Abstract: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 β-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 β-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.［Chin J Contemp Pediatr, 2009, 11 (3):217-220］
