Tuberculosis: Drug resistance in Canada, 1998

Reported susceptibility results of the Canadian Tuberculosis Laboratory Surveillance System

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TABLE OF CONTENTS

INTRODUCTION
METHODOLOGY
RESULTS
FIGURES
Figure 1.	Reported MTB isolates in Canada by province/territory - 1998
Figure 2.	Overall pattern of reported TB drug resistance in Canada - 1998
Figure 3.	Reported TB drug resistance in Canada by type of drug - 1998
Figure 4.	Percentage of TB drug resistance in Canada by sex and year of birth - 1998
TABLES
Table 1.	Reported MTB isolates by "reporting" and "originating" province/territory, Canada - 1998
Table 2.	Overall pattern of reported TB drug resistance in Canada - 1998
Table 3.	Reported MDR-TB isolates by province/territory, Canada - 1998
Table 4.	Reported TB drug resistance by sex and year of birth, Canada - 1998
Table 5.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, Alberta - 1998
Table 6.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, British Columbia - 1998
Table 7.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, Manitoba - 1998
Table 8.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, New Brunswick - 1998
Table 9.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, Newfoundland - 1998
Table 10.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, Northwest Territories - 1998
Table 11.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, Nova Scotia - 1998
Table 12.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, Ontario - 1998
Table 13.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, Prince Edward Island - 1998
Table 14.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, Québec - 1998
Table 15.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, Saskatchewan - 1998
Table 16.	Reported results for routine sensitivity testing of MTB isolates to first-line antituberculosis drugs, Yukon Territory - 1998
LIMITATIONS
APPENDICES
Appendix 1 -	Participating Laboratories of the Canadian Tuberculosis Laboratory Technical Network (CTLTN)
Appendix 2 -	M. tuberculosis Complex Antimicrobial Susceptibility Reporting Form

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INTRODUCTION

The Division of Tuberculosis Prevention and Control in the Bureau of HIV/AIDS, STD and TB at the Laboratory Centre for Disease Control (LCDC), Health Canada, in collaboration with the Canadian Tuberculosis Laboratory Technical Network (CTLTN) (Appendix 1), established a laboratory based national surveillance system in 1998 in order to monitor tuberculosis drug resistance patterns in Canada. Participating laboratories (representing all provinces and territories) report their results on Mycobacterium tuberculosis (MTB) drug sensitivity testing to the Division for every patient for whom a specimen or an isolate has been received for each calendar year. The Division subsequently analyzes the collected data on an ongoing basis and has agreed to produce, as a minimum, an annual report. This initial report presents the 1998 results on drug sensitivity data received as of June 9, 1999.

METHODOLOGY

A computerized database containing information on drug susceptibility patterns is maintained at the Division of Tuberculosis Prevention and Control at LCDC, Health Canada. The data were collected either through the manual completion and mailing of a standard reporting form (Appendix 2) or the electronic transmission of the data to the Division. Information collected include gender, year of birth, province/territory from which the report originates, province/territory from which the specimen originates and sensitivity results. Every effort was made to eliminate duplicate specimens. For the purposes of analysis, only the most recent sensitivity results for a given patient are included.

Routine sensitivity testing of MTB to first-line antituberculosis drugs is generally performed using the radiometric proportion method (Bactec®). These first-line drugs include isoniazid (INH), rifampin (RMP), ethambutol (EMB), streptomycin (SM) and pyrazinamide (PZA). Routine testing for SM is not conducted for isolates from Nova Scotia and Prince Edward Island. For isolates from Saskatchewan, British Columbia and the Yukon Territory, routine testing is not performed for PZA. Second-line drug resistance was not examined in this report.

Because of the variations in routine sensitivity testing, descriptive analyses of the testing results have been conducted to reflect the various drugs tested. Analyses were performed using Epi-Info 6.04 and SAS 6.12.

RESULTS

In 1998, 1,423 M. tuberculosis isolates were reported across Canada. Of these, 168 (11.8%) were resistant to one or more first-line TB drug(s). Resistance to INH was the most common type of drug resistance (8.4%). Multi-drug resistant tuberculosis (MDR-TB) (defined as resistance to at least to INH and RMP) accounted for 1.2% of the isolates.

Ontario and Quebec reported the majority of isolates and had the highest percentage of MDR-TB. Certain provinces (New Brunswick, Nova Scotia) reported only INH resistance, while others (Newfoundland, Prince Edward Island, Northwest Territories, Yukon Territory) reported isolates that were sensitive to all first-line TB drugs tested.

Demographic information on patients was limited. Resistant MTB isolates were evenly distributed between males and females; more were found in those born between 1941 and 1980.

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Figure 1
Reported MTB isolates in Canada by province/territory - 1998 (n = 1,423)

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Figure 2
Overall pattern of reported TB drug resistance in Canada - 1998 (n = 168)

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Figure 3
Reported TB drug resistance in Canada by type of drug - 1998 (n = 168)

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Figure 4
Percentage of TB drug resistance in Canada by sex and year of birth - 1998 (n = 168)

 

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HOW TO REACH US

For more information, copies of this report or other reports, please contact:

Tuberculosis Prevention and Control
Centre for Infectious Disease Prevention and Control
Public Health Agency of Canada
Health Canada
Room 0108 B, Brooke Claxton Building
Tunney's Pasture, Ottawa, Ontario K1A 0K9

Internal Postal Address: 0900B-1

Telephone: (613) 941-0238
Facsimile: (613) 946-3902

The following text, figures and tables were prepared by:

Penny Nault
Tuberculosis Database Manager
Tuberculosis Prevention and Control

Melissa Phypers, MSc
A/Chief
Tuberculosis Prevention and Control

ACKNOWLEDGEMENT

Tuberculosis Prevention and Control would like to acknowledge the members of the Canadian Tuberculosis Laboratory Technical Network and their teams for their contribution to and their participation in the Canadian Tuberculosis Laboratory Surveillance System (CTBLSS).

Published by authority of the Minister of Health

© Her Majesty the Queen in Right of Canada, represented by the Minister of Public Works and Government Services Canada, 2002.

Cat. H49-110/2001
ISBN 0-662-66495-7

This publication can be made available in alternative formats.