Antibiotic Susceptibility of Haemophilus influenzae in Sfax: Two Years after the Introduction of the Hib Vaccination in Tunisia

Abstract

A retrospective study was conducted at the Sfax hospitals between 2013 and 2014 to study the susceptibility to antibiotics of Haemophilus influenzae after the introduction of Hib vaccination in Tunisia. Capsular typing was done by PCR. MICs for β-lactams were determined by E-test®. The blaTEM, blaROB and ftsI genes were searched using PCR. Among the 259 strains of H. influenzae isolated, 248 (95.7%) were non-invasive. Five strains were encapsulated (3 type b and 2 type c). Resistance rates were 33.4% for ampicillin, 10.4% for amoxicillin-clavulanic acid, 2.3% for cefixime, 1.1% for cefotaxime and 1.9% for fluoroquinolones. Among the strains resistant to β-lactams, 67 produced β-lactamase type TEM and 40 had a modification of PLP3. This study shows the change in the epidemiology of H. influenzae induced by vaccination with a dramatic decrease of invasive infections. Replacement with other capsular types or with non-typable strains that may be resistant to antibiotics requires continuous surveillance for H. influenzae infections.