Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 7 3 2015 11 25 136 143 EN Somayeh Bagherzadeh-Khodashahri M.Sc. Student, Department of Microbiology, Kerman Science and Research Branch, Islamic Azad University, Kerman, Iran. Seyed Davar Siadat Department of Mycobacteriology & Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran. Mohammad Rahbar Department of Microbiology, Reference Health Laboratories Research Center, Ministry of Health and Medi- cal Education, Tehran, Iran. Meghdad Abdollahpour-Alitappeh Department of Immunology, Pasteur Institute of Iran, Tehran, Iran. Farzam Vaziri Department of Mycobacteriology & Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran. Mrjan Rahnamaye-Farzami Department of Laboratory Tecnhnology, Reference Health Laboratories Research Center, Ministry of Health and Medical Education, Tehran, Iran. Mona Mohammadzadeh Department of Microbiology ,Milad Hospital ,Tehran, Iran. Mehdi Davari Department of Mycobacteriology & Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran. Abolfazl Fateh Department of Mycobacteriology & Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran. Morteza Masoumi Department of Mycobacteriology & Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran. 2015 11 24 Background and Objective: Haemophilus influenzae type b (Hib) is divided into two distinct genotypes, type I and type II, based on the structure of capsular polysaccharides. The capsulation locus of Haemophilus influenzae type b consists of three functionally distinct regions, designated regions 1 to 3. Region III contains hcsA and hcsB genes; however, notable sequence variation in this region can be used to recognize different Hib genotypes. The purpose of this study was to investigate the prevalence and genotype of the Hib strains isolated from patients with invasive disease in Iran. Materials and Methods: In the present study, 8 pairs of primers were used for identification and serotyping of encapsulated Haemophilus influenzae strains, as well as confirmation of species identification. Additionally, in order to identify the cap- sular genotypes of Haemophilus influenzae type b (type I and II), two additional primer pairs were used to amplify the hcsA gene. Results: Out of 50 isolates of H. influenzae, four were found to be type b. Interestingly, among these 4 Hib isolates, 2 strains belonged to the type-II category. Conclusion: Our study shows that the prevalence of both Hib types I and II seems to be high in Iran. https://ijm.tums.ac.ir/index.php/ijm/article/view/813 https://ijm.tums.ac.ir/index.php/ijm/article/download/813/498