Genotypic versus phenotypic characterization, with respect to beta-lactam susceptibility, of Haemophilus influenzae isolates exhibiting decreased susceptibility to beta-lactam resistance markers.
Sevillano D, Giménez MJ, Cercenado E, Cafini F, Gené A, Alou L, Marco F, Martínez-Martínez L, Coronel P, Aguilar L.
Among 165 Spanish Haemophilus influenzae isolates with mutations in the ftsI gene (ftsI(+)) (2005 to 2007), 73% were beta-lactamase negative and 26.7% were positive. The proportion of beta-lactamase-negative isolates to beta-lactamase-positive isolates was 2:1 to 4:1 in general, versus 1:3 in pediatric hospitals. Among 44 beta-lactamase-positive strains, 8 strains produced ROB-1 (5 from the pediatric hospital). beta-Lactamase-positive ftsI(+) strains were phylogenetically closer than were beta-lactamase-negative strains.