BIOTYPES AND SEROTYPES OF HAEMOPHILUS-INFLUENZAE OF CLINICAL ISOLATESFROM MEXICAN CHILDREN

Background: Infectious diseases caused by H. influenzae type b are con sidered preventable through vaccination with Hib conjugate vaccines. S ome countries which follow Hib vaccination programs are close to eradi cation of the disease. In Mexico in particular, little epidemiological information is available. Methods: In this study, 90 clinical strains of H. influenzae were obtained from Mexican children who were treated in four pediatric hospitals in Puebla City, and were diagnosed with i nvasive or localized infectious diseases. The strains were identified by standard bacteriological methods. Biotyping was done by Kilian crit eria and serotyping by coagglutination, Results: H. influenzae infecti ons were found in children younger than 5 years of age, and 68.8% of t he children were younger than 24 months. Sixty percent of the isolates belonged to serotype b, 31.1% were nontypeable, and 7.7% were conside red non-type b, Serotype b was the most frequent isolate associated wi th invasive infectious diseases; however, nontypeable strains were iso lated more frequently from children with otitis, sinusitis, conjunctiv itis, and bronchial secretion, Non-type b serotypes were isolated from invasive and non-invasive infections in few cases. Biotypes I and IV were the most frequent isolates of H. influenzae, Conclusions: This st udy emphasizes the urgent need for an Hib-conjugated vaccine to achiev e immunization in a pediatric population.