Jpn. J. Infect. Dis., 59 (2), 111-116, 2006
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Original Article
Genetic and Phenotypic Characterization of Haemophilus influenzae Type b Isolated from Children with Meningitis and Their Family Members in Vietnam
Phan L. T. Huong*, Ngo T. Thi1, Dang D. Anh, Vu T. T. Huong, Le N. Minh2, Tran Q. Canh3, Mayumi Matsuoka4, Kazunari Kamachi4, Tsutomu Yamazaki5, Yoshichika Arakawa4 and Tsuguo Sasaki4
Department of Bacteriology and 2Department of Immunology & Biotechnology, National Institute of Hygiene and Epidemiology; 1Department of Microbiology, National Hospital fo Pediatric, Hanoi; 3Hai Duong Medical College, Haiduong Province, Vietnam; 4Department of Bacterial Pathogenesis and Infection Control, National Institute of Infectious Diseases, Tokyo 208-0011; and 5Department of Pediatrics, Saitama Medical School, Saitama 350-0495, Japan
(Received December 26, 2005. Accepted February 21, 2006)
*Corresponding author: Mailing address: Department of Bacteriology, National Institute of Hygiene and Epidemiology, 1 Yersin Street, Hanoi, Vietnam. Tel: +84-4-9714408, Fax: +84-4-8210853, E-mail: thanhhuong@hn.vnn.vn
SUMMARY: To investigate Haemophilus influenzae type b (Hib) infection in Vietnamese children under the age of 5 years, cerebrospinal fluid (CSF) samples from patients with meningitis were screened for Hib, and isolates were subjected to evaluation of susceptibility to 12 antibiotics, biotyping, and genotyping with pulsed-field gel electrophoresis (PFGE). The major biotype was type II (68.3%), followed by type I (22.8%). Among 79 Hib isolates, 45 (57%) were beta-lactamase-producing and ampicillin-resistant (44 and 1 isolates produced TEM-1- and ROB-1-type beta-lactamases, respectively), and 34 isolates (43%) were beta-lactamase-nonproducing and ampicillin-sensitive. No beta-lactamase-nonproducing and ampicillin-resistant isolates were found. The PFGE patterns of Hib isolates were highly divergent, but most could be classified into three clusters. We also investigated Hib colonization in household contacts of patients, and found that Hib isolates from the CSF of patients and from nasopharyngeal cavities of household contacts showed the same PFGE patterns. This observation suggested that household contacts of patients are a possible reservoir of Hib.