Prevalence of type b Haemophilus influenzae and antibiotic resistance in 52 clinical isolates in north Lebanon.

The aim of this study was to determine the capsular typing and type b prevalence of clinical Haemophilus influenzae strains in north Lebanon in both invasive and non-invasive disease and to determine the susceptibility pattern and the mechanism of resistance to β-lactams [β-lactamase-producing strains and β-lactamase-negative ampicillin resistant (BLNAR) strains]. Fifty-two strains of clinical H. influenzae were isolated from 312 clinical specimens; the resistance pattern to β-lactams of these strains was determined by using the disc diffusion and E-test methods followed by molecular methods such as PCR of blaTEM et blaROB genes. Nine (17.4%) of the 52 strains were resistant to ampicillin; all of them produced type TEM-1 β-lactamase. In the susceptible strains 15.3% were not fully susceptible to β-lactams or considered low BLNAR strains. Slide agglutination serotyping showed that 30.7% of the strains were type b.