The objective of this study was to compare the proportion of invasive and respiratory tract isolates of Streptococcus pneumoniae (SPN), including multidrug/extensive-drug resistant (MDR/XDR) strains, that demonstrated PCV15/PPSV23 serotypes in Canada from 2007-2018.
The CANWARD study collected 2821 SPN isolates from 2007-2018 (986 invasive, 1835 respiratory). Serotyping was performed by the Quellung reaction. Antimicrobial susceptibility testing was performed using CLSI methods. MDR/XDR was defined as resistance to ³3/³5 antimicrobial classes, respectively.
Overall, the proportion of blood isolates demonstrating a PCV15/PPSV23 serotype was significantly higher than respiratory strains (55.4/76.7% vs 39.5/55.3%, P<0.0001). By age group, with the exception of the <2-year category, the proportion of blood isolates demonstrating a PCV15/PPSV23 serotype was significantly higher than respiratory strains (P</=0.0046). Similar results were noted by gender (P<0.0001) and region (P</=0.0002), with the exception of Eastern Canada. There was no significant difference in the proportion of MDR blood (64.4/71.1%) and respiratory (54.3/56.1%) isolates representing PCV15/PPSV23 serotypes, respectively. All XDR isolates were serotypes contained in PCV15/PPSV23, and there was no significant difference in proportion between blood (92.9%) and respiratory (88.9%) isolates.
In general, the proportion of blood isolates demonstrating a PCV15/PPSV23 serotype in Canada was significantly higher than that of respiratory isolates.