British Columbia Medical Journal, May 2010 issue Please download or visit this entire issue online at http://bcmj.org/may-2010

1. bc centre for
disease control
Update on antibiotic resistance in British Columbia
Dustin Li, Rachel McKay, MSc,
Dale Purych, BSc, MD, FCFP,
100%
Percent of isolates
FRCPC, David M. Patrick, MD,
FRCPC, MHSc
50%
his article highlights recent
T trends in antimicrobial resis-
tance of key bacterial patho-
gens. These findings represent a brief Erythromycin
0%
1999
85.1%
2002
93.9%
2005
94.9%
2007
94.2%
2008
90.5%
2009
89.2%
overview of the BCCDC’s 2010 Clindamycin 76.0% 82.9% 42.0% 37.7% 39.0% 35.7%
Antimicrobial Resistance Trends re- TMP-SMX 70.9% 79.0% 15.6% 5.9% 7.5% 4.7%
port.1 Bacterial organisms that are
monitored for non-susceptibility in
the report include methicillin-resis- Figure 1. Percent of MRSA non-susceptible to clindamycin, erythromycin, and TMP-SMX.
tant (MRSA) and methicillin-suscep-
tible (MSSA) Staphylococcus aureus,
Streptococcus pneumoniae, Strepto-
coccus pyogenes, Enterococcus spp., 35%
Escherichia coli, Klebsiella pneumo- 30%
Percent of isolates
niae, Proteus mirabilis, Pseudomonas 25%
aeruginosa, Salmonella Enteriditis, 20%
Haemophilis influenzae, Neisseria
15%
meningitides and Neisseria gonor-
rhoeae. 10%
5%
Findings 0%
Bacterial pathogens in British Colum- 1999 2002 2005 2007 2008 2009
bia continue to display important Erythromycin 6.1% 6.0% 16.1% 29.1% 27.3% 32.0%
changes to their resistance profile. The Clindamycin 2.0% 2.0% 8.1% 16.9% 11.3% 18.9%
main trends of current relevance:
• Methicillin-resistant Staphylococ-
cus aureus (MRSA) represents ap- Figure 2. Percent of S. pnemoniae isolates resistant to erythromycin and clindamycin.
proximately one-quarter of all tested
S. aureus isolates in 2009. MRSA
resistance toward erythromycin, pneumoniae isolates have demon- • Enterococcus spp. isolates remain
clindamycin, and trimethoprim- strated increasing resistance against highly susceptible to ampicillin,
sulfamethoxazole (TMP-SMX) has erythromycin over the past decade. vancomycin, and nitrofurantoin
seen a steady decline ( Figure 1 ) like- In 1999, the percent of S. pneumoni- (> 98%). One-quarter (25.2%) of all
ly attributed to the increased preva- ae isolates that exhibited resistance isolates remain ciprofloxacin resis-
lence of community-associated (CA) toward erythromycin was 6.1%, but tant, although significant decreases
MRSA strains. Moreover, MRSA this figure has increased dramatical- in resistance have occurred since
isolates have displayed significantly ly to 32.0% as of 2009. Clindamycin 2002, when 47% were resistant. The
higher resistance rates than MSSA resistance rates have also increased percentage of Enterococcus spp. iso-
isolates to these other agents. among S. pneumoniae over the past lates demonstrating resistance against
• Data from BC Biomedical Labora- decade, from 2.0% in 1999 to 18.9% vancomycin has remained under 1%
tories indicate that Streptococcus in 2009 ( Figure 2 ). in BC for years 1999 to 2009.
226 BC MEDICAL JOURNAL VOL. 52 NO. 4, MAY 2010 www.bcmj.org

2. cdc
traint in prescribing can slow and even
stop emergence of some resistance
Restraint in prescribing can slow and patterns that would otherwise increase
morbidity, mortality, and health care
even stop emergence of some resistance
costs. The full 2010 report will be
patterns that would otherwise increase posted at www.bccdc.ca/util/about/
morbidity, mortality, and health care costs. annreport/default.htm.
Acknowledgments
We would like to thank BC Biomedical Lab-
oratories and all contributors to the 2010
report.
• Urinary tract pathogens such as highest prescription drug class. Source: BC Biomedical Laboratories
Escherichia coli, Klebsiella pneu- Tetracyclines are the third most Reference
moniae and Proteus mirabilis have prescribed antibacterial group and 1. Epidemiology Services, BC Centre for
demonstrated increasing resistance have seen little fluctuation in the Disease Control. Antimicrobial Resis-
against ciprofloxacin while only E. past 5 years. Fluoroquinolones and tance Trends in the Province of British
coli and P. mirabilis isolates have trimethoprim/sulfonamides are the Columbia—March 2010. www.bccdc.ca/
seen increasing resistance in TMP- fifth and sixth most prescribed anti- util/about/annreport/default.htm
SMX. Nitrofurantoin remains highly bacterials in BC, with the former (accessed 1 April 2010).
effective for E. coli with over 96% displaying a steady increase driven
of isolates showing susceptibility. by the drug ciprofloxacin and the Mr Li is an undergraduate student in Health
• Antimicrobial utilization rates have introduction of new respiratory flu- Information Sciences at University of Vic-
remained stable over the last 3 years. oroquinolones. toria. Ms McKay is a surveillance analyst at
Although β-lactam antibacterials the Epidemiology Services at the BC Cen-
continue to be the most prescribed Why is antimicrobial tre for Disease Control (BCCDC). Dr Purych
drug class in BC, utilization rates resistance surveillance is a medical microbiologist at BC Biomed-
along with those for trimethoprim/ necessary? ical Laboratories Ltd and Fraser Health, and
sulfonamides have seen noticeable Knowledge of current antimicrobial a clinical instructor of pathology and labo-
decreases since 1996. Macrolides/ resistance trends informs targeted and ratory medicine at UBC. Dr Patrick is the
clindamycin have seen a dramatic empirical therapy. Findings under- director of Epidemiology Services at the
increase in utilization since 1998 score the critical value of appropriate BCCDC and professor in the School of Pop-
and combined are now the second- antibiotic use and stewardship. Res- ulation and Public Health at UBC.
Upcoming articles in the BCMJ — June and July/August 2010
Thank you Dr Benton:
Implantable cardioverter-defibrillator— The rationale for using a
From Mirowski to its current use surgical checklist in British Columbia
(Dyell, Tung, & Ignaszewski) (Cochrane & Lamsdale)
Does an Aspirin a day
keep the doctor away? Tularemia in British Columbia:
Acetylsalicylic acid for the primary A case report and review
prevention of cardiovascular disease (Hoang & Isaac-Renton)
(Bayliss & Ignaszewski)
www.bcmj.org VOL. 52 NO. 4, MAY 2010 BC MEDICAL JOURNAL 227