bla ROB-1 Presence on pB1000 in Haemophilus influenzae Is Widespread, and Variable Cefaclor Resistance Is Associated with Altered Penicillin-Binding Proteins

Abstract

ABSTRACT Plasmid pB1000 is a small replicon recently identified as bearing bla ROB-1 in animal and human Pasteurellaceae in Spain. We identified pB1000 in 11 bla ROB-1 -positive Australian and North American Haemophilus influenzae isolates, suggesting a wider role for pB1000 in disseminating bla ROB-1 . Native H. influenzae conjugative elements can mobilize plasmids similar to pB1000 at a low frequency of 10 −8 , and this might account for the infrequency of bla ROB-1 compared to the rate of occurrence of bla TEM-1 . Altered penicillin-binding protein 3 was associated with an increased cefaclor MIC in 3 isolates.