Ribotyping, Biotyping and Capsular Typing of Haemophilus influenzae Strains Isolated from Patients in

Forty-five Haemophilus influenzae strains isolated from patients were characterized based on biochemical characteristics. Their capsular types were determined by polymerase chain reaction (PCR); they were compared, using two molecular methods [ribotyping with a specific DNA probe amplified from the 16S rDNA region from H. influenzae and through restriction fragment length polymorphism (RLFP) of an amplified 16S DNA region]. The strains were better discriminated by the ribotyping technique that used the 16S probe and by the combination of both techniques. Biotypes I and IV were the most common, followed by biotypes VI, VIII and III. Biotypes II and VII were not found. Most of the capsular samples were nontypable (89%), with capsular types a and b found in 2 and 9% of the samples, respectively. We concluded that there is a very close genetic identity among pathogenic and non-pathogenic strains. Key-Words: Haemophilus influenzae, characterization, ribotyping, serotype, biotype. Haemophilus influenzae, a commensal pleomorphic Gram-negative bacillus found in the human upper respiratory tract, has been associated with localized and invasive infections, such as bronchitis, otitis, pneumonia, meningitis, septicemia, and epiglottitis [1]. Systemic diseases are normally caused b