Preamble: 2008 Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) annual report

Preamble

About CIPARS

The Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS), created in 2002, is a national program dedicated to the collection, integration, analysis, and communication of trends in antimicrobial use and resistance in selected bacteria from humans, animals, and animal-derived food sources across Canada. This information supports (i) the creation of evidence-based policies for antimicrobial use in hospitals, communities, and food-animal production with the aim of prolonging the effectiveness of these drugs and (ii) the identification of appropriate measures to contain the emergence and spread of resistant bacteria among animals, food, and people. This publication represents the 7th annual CIPARS report released by the Government of Canada under the coordination of the Public Health Agency of Canada.

CIPARS Objectives

• Provide a unified approach to monitor trends in antimicrobial resistance and antimicrobial use in humans and animals.
• Disseminate timely results.
• Generate data to facilitate assessment of the public health impact of antimicrobials used in humans and agricultural sectors.
• Provide data that allow accurate comparisons with data from other countries that use similar surveillance systems.

CIPARS 2008 Activities

In 2008, CIPARS included 2 passive and 3 active antimicrobial resistance surveillance components, as well as antimicrobial use surveillance in humans and animals (Figure 1).

Surveillance of Antimicrobial Resistance

• Surveillance of Human Clinical Isolates involved passive surveillance of human clinical Salmonella isolates at the provincial/territorial level and participation of all Provincial Public Health Laboratories across the country.
• Retail Meat Surveillance involved active sample collection and antimicrobial susceptibility testing of generic Escherichia coli, ^{Footnote 4} Enterococcus, Salmonella, and Campylobacter in retail chicken, and of E. coli in beef and Salmonella and E. coli in pork from British Columbia, Saskatchewan, Ontario, Québec, and the Maritimes region (New Brunswick, Nova Scotia, and Prince Edward Island). Campylobacter and Enterococcus isolates recovered from retail chicken in the Maritimes region underwent antimicrobial susceptibility testing, but results are not presented in this report because of concerns surrounding harmonization of laboratory methods for 2008 only.
• Abattoir Surveillance involved active sample collection of ceacal content and antimicrobial susceptibility testing of Salmonella and generic E. coli of healthy chickens and pigs and of Campylobacter and generic E. coli from healthy beef cattle across Canada.
• Farm Surveillance involved swine herds in the 5 major pork-producing provinces in Canada (Alberta, Saskatchewan, Manitoba, Ontario, and Québec). A sentinel farm framework was used to organize the active collection of pooled fecal samples from pigs and the isolation of generic E. coli, Enterococcus, and Salmonella isolates for antimicrobial susceptibility testing.
• Surveillance of Animal Clinical Isolates involved passive surveillance of clinical Salmonella isolates from animals in multiple provinces. Samples were originally submitted by veterinarians or producers to local or provincial laboratories and may have also included samples from animal feed, the animal's environment, or non-diseased animals from the same herd. Cattle isolates could be from either dairy or beef cattle, or from veal farms. Chicken isolates could be from either layer hens or broiler chickens.
• Salmonella isolates recovered from Feed and Feed Ingredients samples were obtained from Government and Industry Monitoring programs and from passive surveillance.

Surveillance of Antimicrobial Use

• Antimicrobial use surveillance in humans included data obtained from the Canadian CompuScript and provided by Intercontinental Medical Statistics Health for 2000 through 2008. This dataset contains information on prescriptions dispensed by Canadian retail pharmacies.
• Antimicrobial use surveillance in pigs included data obtained from the Farm Surveillance component of CIPARS through questionnaires completed by veterinarians, owners, or managers of the herds. Questionnaires captured information on antimicrobials used (in water, feed, and injections) within each herd, health status of pigs, and farm characteristics.
• Antimicrobial use surveillance in animals included data obtained from the Canadian Animal Health Institute and analysed by Impact Vet for 2006 through 2008. This dataset contains information on the total kilograms of antimicrobials distributed by Canadian companies for use in food, sporting, and companion animals and fish.

Figure 1. - Click to enlarge

What's New in the 2008 Report

Changes to CIPARS

• Retail Meat Surveillance began in the Maritimes region in September 2008.

Methodological Changes

• A more sensitive Campylobacter recovery method than was previously used was implemented for bacterial culture of caecal samples from abattoir beef cattle.
• The new resistance breakpoint of 4 µg/mL for ceftriaxone (Clinical and Laboratory Standards Institute [CLSI] M100-S20) was adopted and applied to the final 2008 Salmonella and E. coli data and all historical data. The previous breakpoint was 64 µg/mL. This change resulted in an increase in ceftriaxone resistance to levels now similar to those of ceftiofur resistance. In terms of reporting, we therefore no longer present results on intermediate susceptibility to ceftriaxone.
• Since the release of the 2008 preliminary CIPARS report, the revised version (April 2009) of the classification system of the Veterinary Drugs Directorate (VDD), Health Canada was adopted. This change resulted in the reclassification of quinupristin-dalfopristin as a Category II antimicrobial (High Importance in Human Medicine) instead of a Category I antimicrobial (Very High Importance in Human Medicine) for all Enterococcus isolates.

Periodic Reporting

• Antimicrobial resistance results are presented for Salmonella retail pork isolates received from 2003 through 2008.

Important Notes

Antimicrobial Groupings

• Category of importance in human medicine: Antimicrobials have been categorized on the basis of importance in human medicine in accordance with the classification system of the VDD, Health Canada (categories revised in April 2009; Appendix A). All Category I antimicrobials (Very High Importance in Human Medicine) are highlighted throughout the report. These antimicrobials include amoxicillin-clavulanic acid, ceftiofur,Footnote 6 ceftriaxone, ciprofloxacin, daptomycin, linezolid, telithromycin, and vancomycin. Antimicrobials are generally listed first according to this classification and then alphabetically.
• ATC class: For human antimicrobial use data, antimicrobials have been classified by the international standard Anatomic Therapeutic Chemical (ATC) class system^{Footnote 7} in addition to the category of importance in human medicine.
• Canadian Animal Health Institute aggregate class: Data on the distribution of antimicrobial use in animals were provided to CIPARS by the Canadian Animal Health Institute in aggregate antimicrobial classes as presented in this report.

Labels and Particular Highlights Regarding Certain Antimicrobials

• "Reduced susceptibility": Reduced susceptibility to ciprofloxacin^{Footnote 8} is highlighted in this report. It was defined as a minimal inhibitory concentration (MIC)^{Footnote 5} from 0.125 to 2 μg/mL for Salmonella and E. coli.
• "Non-susceptible": For daptomycin and florfenicol, the term "non-susceptible" is used instead of "resistant" because these antimicrobials do not have a referenced resistance breakpoint (Appendix B).
• "Selected antimicrobials": In the temporal variations analyses, the selected antimicrobials were chosen to represent the different antimicrobial structural classes (for the complete list of exclusion criteria, please see Appendix A). For Salmonella and E. coli isolates, selected antimicrobials included ampicillin, ceftiofur, gentamicin, nalidixic acid, streptomycin, tetracycline, and trimethoprim-sulfamethoxazole. For Campylobacter isolates, selected antimicrobials included azithromycin, florfenicol, gentamicin, nalidixic acid, and tetracycline. For Enterococcus isolates, selected antimicrobials included ciprofloxacin, erythromycin, gentamicin, quinupristin-dalfopristin, streptomycin, tetracycline, and tylosin. It should be noted that resistance to these antimicrobials does not necessarily imply equal resistance to other antimicrobials from the same class.
• Resistance to nalidixic acid (a quinolone) is highlighted for Salmonella and E. coli. Additionally, we have highlighted isolates with reduced susceptibility or resistance to ciprofloxacin (a fluoroquinolone) but no resistance to nalidixic acid.^{Footnote 10} These latter isolates may have different genetic determinants of resistance than isolates with both nalidixic acid resistance and reduced susceptibility or resistance to ciprofloxacin.
• Joint reduced susceptibility to ciprofloxacin (or resistance to nalidixic acid) and resistance to ceftriaxone, a third generation cephalosporin, is also highlighted for Salmonella or E. coli.

Additional Notes

• Temporal variations: In general, temporal variations in the percentage of isolates resistant to selected antimicrobials were identified by comparing results for 2008 with those for 2003 (the year most surveillance components of CIPARS began) and those for the previous year (2007). For data regarding retail surveillance in Saskatchewan, 2005 was the first year of surveillance.
• For data on ceftiofur and ampicillin resistance in S. Heidelberg and E. coli isolates obtained from chicken (abattoir and retail) and S. Heidelberg isolates from humans, the years of comparison were 2004 and 2006 because of changes in ceftiofur use in early 2005^{Footnote 9} and in 2007 in chicken hatcheries in Québec. For retail chicken, comparisons using those reference years were limited to the provinces of Ontario and Québec.
• Temporal variations in Surveillance of Animal Clinical Isolates and Feed and Feed Ingredients data were not tested because the intensity of passive surveillance was unequal across years.
• In the statistical analyses of temporal variations in the percentages of isolates resistant to selected antimicrobials and of differences among provinces, a value of P ≤ 0.05 was used to indicate a significant difference between years and among provinces.
• With the exception of Enterococcus faecalis and E. faecium, no attempt was made to identify the species of Enterococcus recovered from CIPARS samples. Unidentified species of enterococci are collectively referred to in this report as "other Enterococcus spp." However, when used alone, the term "Enterococcus" refers to all enterococci, including E. faecalis and E. faecium. Similarly, Campylobacter coli and C. jejuni were the only species of Campylobacter that were specifically identified; unidentified species are collectively referred to as "other Campylobacter spp." When used alone, the term "Campylobacter" refers to all species of Campylobacter, including C. coli and C. jejuni.
• Antimicrobial abbreviations used in this report are defined in Appendix D.