Haemophilus influenzae Strains in Tunisian Children

Haemophilus influenzae, a major pathogen causing respiratory tract infections and meningitis, is becoming increasingly resistant to narrow spectrum penicillin. Investigating the reasons for this resistance is challenging.

The sequences of the ftsI gene, encoding the transpeptidase domain of penicillin binding protein (PBP3), were determined for 44 strains of Haemophilus influenzae with reduced susceptibility to β-lactam antibiotics. Strains, isolated from children, were analyzed for genetic relationship by pulsed-field gel electrophoresis (PFGE).

Sequence analysis of the ftsI gene revealed different mutations. We used this polymorphism to classify the different strains into three groups: (I (n=3), II (n=36, including H. influenzae ATCC 49247), this group was divided into four subgroups and III (n=5)). In each group various substitutions were observed.

The increasing number of Haemophilus influenzae strains with reduced susceptibility to β-lactam due to mutations in the ftsI gene, is becoming a serious health issue in Tunisia. The resistance to β-lactam was observed in both strains that produce β-lactamase and those that do not. The level of resistance is remarkably high in our country.