Molecular Characterization and resistance of H. influenzae isolated from Nasopharynx of Students in North Lebanon

Abstract

Introduction: Haemophilus influenzae is an important cause of respiratory infections,including acute otitis media, sinusitis, and chronic bronchitis, which arepreceded by asymptomatic H. influenzae colonization of the human pharynx. Theaim of this study is to investigate the rate of H.influenzae nasopharyngeal colonizationamong students ages 2 to 3 years.Material and methods: A total of 21 isolates of clinical H. influenzae wereisolated from 87 nasopharyngeal specimens of children between April and June2011. The isolates were identified by using molecular techniques (PCR), biotypeswere determined by using the following tests: ornithin decarboxylase, urease andtryptophanase, and capsular typing was performed by SAST by using polyclonaland specific b antisera (Difco-BD®-USA).The prevalence of β -lactams resistance, β-lactamase production, the level of macrolideresistance was recorded for each strain by using disc diffusion and E-teststrip methods and chromogenic cephalosporin test (cefinase). β -lactams resistancegenes (blaTEM and blaROB) were determined using PCR.Results: 42.8 % of the H. influenzae isolates were type b, and biotypes I, II andIII were the majority, whereas biotypes IV, VI and VIII was not found. The majorityof capsule type b was belonged to biotype II. Antibiotics susceptibility showedthat 19% of the isolates were resistant to ampicillin and produced type TEM-1β-lactamase.Conclusion: This study shows the carriage rate of H. influenzae in North Lebanonchildren. The incidence of resistance rate of 19% to ampicillin signals an importantwarning to the future prophylaxis use of beta-lactam in treatment of H. influenzaeinfections in Lebanon