Clonal diversity of Haemophilus influenzae carriage isolated from under the age of 6 years children

OBJECTIVES: Pharyngeal carriers such as H. influenzae seem to constitute the only reservoir and probably the only transmission vehicle of the invasive disease. The aims of this study were to estimate the prevalence of H. influenzae carriage, to characterize antibiotic susceptibility, and to explore genetic diversity of H. influenzae isolates. Sampling was carried out as nasopharynx swabs among children less than 6 years old volunteers. After traditional biochemical tests, isolates were confirmed by targeting omp6 sequence. Following the susceptibility tests, genomic diversity of strains was analyzed by Pulsed-Field Gel Electrophoresis procedure. RESULTS: Out of 328 nasopharynx swabs, 73 strains were identified as H. influenzae. Among H. influenzae isolates, resistance to chloramphenicol (42%) and ampicillin (43%) was observed. Levofloxacin is the most effective antibiotic and the least effect belonged to tetracycline. By genomic analysis of selected H. influenza, 28 PFGE patterns were achieved among which 11 patterns included at least 2 strains. All strains clustered into 25 different clones. The dendrogram analysis of the isolated H. influenzae strains showed that some of these strains had a clonal relationship and common genetic origin. According to our results, antibiotic resistance didn’t show any significant correlation with the clonality of strains.