[Epidemiological characterization of Haemophilus influenzae using molecular markers]

Abstract

Background: Haemophilus influenzae is the etiological agent of acute- (meningitis, sepsis, pneumonia, epiglottis) and chronic infections (cystic fibrosis, chronic obstructive pulmonary infections). Several clinical (chronic infections) and epidemiological situations (community and hospital outbreaks) require the use of epidemiological typing methods.

Objective: We evaluated four typing methods to characterize clinical isolates of H. influenzae.

Methods: Forty-five clinical strains of H. influenzae were studied by biotype, serotype and antibiotype techniques, and the following methods: isoenzyme electrophoresis mobility, outer membrane proteins (OMP), ribotyping and pulsed field gel electrophoresis (PFGE).

Results: Type b strains had one pattern with Isoenzyme, OMP and ribotyping techniques. Only PFGE enabled us to differentiate between several type b patterns, although all of them were close related. All methods showed a great variety of patterns with the non-typable H. influenzae although clinical- or epidemiological-related strains had identical patterns.

Conclusions: Results obtained with all four markers studied showed good agreement. Type b strains, in contrast to non-typable strains, had a strong clonal structure with all the assayed techniques; only PFGE showed differences. In terms of technical and financial cost, as well as reproducibility and discriminative power, we suggest as a markers for H. influenzae OMP and PFGE.