Characterisation of Novel ß-lactamase genes in Haemophilus influenzae

H. influenzae can produce either TEM-1 or ROB-1 ß-lactamases. The gene for the TEM-1 is most commonly encoded on large integrated conjugative elements (ICE) and less commonly on small poorly characterised cytoplasmic plasmids. There have been four recent reports of ß-lactamase positive strains negative for both TEM-1 and ROB-1 by PCR, with apparent novel ß-lactamases.