Antibiotic susceptibility and molecular analysis of invasive Haemophilus influenzae in Canada, 2007 to 2014.

Background: Previously we studied the antibiotic susceptibility of invasive Haemophilus influenzae collected in Canada from 1990 to 2006 and characterized isolates by serotype, MLST and ftsI gene sequencing for significant PBP3 mutations. Objectives: To provide an update based on isolates collected from 2007 to 2014. Methods: A total of 882 case isolates were characterized by serotype using slide agglutination and PCR. MLST was carried out to determine ST. Isolates were tested for beta-lactamase production, presence of significant PBP3 mutations and antibiotic susceptibility by disc diffusion against 14 antibiotics. MIC values of three antibiotics were determined for 316 isolates using microbroth dilution. Results: Non-typeable H. influenzae accounted for 54.6% of the isolates and 45.4% were serotypeable, predominantly type a (23.1%), type b (8.3%) and type f (10.8%). The overall rate of ampicillin resistance due to beta-lactamase production was 16.4% and increased from 13.5% in 2007-10 to 19% in 2011-14. Significant PBP3 mutations were identified in 129 isolates (14.6%) with 23 (2.6%) also producing beta-lactamase. MLST identified related STs (ST-136, ST-14 and
Auteurs (Zotero)
Tsang, Raymond S. W.; Shuel, Michelle; Whyte, Kathleen; Hoang, Linda; Tyrrell, Gregory; Horsman, Greg; Wylie, John; Jamieson, Frances; Lefebvre, Brigitte; Haldane, David; Gad, Rita R.; German, Gregory J.; Needle, Robert
Date de publication (Zotero)
mai, 2017