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Role of inter-species recombination of the ftsI gene in the dissemination of altered penicillin-binding-protein-3-mediated resistance in Haemophilus influenzae and Haemophilus haemolyticus
Methods:The ftsI genes of 100 Haemophilus isolates comprising genetically defined β-lactamase-negative ampicillin-susceptible (gBLNAS), β-lactamase-positive ampicillin-resistan (gBLPAR), β-lactamase-negative ampicillin-resistant (gBLNAR) and β-lactamase-positive amoxicillin/clavulanate-resistant (gBLPACR) isolates of NTHi (n = 50) and H. haemolyticus (n = 50) were analysed in this study. Both the flanking regions and the full-length ftsI gene sequences of all study isolates were screened for mosaic structures using H. influenzae Rd and H. haemolyticus ATCC 33390 as reference parental sequences, and bioinformatics methods were used for recombination analysis using SimPlot.
Results:Of the 100 clinical isolates analysed 34% (34/100) harboured mosaic ftsI gene structures containing distinct ftsI gene fragments similar to both reference parental sequences. The inter-species recombination events were exclusively encountered in the ftsI gene of gBLNAR/gBLPACR isolates of both NTHi and H. haemolyticus, and were always associated with the formation of a mosaic fragment at the 3′ end of the ftsI gene. There was no evidence supporting horizontal gene transfer (HGT) involving the entire ftsI gene among the clinical isolates in vivo.
We provide evidence for the HGT and inter-species recombination of the ftsI gene among gBLNAR/gBLPACR isolates of NTHi and H. haemolyticus in a clinical setting, highlighting the importance of recombination of the ftsI gene in the emergence of altered penicillin-binding protein 3 and BLNAR-mediated resistance.
Clifford Craig Foundation
Publication titleJournal of Antimicrobial Chemotherapy
Department/SchoolSchool of Health Sciences
PublisherOxford Univ Press
Place of publicationGreat Clarendon St, Oxford, England, Ox2 6Dp
Rights statementCopyright 2014 Oxford University Pr