94.7%,83.6%,82.9%,76.8%and 32.9% respectively.Thirty-five strains(23.0%) were multi-resistant isolates,the multi-resistance rate inβ-lactamase-positive strains were significantly higher than that inβ-lactamase-negative strains(χ2=56.13,P＜0.05).Of the 152 strains isolated from children,141(94.6%) strains were non-typable,while 8 strains(5.2%) were typable and 2.6%of them belonged to type e,type d and type f was 1.3%,respectively,none of type b was found in our study.Conclusion:Non-typable Haemophilus influenzae is the most common type in clinical strains isolated from children in Hangzhou.The resistant rate to ampicillin is increasing.The resistant rate to trimethoprim- sulfamethoxazol is the highest among the 12 antibiotics.We should choice the appropriate antibiotic according to antimicrobial susceptibility test. |
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