Context

Tuberculosis (TB), an airborne infectious disease caused by the bacterium Mycobacterium tuberculosis, is a major cause of illness globally. Tuberculosis is the leading cause of mortality globally due to infectious diseases, causing an estimated 1.23 million deaths in 2024^{Reference 1}. While effective treatments exist, control may be hampered by the emergence of drug resistance. Drug resistance is therefore considered to be a public health threat, notably multidrug-resistant TB (MDR-TB) and resistance to the most effective first-line drug, rifampicin (RR-TB). In 2024, the World Health Organization (WHO) estimated that of the 10.7 million people who fell ill with TB, approximately 3.2% developed MDR-TB or RR-TB^{Reference 1}. As part of Canada’s commitment to eliminate TB, trends and patterns in TB drug resistance are monitored nationally.

For detailed information on the Canadian Tuberculosis Laboratory Surveillance System (CTBLSS), including the specific methods and definitions used in this report, please refer to About the Programs. →

Key findings

• In 2024, the majority of isolates of TB in Canada that underwent susceptibility testing (91.1%) were susceptible to first-line drugs.
• The percentages slightly decreased between 2023 and 2024 for isolates with resistance reported to at least one anti-TB first-line drug (from 11.0% to 8.9%), MDR-TB (from 1.5% to 1.3%), and XDR-TB (from 0.2% to 0.0%).
• The number and proportion of isolates with resistance to at least one anti-TB first-line drug, MDR-TB and XDR-TB in 2024 were within the range observed over the last 10 years.
• The proportion of isolates presenting resistance to at least one first-line drug, mono-resistance, or poly-drug resistance may be underestimated, as 14.5% (n=290) are not submitted for drug-susceptibility testing to pyrazinamide as part of local protocols.
• Drug resistance continues to be low in Canada, with multi-drug resistance remaining rare and below global estimates of 3.2% MDR-TB or RR-TB in 2024^{Reference 1}.
• Previous reports from the Canadian Tuberculosis Reporting System (CTBRS) show that most TB cases with drug resistance were born outside of Canada^{Reference 2}. This underscores the importance of continuing to monitor global rates of drug resistance and ensuring there is prompt detection and treatment of MDR and XDR cases of TB.

Table 1: Definitions of tuberculosis drug-resistance patterns used in this report

Overview of isolates received

In 2024, information about drug susceptibility testing (DST) was available for 2,041 M. tuberculosis isolates submitted from provinces and territories. Of these, 20 isolates were identified as the BCG strain, and one could not undergo drug susceptibility testing and were excluded from further analysis, leaving a total of 2,020 M. tuberculosis complex (MTBC) isolates for analyses (Figure 1). This is the highest number of eligible isolates reported in the past 10 years.

Figure 1: Summary of drug resistance patterns in tuberculosis isolates tested for anti-TB drug susceptibility, CTBLSS 2024

Figure 1: Text Description

Flow chart of the number of Mycobacterium tuberculosis (MTB) isolates tested for drug susceptibility, as reported to the CTBLSS in 2024. A total of 2,041 TB isolates were reported, of which 2,020 were identified as MTBC and subsequently tested for drug susceptibility, while 21 (1.0%) were identified as Mycobacterium bovis BCG strain or could not undergo drug susceptibility testing and were excluded from further analysis. Among MTB isolates, 1,840 (91.1%) were susceptible and 180 (8.9%) were resistant to first line drugs.

The following table summarizes the type of drug resistance identified in 180 isolates with resistance to first line drugs:

Type of drug resistance	Number of MTB isolates	Percentage
Mono-Resistance	148	7.3%
Poly-resistance	6	0.3%
Multidrug-resistance	26	1.3%
Other resistance	0	0.0%

The following table summarizes the type of TB drug resistance in 148 mono-resistant isolates:

Drug type	Number of MTB isolates
Isoniazid	119
Rifampin	3
Pyrazinamide	26
Ethambutol	0

The following table summarizes the type of TB drug resistance in 6 poly-resistant isolates:

Drug type	Number of MTB isolates
Isoniazid and pyrazinamide	3
Isoniazid and ethambutol	3

The following table summarizes the type of TB drug resistance in 26 multidrug-resistant isolates:

Drug type	Number of MTB isolates
Pre-XDR-TB	6
Isoniazid and rifampin	8
Isoniazid and rifampin and pyrazinamide	7
Isoniazid and rifampin and ethambutol	4
Isoniazid and rifampin and ethambutol and pyrazinamide	1

The following table summarizes the type of TB drug resistance in 6 pre-XDR-TB isolates:

Drug type	Number of MTB isolates
Isoniazid and rifampin and at least one fluoroquinolone	1
Isoniazid and rifampin and ethambutol and at least one fluoroquinolone	1
Isoniazid and rifampin and ethambutol and pyrazinamide and at least one fluoroquinolone	4

Of the 6 pre-XDR isolates, 1 were XDR-TB and was resistant to isoniazid, rifampin, ethambutol, pyrazinamide, at least one fluoroquinolone and at least one second-line injectable drug.

Similar to the previous 9 years, the four most populous provinces accounted for the majority (n=1,673; 82.9%) of these isolates: 793 (39.3%) from Ontario, 349 (17.3%) from Quebec, 277 (13.7%) from British Columbia, and 254 (12.6%) from Alberta (Figure 2).

Figure 2: Number Proportion of MTB isolates with reported drug sensitivity, by Canadian jurisdiction and year, CTBLSS, 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015

Figure 2: Text Description

Jurisdiction	Value	2015	2016	2017	2018	2019	2020	2021	2022	2023	2024
Canada	Isolates	1,339	1,451	1,521	1,465	1,627	1,553	1,581	1,687	1,904	2,020
	Proportion (%)	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%
Ontario	Isolates	480	505	557	548	625	574	620	653	735	793
	Proportion (%)	35.8%	34.8%	36.6%	37.4%	38.4%	37.0%	39.2%	38.7%	38.6%	39.3%
British Columbia	Isolates	231	216	265	256	268	281	274	297	323	277
	Proportion (%)	17.3%	14.9%	17.4%	17.5%	16.5%	18.1%	17.3%	17.6%	17.0%	13.7%
Quebec	Isolates	185	218	186	213	244	203	195	223	311	349
	Proportion (%)	13.8%	15.0%	12.2%	14.5%	15.0%	13.1%	12.3%	13.2%	16.3%	17.3%
Alberta	Isolates	185	206	199	161	226	239	198	201	227	254
	Proportion (%)	13.8%	14.2%	13.1%	11.0%	13.9%	15.4%	12.5%	11.9%	11.9%	12.6%
Manitoba	Isolates	129	168	156	149	146	123	146	159	137	181
	Proportion (%)	9.6%	11.6%	10.3%	10.2%	9.0%	7.9%	9.2%	9.4%	7.2%	9.0%
Saskatchewan	Isolates	50	65	64	59	48	67	48	77	87	82
	Proportion (%)	3.7%	4.5%	4.2%	4.0%	3.0%	4.3%	3.0%	4.6%	4.6%	4.1%
Nunavut	Isolates	35	33	60	37	39	27	59	32	44	25
	Proportion (%)	2.6%	2.3%	3.9%	2.5%	2.4%	1.7%	3.7%	1.9%	2.3%	1.2%
Nova Scotia	Isolates	7	3	7	8	6	14	17	15	14	18
	Proportion (%)	0.5%	0.2%	0.5%	0.5%	0.4%	0.9%	1.1%	0.9%	0.7%	0.9%
New Brunswick	Isolates	7	9	9	6	9	8	9	14	12	16
	Proportion (%)	0.5%	0.6%	0.6%	0.4%	0.6%	0.5%	0.6%	0.8%	0.6%	0.8%
Prince Edward Island	Isolates	2	4	0	2	2	2	3	2	5	3
	Proportion (%)	0.1%	0.3%	0.0%	0.1%	0.1%	0.1%	0.2%	0.1%	0.3%	0.1%
Newfoundland and Labrador	Isolates	21	18	8	20	10	7	8	12	4	11
	Proportion (%)	1.6%	1.2%	0.5%	1.4%	0.6%	0.5%	0.5%	0.7%	0.2%	0.5%
Yukon	Isolates	3	2	8	3	1	1	1	0	4	5
	Proportion (%)	0.2%	0.1%	0.5%	0.2%	0.1%	0.1%	0.1%	0.0%	0.2%	0.2%
Northwest Territories	Isolates	4	4	2	3	3	7	3	2	1	6
	Proportion (%)	0.3%	0.3%	0.1%	0.2%	0.2%	0.5%	0.2%	0.1%	0.1%	0.3%

Resistance to first-line drugs

In 2024, 1,840 (91.1%) MTBC isolates tested were susceptible to all first-line drugs tested, while 180 (8.9%) isolates were resistant to at least one first-line drug (Figure 1). Resistance to isoniazid was the most frequently reported (n=151; 7.5% of all MTBC isolates), followed by resistance to pyrazinamide (n=41; 2.0%), rifampin (n=29; 1.4%) and ethambutol (n=13; 0.6%) (Figure 3 and Figure 4). Isoniazid resistance was therefore reported in 83.9% of drug-resistant isolates, while resistance to pyrazinamide, rifampin or ethambutol was reported in 22.8%, 16.1% and 7.2% of resistant isolates, respectively.

Figure 3: Text Description

Resistance to:	Mono-resistance		Multidrug-resistance		Poly-resistance		Other resistance		Overall
	Isolates (n)	Proportion (%)	Isolates (n)	Proportion (%)	Isolates (n)	Proportion (%)	Isolates (n)	Proportion (%)	Isolates (n)	Proportion (%)
Isoniazid	119	78.8%	26	17.2%	6	4.0%	0	0.0%	151	100.0%
Pyrazinamide	26	63.4%	12	29.3%	3	7.3%	0	0.0%	41	100.0%
Rifampin	3	10.3%	26	89.7%	0	0.0%	0	0.0%	29	100.0%
Ethambutol	0	0.0%	10	76.9%	3	23.1%	0	0.0%	13	100.0%
At least 1 first-line drug	148	82.2%	26	14.4%	6	3.3%	0	0.0%	180	100.0%

Notes:

1. Resistance categories (Mono-resistance, Multidrug-resistance, Polydrug-resistance, and other resistance) are mutually exclusive, but resistance to one drug does not exclude resistance to others, i.e. one isolate could be resistant to multiple drugs.
2. Proportions are calculated over the annual total number of MTBC isolates.

The proportion of isolates resistant to at least one first-line drug reported in 2024 is consistent with the proportions observed between 2015 and 2023, between 8.0% and 11.0% (Figure 4).

Figure 4: Number Proportion of MTBC isolates resistant to first-line drugs over time, CTBLSS 2015 - 2024

Figure 4: Text Description

Resistance to:		2015	2016	2017	2018	2019	2020	2021	2022	2023	2024
At least 1 first-line drug	Isolates	139	130	122	148	171	151	157	164	209	180
	Proportion (%)	10.4%	9.0%	8.0%	10.1%	10.5%	9.7%	9.9%	9.7%	11.0%	8.9%
Isoniazid	Isolates	110	113	108	116	140	126	127	135	147	151
	Proportion (%)	8.2%	7.8%	7.1%	7.9%	8.6%	8.1%	8.0%	8.0%	7.7%	7.5%
Pyrazinamide	Isolates	39	26	22	43	43	32	34	44	80	41
	Proportion (%)	2.9%	1.8%	1.4%	2.9%	2.6%	2.1%	2.2%	2.6%	4.2%	2.0%
Rifampin	Isolates	24	18	15	28	23	20	23	27	34	29
	Proportion (%)	1.8%	1.2%	1.0%	1.9%	1.4%	1.3%	1.5%	1.6%	1.8%	1.4%
Ethambutol	Isolates	10	10	10	8	6	8	11	10	14	13
	Proportion (%)	0.7%	0.7%	0.7%	0.5%	0.4%	0.5%	0.7%	0.6%	0.7%	0.6%

Notes

1. Percentages are calculated over the annual total number of MTBC isolates.
2. Categories are not mutually exclusive: resistance to each drug is reported here independently from susceptibility results to the other first-line drugs (the isolate could be resistant to more than one first-line drug, i.e. not mono-resistant).

Mono - and poly-resistance

In 2024, the predominant resistance pattern was mono-resistance, which was detected in 7.3% of all isolates, and 82.2% (n=148) of resistant isolates (n=180) (Figure 3 and Figure 5). Mono-resistance to isoniazid was the more frequent and accounted for 5.9% (n=119) of all isolates, followed by mono-resistance to pyrazinamide (1.3%; n=26), rifampin (0.1%; n=3), and ethambutol (0.0%; n=0). (Figure 3). Out of all the mono-resistant isolates, isoniazid accounted for 80.4%, pyrazinamide for 17.6%, rifampin for 2.0% and ethambutol for 0.0% of mono-resistant isolates, respectively.

Figure 5: Number Proportion of MTBC isolates by resistance patterns over time, CTBLSS 2015 - 2024

Figure 5: Text Description

Resistance to:		2015	2016	2017	2018	2019	2020	2021	2022	2023	2024
Susceptible to first-line drugs	Isolates	1,200	1,321	1,398	1,317	1,455	1,402	1,422	1,522	1,695	1,840
	Proportion (%)	89.6%	91.0%	91.9%	89.9%	89.4%	90.3%	89.9%	90.2%	89.0%	91.1%
Resistance to at least 1 first-line drug	Isolates	139	130	122	148	171	151	157	164	209	180
	Proportion (%)	10.4%	9.0%	8.0%	10.1%	10.5%	9.7%	9.9%	9.7%	11.0%	8.9%
Mono-resistance	Isolates	114	108	101	121	146	128	135	135	165	148
	Proportion (%)	8.5%	7.4%	6.6%	8.3%	9.0%	8.2%	8.5%	8.0%	8.7%	7.3%
Multidrug-resistance	Isolates	19	22	17	14	22	20	15	18	23	29
	Proportion (%)	1.6%	1.2%	0.9%	1.5%	1.2%	1.0%	1.1%	1.4%	1.5%	1.3%
Poly-resistance	Isolates	3	5	6	5	5	7	4	6	11	6
	Proportion (%)	0.2%	0.3%	0.4%	0.3%	0.3%	0.5%	0.3%	0.4%	0.6%	0.3%
Other resistance patterns	Isolates	0	0	1	0	0	1	0	0	4	0
	Proportion (%)	0.0%	0.0%	0.1%	0.0%	0.0%	0.1%	0.0%	0.0%	0.2%	0.0%
Total Isolates	Isolates	1,339	1,451	1,521	1,465	1,627	1,553	1,581	1,687	1,904	2,020
	Proportion (%)	100.0%	100.0%	100.0%	100.0%	100.0%	100.0%	100.0%	100.0%	100.0%	100.0%

Notes

1. Percentages are calculated over the total annual number of MTBC isolates.
2. Categories are not mutually exclusive.
3. “Other resistance patterns” include resistance patterns that are not one of the previously defined resistance patterns (resistance to more than (i) one drug excluding RMP, and (ii) MDR/TB, see figure 1).

Multidrug-resistance and rifampin-resistance

Rifampin-resistance (RR-TB), including multidrug-resistance (MDR-TB), has been of growing concern to human health globally as it poses a threat to the overall strategy of controlling or eliminating TB. Resistance to rifampin, defined as resistance to rifampin with or without resistance to other first-line anti-TB drugs, and also reported as MDR-TB/RR-TB, was detected in 1.4% (n=29) of MTBC isolates reported in 2024 (Figure 5 and Figure 6). This is consistent and within the range recorded in the last 10 years (Figure 5).

Multidrug-resistance was the second most frequently reported resistance pattern; it was found in 14.4% (n=26) of drug-resistant isolates (Figure 1 and Figure 3), corresponding to 1.3% of all (n=2,2020) isolates reported in 2024 (Figure 3). Approximately 23.1% (n=6) of these multidrug-resistant isolates also exhibited resistance to at least one fluoroquinolone and as such, were considered pre-extensively drug-resistant (pre-XDR), while 3.8% (n=1) demonstrated an additional resistance to a fluoroquinolone, and to any second-line injectable drug (Figure 1) and was therefore extensively drug-resistant (XDR-TB). The number of pre-XDR has been relatively stable and very low: from a couple of isolates per year from 2015 to 2017 to six isolates per year in the last three years (Figure 6). XDR-TB has been very rare and detected sporadically only in two isolates between 2015 and 2022, but it was detected for the first time in four isolates in one year in 2023. One isolate was XDR-TB in 2024 (Figure 6).

Figure 6: Number Proportion of MTBC isolates with multidrug-resistance and rifampin-resistance over time, CTBLSS 2015 - 2024

Figure 6: Text Description

Multidrug- and Rifampin-resistance		2015	2016	2017	2018	2019	2020	2021	2022	2023	2024
All RR-TB	Isolates	24	18	15	28	23	20	23	27	34	29
	Proportion (%)	1.8%	1.2%	1.0%	1.9%	1.4%	1.3%	1.5%	1.6%	1.8%	1.4%
All MDR-TB	Isolates	22	17	14	22	20	15	18	23	29	26
	Proportion (%)	1.6%	1.2%	0.9%	1.5%	1.2%	1.0%	1.1%	1.4%	1.5%	1.3%
Pre-XDR-TB	Isolates	1	2	2	4	3	5	3	6	6	6
	Proportion (%)	0.1%	0.1%	0.1%	0.3%	0.2%	0.3%	0.2%	0.4%	0.3%	0.3%
XDR-TB	Isolates	0	0	0	1	0	0	1	0	4	1
	Proportion (%)	0.0%	0.0%	0.0%	0.1%	0.0%	0.0%	0.1%	0.0%	0.2%	0.0%
Total Isolates	Isolates	1,339	1,451	1,521	1,465	1,627	1,553	1,581	1,687	1,904	2,020
	Proportion (%)	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%

Notes

1. Percentages are calculated over the annual total number of MTBC isolates.
2. The resistance patterns in this table are not mutually exclusive.

Drug resistance by age and sex

Sex

Overall in 2024, the majority of MTBC isolates were from male individuals (57.2%; n=1,155), as were isolates with resistance to at least one first-line drug. MDR-TB/RR-TB and XDR-TB were found more frequently in isolates from female individuals (62.1%, n=18 and 100%, n=1 respectively) in the overall total, but the trend was inverted in some age groups (Figure 7). Given the limited number of resistant isolates, no marked differences could be found according to sex in multidrug-resistant or extensively drug-resistant isolates (Figure 7).

Age

About 98.9% (n=178) of isolates resistant to first-line anti-TB drugs were detected in individuals older than 14 years of age, with the 25–34 years and 35-44 years age group having the largest proportion (23.9%; n=43 and 22.8%, n=41 respectively). No resistance to any first-line drug was found in isolates from children less than 5 years of age.

Most MDR-TB/RR-TB isolates (72.4%; n=21) were detected in 15–44 year-olds, and the extensively drug-resistant isolate was found in the 15–24 years age group (Figure 7). These trends have been consistent overall over the last decade (data not shown).

Figure 7: Number Proportion of MTBC isolates by age and resistance pattern, among both sex female male cases, CTBLSS 2024

Figure 7: Text Description

Age Group	Sex	All Isolates		Resistance to at least one first-line drug		MDR-TB/RR-TB		XDR-TB
		Isolates (n)	Proportion (%)	Isolates (n)	Proportion (%)	Isolates (n)	Proportion (%)	Isolates (n)	Proportion (%)
< 5 years old	Female	1	0.1%	0	0.0%	0	0.0%	0	0.0%
	Male	12	1.0%	0	0.0%	0	0.0%	0	0.0%
	Both sexes	13	0.6%	0	0.0%	0	0.0%	0	0.0%
5–14 years old	Female	22	2.6%	2	2.5%	1	5.6%	0	0.0%
	Male	15	1.3%	0	0.0%	0	0.0%	0	0.0%
	Both sexes	37	1.8%	2	1.1%	1	3.4%	0	0.0%
15–25 years old	Female	146	17.1%	9	11.4%	7	38.9%	1	100.0%
	Male	162	14.0%	11	11.0%	1	9.1%	0	0.0%
	Both sexes	308	15.3%	20	11.1%	8	27.6%	1	100.0%
25–34 years old	Female	215	25.1%	18	22.8%	3	16.7%	0	0.0%
	Male	246	21.3%	25	25.0%	2	18.2%	0	0.0%
	Both sexes	461	22.9%	43	23.9%	5	17.2%	0	0.0%
35–44 years old	Female	137	16.0%	20	25.3%	5	27.8%	0	0.0%
	Male	181	15.7%	21	21.0%	3	27.3%	0	0.0%
	Both sexes	318	15.8%	41	22.8%	8	27.6%	0	0.0%
45–54 years old	Female	94	11.0%	12	15.2%	1	5.6%	0	0.0%
	Male	130	11.3%	19	19.0%	3	27.3%	0	0.0%
	Both sexes	224	11.2%	31	17.2%	4	13.8%	0	0.0%
55–64 years old	Female	83	9.7%	8	10.1%	1	5.6%	0	0.0%
	Male	131	11.3%	11	11.0%	0	0.0%	0	0.0%
	Both sexes	214	10.6%	19	10.6%	1	3.4%	0	0.0%
65+ years old	Female	158	18.5%	10	12.7%	0	0.0%	0	0.0%
	Male	278	24.1%	13	13.0%	2	18.2%	0	0.0%
	Both sexes	436	21.6%	23	12.8%	2	6.9%	0	0.0%
All age groups	Female	856	100%	79	100%	18	100%	1	100%
	Male	1,164	100%	101	100%	11	100%	0	0%
	Total	2,020	100%	180	100%	29	100%	1	100%

Notes

1. The sex of 9 individuals was missing and were excluded from graphs stratified by sex.l
2. Percentages are presented among the number of isolates by resistance pattern.

Drug resistance by province and territory

In 2024, resistance to first-line drugs was not found in isolates from Yukon, Northwest Territories, Nunavut and Prince Edward Island. Similar to the distribution of all isolates, most isolates with resistance to at least one of the first-line drugs (86.1%; n=155), mono-resistance (85.8%; n=127), polydrug-resistance (83.3%; n=5) and MDR-TB/RR-TB (86.2%; n=25), were from the four most populous provinces (Ontario, Quebec, British Columbia and Alberta) (Figure 8). XDR-TB was more frequently reported by Ontario (n=4), British Columbia (n=2) and Saskatchewan (n=1) over the last 10 years.

Trends of resistance by province and territory have been constant overall in the last decade, with the majority of resistant isolates originating from the four most populous provinces (data not shown).

Figure 8: Number Proportion of MTBC isolates by jurisdiction and resistance pattern, CTBLSS 2024

Figure 8: Text Description

Jurisdiction	All Isolates		Resistance to at least one first-line drug		MDR-TB/RR-TB		XDR-TB
	Isolates (n)	Proportion (%)	Isolates (n)	Proportion (%)	Isolates (n)	Proportion (%)	Isolates (n)	Proportion (%)
Canada	2,020	100%	180	100%	29	100%	1	100%
Alberta	254	12.6%	31	17.2%	6	20.7%	0	0.0%
British Columbia	277	13.7%	31	17.2%	3	10.3%	0	0.0%
Manitoba	181	9.0%	13	7.2%	3	10.3%	0	0.0%
New Brunswick	16	0.8%	1	0.6%	0	0.0%	0	0.0%
Newfoundland and Labrador	11	0.5%	1	0.6%	0	0.0%	0	0.0%
Nova Scotia	18	0.9%	1	0.6%	1	3.4%	0	0.0%
Northwest Territories	6	0.3%	0	0.0%	0	0.0%	0	0.0%
Nunavut	25	1.2%	0	0.0%	0	0.0%	0	0.0%
Ontario	793	39.3%	63	35.0%	12	41.4%	1	100.0%
Prince Edward Island	3	0.1%	0	0.0%	0	0.0%	0	0.0%
Quebec	349	17.3%	30	16.7%	4	13.8%	0	0.0%
Saskatchewan	82	4.1%	9	5.0%	0	0.0%	0	0.0%
Yukon	5	0.2%	0	0.0%	0	0.0%	0	0.0%

References

More information

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