Variation in selected regions of blaTEM genes and promoters in Haemophilus influenzae

Objectives: To determine if the TEM β-lactamases of Haemophilus influenzae are TEM-1 or derivatives thereof and associated exclusively with the overlapping Pa/Pb promoters. Methods: Single nucleotide specific PCR was used to discriminate the polymorphic nucleotides at positions 32 and 317 of the blaTEM genes of a collection of TEM-positive strains. Results: All blaTEM genes were found to be blaTEM-1 or derivatives thereof and none blaTEM-2 The blaTEM genes were associated with the P3 promoter, the Pa/Pb promoters or a novel promoter produced as a result of a 135 bp deletion and a G162T substitution. Conclusions: The genetic features of blaTEM genes in H. influenzae are different from those in Enterobacteriaceae and more variable than previously recognized. © The Author 2005. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.