[Serotypes and ampicillin resistance of Haemophilus influenzae isolates from children with respiratory infection in Hangzhou].

OBJECTIVE

To investigate the serotypes distribution and ampicillin resistance of Haemophilus influenzae isolates from children with respiratory infection in Hangzhou.

METHODS

Haemophilus influenzae strains were identified with V factor and X factor tests. Serotypes were determined with the slide agglutination method. Nitrocefin test was used to detect beta-lactamase. The sensitivities of ampicillin to Haemophilus influenzae were determined with the Kirby-Bauer diffusion method and the E-test method.

RESULTS

One hundred and fifty-two Haemophilus influenzae isolates, 108 from boys and 44 from girls, were identified between December 2006 and July 2007. Of the 152 isolates, 148 (97.4%) were untypable, only 4 (2.6%) were typable, including type a, type d, type e and type f (n=1 each type). Haemophilus influenzae type b and c strain was not found. Thirty-four isolates (22.4%) were beta-lactamase-positive. One hundred and thirteen isolates (74.3%) were susceptible to ampicillin, while 34 isolates (22.4%) were resistant to ampicillin.

CONCLUSIONS

Untypable strains were the most common in Haemophilus influenzae isolates from children with respiratory infection in Hangzhou. The isolates of Haemophilus influenzae kept susceptibity to ampicillin to a certain extent.