In Vitro Antimicrobial Susceptibilities of Streptococcus pneumoniae Clinical Isolates Obtained in Canada in 2002

Abstract

Empirical treatment is best guided by current surveillance of local resistance patterns. The goal of this study is to characterize the prevalence of antimicrobial nonsusceptibility within pneumococcal isolates from Canada. The Canadian Bacterial Surveillance Network is comprised of laboratories from across Canada. Laboratories collected a defined number of consecutive clinical and all sterile site isolates of S. pneumoniae in 2002. In vitro susceptibility testing was performed by broth microdilution with NCCLS guidelines. Rates of nonsusceptibility were compared to previously published reports from the same network. A total of 2,539 isolates were tested. Penicillin nonsusceptibility increased to 15% (8.5% intermediate, 6.5% resistant) compared to 12.4% in 2000 (P < 0.025, 2 ). Only 32 (1.3%) isolates had an amoxicillin MIC of >4 g/ml and only 2 of 32 cerebrospinal fluid isolates had an intermediate susceptibility to ceftriaxone by meningeal interpretive criteria (MIC ‫؍‬ 1 g/ml). A total of 354 (13.9%) isolates were macrolide nonsusceptible (46.3% MLS B , 56.7% M phenotype), increasing from 11.4% in 2000 (P < 0.0075, 2 ). Only 13 (<1%) isolates had a telithromycin MIC of >1 g/ml. Ciprofloxacin nonsusceptibility (defined as an MIC of >4 g/ml) increased to 2.7% compared to 1.4% in 2000 (P < 0.0025, 2 ) and was primarily found in persons >18 years old (98.5%). Nonsusceptibility to penicillin, macrolides, and fluoroquinolones is increasing in Canada. Nonsusceptibility to amoxicillin and ceftriaxone remains uncommon. Newer antimicrobials such as telithromycin and respiratory fluoroquinolones have excellent in vitro activity.

Susceptibility of Streptococcus pneumoniae to Fluoroquinolones in Canada

“…The Canadian Bacterial Surveillance Network is comprised of private and hospital-affiliated laboratories from across Canada and provides service to community and tertiary care hospitals, community clinics, physician offices, and long-term care facilities (25). All 10 Canadian provinces and two of three territories are represented.…”

Antimicrobial Activity of Oleanolic Acid from Salvia officinalis and Related Compounds on Vancomycin-Resistant Enterococci (VRE)

“…4) VRE has been first reported in U.K. and France in 1986. 5) In the case of the United States, the percentage of VRE in enterococci isolated from ICUs was 0.4% in 1989, but it increased up to 28.5% in 2003.…”

Antimicrobial Susceptibility of Invasive and Lower Respiratory Tract Isolates of Streptococcus pneumoniae, 1998 to 2007

“…Rates of antimicrobial nonsusceptibility continue to be relatively low and stable when compared with data from other parts of Canada and other countries (11,12,14,(22)(23)(24). Penicillin nonsusceptibility at 8% overall is one of the lowest reported rates in the modern era, with amoxicillin faring even more favourably with 0.3% intermediate susceptibility.…”

“…Les isolats prélevés sur des enfants de moins de cinq ans étaient plus susceptibles d'être multirésistants et résistants à l'érythromycine et à la céfotaxime. Il est important d'assurer une surveillance continue des isolats de S pneumoniae parce que, dans les régions sanitaires, les taux de résistance varient selon la source et l'âge des patients resistance rates of 19% in Atlantic Canada, 14% to 16% in Central Canada, and 12% to 18% in Western Canada (14).…”