Trends in Outpatient Bacteremia in British Columbia, Canada between 2010-2015

Background: Understanding the epidemiology of etiologic organisms that cause bacteremia in the community setting is important for treatment and prevention strategies. In British Columbia, Lifelabs Medical Laboratories receives specimens submitted for blood culture from 128 community collection sites distributed across the province. We explored the trends in outpatient blood cultures in British Columbia between 2010 and 2015.

Methods:

Blood cultures drawn at community based Lifelabs collection sites between 2010-2015 were included in the study. Cultures and identification were performed according to routine laboratory methods. Basic demographic information including age, gender, and organism cultured were collected. Antibiotic resistant organisms included methicillin resistant Staphylococcus aureus (MRSA), vancomycin resistant Enterococcus faecalis or  faecium (VRE), ciprofloxacin resistant Salmonella sp., extended spectrum beta lactamase (ESBL) positive Enterobacteriaceae and carbapenem resistant Enterobacteriaceae (CRE).

Results: Between 2010- 2015, a total of 16,619 sets of blood cultures were drawn, for an average sampling rate of 60.56 per 100,000 population. Of the total of 16,619 sets of blood cultures, 342 sets (2.05%) were considered to be significant isolates. The 66 sets of contaminants (0.04%) included predominantly coagulase negative staphylococci (CNS). The eight most common organisms constituted 85.3% of the total positive isolates. Among these organisms, there was no significant change in proportion between 2010- 2015. Both Salmonella sp. and Streptococcus pneumoniae showed a proportional decrease with age (p= <0.008), while Klebsiella pneumoniae showed a proportional increase with age (p= <0.001). No VRE or CRE were noted, while 30.4% of Salmonella sp. were ciprofloxacin resistant, 17.4% of Enterobacteriaceae were ESBL positive, and 6.45% of Staphylococcus aureus were MRSA.

Conclusion:

When analyzed over a 6- year period, there were no significant changes in the proportion of identified organisms. The proportion of antibiotic resistant organism in the community is low.