Distribution of serotypes, biotype, and antibiotic sensitivity of Haemophilus influenzae in nasopharyngeal carrier children in Lima, Peru.

After the introduction of the Hib (Haemophilus influenzae type b) vaccine, invasive infection caused by this bacterium markedly decreased; however, concern increased regarding the other typable and non-typable strains (NTHi). Prior colonization with this pathogen can become a source of invasive infection. This study aimed to determine colonization by H. influenzae in 888 healthy children under 24 months of age. Colonization was 4.1% (37 samples) using molecular methods (all NTHi) and 1.1% (10 isolates) by culture (8/10 biotype I and 2/10 biotype IV). A history of prematurity was associated with higher colonization in multivariate analysis. Of the isolates, 9/10 were resistant to sulfamethoxazole/trimethoprim, 3/10 to ampicillin and cefuroxime, 2/10 to azithromycin, and no resistance to ceftriaxone was observed. Understanding the carriage status of H. influenzae and local resistance patterns is useful for empirical antibiotic therapy in invasive infections where this bacterium is suspected.