Section 1: 2008 Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) annual report – Antimicrobial resistance

Section One – Antimicrobial Resistance

Humans

Salmonella

Throughout 2008, the Provincial Public Health Laboratories forwarded a total of 3,609 Salmonella isolates (170 serovars) to the National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba for phage typing, serotyping, and antimicrobial susceptibility testing (see Appendix A – Methods, Antimicrobial Resistance). No Salmonella isolates were identified as having been submitted by the territories (Yukon, Northwest Territories, or Nunavut) to CIPARS in 2008, directly or through Public Health Laboratories. There were duplicate submissions or records for 8 isolates; consequently, final analysis was conducted on 3,601 isolates.

Summary results are provided for the 3 most commonly isolated Salmonella serovars in Canada (Enteritidis, Heidelberg, and Typhimurium). Salmonella Newport also receives attention because of past outbreaks involving multidrug-resistant strains. Although the agri-food sector is not a source of Salmonella Typhi, S. Paratyphi A, or S. Paratyphi B,^{Footnote 12} data for these serovars are also presented because they each cause severe disease in humans.^{Footnote 11}

Antimicrobial resistance results are presented by province because of differences in isolate submission protocols between more populated and less populated provinces (Appendix A – Methods). Results are also presented by province because of variation among provinces in antimicrobial use and in prevailing strains and antimicrobial resistance patterns of Salmonella.

Because isolation of Salmonella from blood or urine specimens suggests patients had an invasive infection that was likely treated with antimicrobials, particular attention was paid to isolates from these specimen sources. Such specimens may have been submitted because of treatment failure, which could not be verified because patient records were not available. Therefore, isolates recovered from these specimens were potentially more likely to be resistant to multiple antimicrobials than isolates from other types of specimens.

Compared with percentages in other age groups, the greatest percentage of Salmonella isolates was from human patients aged 30 to 49 years (25%, 654/2,594; Table C.1, Appendix C). Ontario was the province from which the largest percentage of isolates was received (37%, 1,337/3,601).

Salmonella Enteritidis
(n = 1,258)

Provincial incidence rates for Salmonella Enteritidis detection in humans varied from 4.37 to 10.06 (median = 6.60) cases per 100,000 inhabitant-years (see Appendix A for formula). The most common phage types (PTs) were PT 8 (35%, 444/1,258) and PT 13 (17%, 208/1,258). Three percent (33/1,258) of isolates were recovered from blood, and 2% (21/1,258) were recovered from urine (Table C.2, Appendix C).

Antimicrobial Resistance: Results are presented in Table 1 and Table B.1, Appendix B. Less than 1% (3/1,258) of the S. Enteritidis isolates were resistant to amoxicillin-clavulanic acid. Resistance to ceftiofur and resistance to ceftriaxone were each detected in less than 1% (2/1,258). Reduced susceptibility to ciprofloxacin was detected in 14% (171/1,258) of the isolates. Resistance to nalidixic acid was detected in 13% (158/1,258). None of the isolates were resistant to ciprofloxacin or amikacin.

Antimicrobial Resistance Patterns: Results are presented in Table 8 and Tables C.3 and C.4, Appendix C. Resistance to 1 or more antimicrobials was detected in 14% (182/1,258) of S. Enteritidis isolates. Resistance to 5 or more antimicrobials was detected in 1% (7/1,258). The most common resistance pattern was NAL (11%, 136/1,258), and 59% (80/136) of the associated isolates were PT 1. One percent (14/1,258) of isolates (PT 5b and PT 4) had reduced susceptibility to ciprofloxacin but were not resistant to nalidixic acid. The patterns involving the greatest number of antimicrobials among isolates were A2C-AMP-CRO-STR-TET and AKSSuT-GEN-NAL (1 PT 6a each).

Twenty-seven percent (9/33) of blood isolates and 24% (5/21) of urine isolates were resistant to 1 or more antimicrobials. The most common resistance pattern was NAL, which was found in 12% (4/33) of blood and 19% (4/21) of urine isolates.

Temporal Variations: Results are presented in Figure 2. The percentage of S. Enteritidis isolates with resistance to nalidixic acid was significantly lower in 2008 (13%, 158/1,258) than in 2003 (19%, 66/352). The percentage of isolates with resistance to nalidixic acid in 2008 was also significantly lower than in 2007 (18%, 167/910). The percentage of isolates with resistance to trimethoprim-sulfamethoxazole was significantly lower in 2008 (less than 1%, 5/1,258) than in 2003 (1%, 5/352). The percentage of isolates with resistance to tetracycline was significantly lower in 2008 (2%, 20/1,258) than in 2007 (6%, 58/910). Between 2008 and 2003 and between 2008 and 2007, there were no other significant temporal variations in the percentages of isolates resistant to the selected antimicrobials.

Salmonella Heidelberg
(n = 290)

Provincial incidence rates for Salmonella Heidelberg detection in humans varied from 0.70 to 3.62 (median = 1.67) cases per 100,000 inhabitant-years. The most common phage types were PT 19 (54%, 157/290), PT 29 (8%, 24/290), and PT 5 (8%, 22/290). Twelve percent (34/290) of isolates were cultured from blood, and 2% (6/290) were cultured from urine (Table C.2, Appendix C).

Antimicrobial Resistance: Results are presented in Table 2 and Table B.2, Appendix B. Resistance to amoxicillin-clavulanic acid was detected in 13% (39/290) of S. Heidelberg isolates. Resistance to ceftiofur and ceftriaxone were each detected in 14% (41/290) of isolates. No isolates were resistant to ciprofloxacin, amikacin, or nalidixic acid. None had reduced susceptibility to ciprofloxacin.

Antimicrobial Resistance Patterns: Results are presented in Table 8 and Tables C.3 and C.4, Appendix C. Resistance to 1 or more antimicrobials was detected in 38% (111/290) of S. Heidelberg isolates. Resistance to 5 or more antimicrobials was detected in 14% (41/290). The most common resistance pattern was AMP (14%, 42/290). This resistance pattern was mainly detected among PT 19 isolates (93%, 39/42) and most of those isolates were from Ontario (46%, 18/39) and Québec (41%, 16/39). The pattern involving the greatest number of antimicrobials among isolates was ACKSSuT-A2C-CRO-SXT (1 PT 21).

Forty-four percent (15/34) of blood isolates and 2 of 6 urine isolates were resistant to 1 or more antimicrobials. The most common resistance pattern, AMP, was detected in 18% (6/34) of blood isolates (PT 19) and in no urine isolates.

Temporal Variations: Results are presented in Figure 2. The percentage of S. Heidelberg isolates with resistance to ceftiofur was significantly lower in 2008 (14%) than in 2004 (33%, 181/556).^{Footnote 13} Similarly, the percentage of isolates with resistance to ampicillin was significantly lower in 2008 (32%, 92/290) than in 2006 (39%, 168/430) and 2004 (45%, 250/556). The percentages of isolates with resistance to streptomycin and tetracycline were significantly lower in 2008 (7% [20/290] and 6% [18/290], respectively) than in 2003 (12% [72/608] and 15% [93/608], respectively). Between 2008 and 2003 and between 2008 and 2007, there were no other significant temporal variations in the percentages of isolates resistant to the selected antimicrobials.

Salmonella Newport
(n = 177)

Provincial incidence rates for Salmonella Newport detection in humans varied from 0 to 1.69 (median =  0.66) cases per 100,000 inhabitant-years. There were no reported cases in Prince Edward Island. The most common phage types recovered from samples were PT 9 (22%, 39/177) and phage types designated as atypical (16%, 29/177). Six percent (11/177) of the isolates were cultured from urine, and 4% (7/177) were cultured from blood (Table C.2, Appendix C).

Antimicrobial Resistance: Results are presented in Table 3 and Table B.3, Appendix B. Resistance to amoxicillin-clavulanic acid was detected in 1% (2/177) of S. Newport isolates, and ceftiofur and ceftriaxone resistance were each detected in 2% (3/177). Reduced susceptibility to ciprofloxacin and resistance to nalidixic acid were each detected in 1% (2/177) of isolates. None of the isolates were resistant to ciprofloxacin or amikacin.

Antimicrobial Resistance Patterns: Results are presented in Table 8 and Tables C.3 and C.4, Appendix C. Resistance to 1 or more antimicrobials was detected in 5% (9/177) of S. Newport isolates. Resistance to 5 or more antimicrobials was detected in 2% (4/177). The most common resistance patterns were TET (1%, 2/177), which was detected in 1 PT 9 and 1 PT 14c isolate, and ACSSuT-A2C-CRO (1%, 2/177), which was detected in 1 PT 17a and 1 PT 17c isolate. The pattern involving the greatest number of antimicrobials among isolates was ACSSuT-A2C-CRO (1 PT 17a and 1 PT 17c), which was also among the most common resistance patterns. None of the isolates from blood or urine were resistant to 1 or more antimicrobials.

Temporal Variations: Results are presented in Figure 2. The percentages of S. Newport isolates with resistance to ceftiofur or ampicillin were significantly lower in 2008 (2% and 3% [5/177], respectively) than in 2003 (10% [17/175] and 13% [22/175], respectively). The percentages of isolates with resistance to streptomycin and tetracycline were also significantly lower in 2008 (2% [4/177] and 4% [7/177], respectively) than in 2003 (10% [17/175] and 13% [22/175], respectively). Between 2008 and 2003 and between 2008 and 2007, there were no other significant temporal variations in the percentages of isolates resistant to the selected antimicrobials.

Salmonella Paratyphi A and Paratyphi B
(n = 65)

The combined provincial incidence rates for Salmonella Paratyphi A and Salmonella Paratyphi B^{Footnote 14} detection varied from 0 to 0.91 (median = 0.18) cases per 100,000 inhabitant-years. No cases were reported in New Brunswick, Prince Edward Island, or Newfoundland and Labrador. Phage typing is not applicable to S. Paratyphi A isolates. Among the 12 isolates of S. Paratyphi B, phage types included atypical (9/12), Battersea (2/12), and Worksop (1/12). Sixty-four percent (34/53) of S. Paratyphi A isolates were cultured from blood, and 2% (1/53) were cultured from urine. One of the 12 S. Paratyphi B isolates was cultured from blood, and no such isolates were cultured from urine (Table C.2, Appendix C).

Antimicrobial Resistance: Results are presented in Table 4 and Table B.4, Appendix B. Resistance to amoxicillin-clavulanic acid was detected in 4% (2/53) of S. Paratyphi A isolates. Ceftiofur and ceftriaxone resistance were each detected in 2% (1/53) of S. Paratyphi A isolates. Reduced susceptibility to ciprofloxacin and resistance to nalidixic acid were each detected in 89% (47/53) of S. Paratyphi A isolates. None of the S. Paratyphi A or S. Paratyphi B isolates were resistant to ciprofloxacin or amikacin. None of the S. Paratyphi B isolates were resistant to amoxicillin-clavulanic acid, ceftiofur, ceftriaxone, cefoxitin, gentamicin, kanamycin, nalidixic acid, or trimethoprim-sulfamethoxazole or had reduced susceptibility to ciprofloxacin.

Antimicrobial Resistance Patterns: Results are presented in Table 8 and Tables C.3 and C.4, Appendix C. Resistance to 1 or more antimicrobials was detected in 91% (48/53) of S. Paratyphi A isolates and in 2 of 12 S. Paratyphi B isolates. Resistance to 5 or more antimicrobials was detected in 4% (2/53) of S. Paratyphi A isolates and in 1 of 12 S. Paratyphi B isolates. The most common resistance pattern among S. Paratyphi A isolates was NAL (87%, 46/53). Of those isolates, 46% (21/46) were from Ontario and 37% (17/46) were from British Columbia (no phage type information available). The pattern involving the greatest number of antimicrobials among S. Paratyphi A isolates was ACKSSuT-A2C-CRO-GEN (no phage type information available) and among S. Paratyphi B isolates was ACSSuT (1 atypical phage type).

Among blood isolates, the most common resistance pattern was NAL (89%, 31/35), and all isolates having this pattern were S. Paratyphi A. The 1 S. Paratyphi A urine isolate was also resistant to nalidixic acid.

Temporal Variations: Results are presented in Figure 3. Between 2008 and 2003 and between 2008 and 2007, there were no significant temporal variations in the percentages of S. Paratyphi A or S. Paratyphi B isolates resistant to the selected antimicrobials.

Salmonella Typhi
(n = 186)

Provincial incidence rates for Salmonella Typhi detection in humans varied from 0 to 2.34 cases (median =  0.22) per 100,000 inhabitant-years. No cases were reported in New Brunswick, Nova Scotia, Prince Edward Island, or Newfoundland and Labrador. The most common phage types recovered were PT E1 (35%, 65/186), PT UVS (I + IV) (11%, 20/186), PT UVS (10%, 19/186), and PT G3 (10%, 18/186). The phage type could not be identified and was designated as atypical in 8% (15/186) of isolates. Seventy-five percent (140/186) of isolates were cultured from blood, and less than 1% (1/186) were cultured from urine (Table C.2, Appendix C).

Antimicrobial Resistance: Results are presented in Table 5 and Table B.5, Appendix B. Reduced susceptibility to ciprofloxacin was detected in 72% (134/186) of S. Typhi isolates. Resistance to nalidixic acid was detected in 69% (129/186). None of the isolates were resistant to amoxicillin-clavulanic acid, ceftiofur, ceftriaxone, ciprofloxacin, amikacin, cefoxitin, or gentamicin.

Antimicrobial Resistance Patterns: Results are presented in Table 8 and Tables C.3 and C.4, Appendix C. Resistance to 1 or more antimicrobials was detected in 74% (137/186) of S. Typhi isolates. Resistance to 5 or more antimicrobials was detected in 17% (31/186). The most common resistance pattern was NAL (54%, 100/186). This resistance pattern was mainly detected among PT E1 (47%, 47/100), PT UVS (I + IV) (14%, 14/100), and PT G3 (10%, 10/100) isolates. Fifty percent (50/100) of the isolates that had the NAL resistance pattern were from Ontario. Three percent (6/186) of isolates had reduced susceptibility to ciprofloxacin but were not resistant to nalidixic acid. The pattern involving the greatest number of antimicrobials was ACSSuT-NAL-SXT (3 untypable, 1 PT E1, and 1 PT UVS [I + IV]). Among blood isolates, the most common resistance pattern was NAL, which was detected in 54% (76/140) of isolates. Common phage types associated with this resistance pattern included PT E1 (45%, 34/76) and PT UVS (I + IV) (13%, 10/76). The 1 urine isolate (PT G3) also had the NAL resistance pattern.

Temporal Variations: Results are presented in Figure 3. The percentage of S. Typhi isolates with resistance to nalidixic acid was significantly higher in 2008 (69%) than in 2003 (44%, 56/127) but was similar between 2008 and 2007 (78%, 122/156). The percentage of S. Typhi isolates with resistance to tetracycline was significantly lower in 2008 (6%, 11/186) than in 2007 (13%, 20/156). Between 2008 and 2003 and between 2008 and 2007, there were no other significant temporal variations in the percentages of isolates resistant to the selected antimicrobials.

Salmonella Typhimurium
(n = 474)

Provincial incidence rates for Salmonella Typhimurium detection in humans varied from 1.17 to 3.49 (median = 2.18) cases per 100,000 inhabitant-years. The most common phage types recovered were PT 108 (21%, 99/474), PT atypical (14%, 68/474), PT 104 (11%, 52/474), and PT 104b (6%, 29/474). Three percent (16/474) of isolates were cultured from blood, and 2% (11/474) were cultured from urine (Table C.2, Appendix C).

Antimicrobial Resistance: Results are presented in Table 6 and Table B.6, Appendix B. Resistance to amoxicillin-clavulanic acid was detected in 2% (12/474) of S. Typhimurium isolates. Resistance to ceftiofur and ceftriaxone were each detected in 2% (11/474). Three percent (15/474) of the isolates had reduced susceptibility to ciprofloxacin. Resistance to nalidixic acid was detected in 2% (10/474) of isolates. None of the isolates were resistant to ciprofloxacin or amikacin.

Antimicrobial Resistance Patterns: Results are presented in Table 8 and Tables C.3 and C.4, Appendix C. Resistance to 1 or more antimicrobials was detected in 40% (187/474) of S. Typhimurium isolates. Resistance to 5 or more antimicrobials was detected in 25% (118/474). The most common resistance pattern was ACSSuT (14%, 64/474), and most isolates with this pattern were PT 104 (55%, 35/64) and PT 104b (28%, 18/64). One isolate designated as an untypable phage type had reduced susceptibility to ciprofloxacin and resistance to ceftriaxone. One percent (5/474) of isolates had reduced susceptibility to ciprofloxacin but were not resistant to nalidixic acid. The patterns involving the greatest number of antimicrobials among isolates were ACSSuT-A2C-CRO-GEN (1 PT U302 and 1 untypable phage type), ACSSuT-A2C-CRO-SXT (1 PT U302), ACSSuT-A2C-CRO (2 PT 99 and 1 PT U302), and ACKSSuT-GEN-NAL-SXT (1 PT 120).

Ten of the 16 blood isolates and 7 of the 11 urine isolates were resistant to 1 or more antimicrobials. The most common resistance pattern among blood isolates was ACSSuT (6/16) and among urine isolates was AMP-SSS-TET (2/11).

Temporal Variations: Results are presented in Figure 3. The percentages of S. Typhimurium isolates with resistance to ampicillin, streptomycin, and tetracycline were significantly lower in 2008 (31% [145/474], 30% [144/474], and 32% [152/474], respectively) than in 2003 (44% [269/605], 39% [234/605)], and 47% [282/605], respectively). However, percentages of isolates with resistance to ampicillin and streptomycin were significantly higher in 2008 (31% and 30%, respectively) than in 2007 (22% [145/658] and 23% [149/658], respectively). The percentage of isolates with resistance to tetracycline remained similar between 2008 (32%) and 2007 (27%, 176/658). Between 2008 and 2003 and between 2008 and 2007, there were no other significant temporal variations in the percentages of isolates resistant to the selected antimicrobials.

Salmonella "Other Serovars"
(n = 1,151)

The Salmonella "Other Serovars" represented 32% (1,151/3,601) of all S almonella isolates and included 162 different serovars. Four percent (49/1,151) of the isolates were cultured from blood, and 7% (78/1,151) were cultured from urine (Table C.2, Appendix C).

Antimicrobial Resistance: Results are presented in Table 7 and Table B.7, Appendix B. Resistance to amoxicillin-clavulanic acid was detected in 2% (19/1,151) of Salmonella "Other Serovars" isolates (Agona, Anatum, ssp. I 4,[5],12:i:-, ssp. I Rough-O:i:-, ssp. I Rough-O:i:1,2, ssp. Rough-O:r:1,2, Kentucky, Reading, Saintpaul, and Stanley). Resistance to ceftiofur and ceftriaxone were each detected in 2% (21/1,151) of isolates (ssp. I 4,[5],12:i:-, Agona, Anatum, Hadar, ssp . I Rough-O:i:1,2, ssp. Rough-O:r:1,2, Irenea, Kentucky, Reading, Saintpaul, and Stanley). One percent (11/1,151) of isolates (Kentucky) were resistant to ciprofloxacin, and 5% (60/1,151) had reduced susceptibility to ciprofloxacin and were mainly ssp. I 4,[5],12:i:-, Infantis, Hadar, Agona, Thompson, and ssp. I 4,[5],12:b:-. Resistance to nalidixic acid was detected in 5% (56/1,151). None of the isolates were resistant to amikacin.

Antimicrobial Resistance Patterns: Results are presented in Table 8 and Tables C.3 and C.4, Appendix C. Resistance to 1 or more antimicrobials was detected in 24% (274/1,151) of Salmonella "Other Serovars" isolates. Most of these isolates included serovars Hadar (22%. 60/274), ssp. I 4,[5],12:i:- (18%, 48/274), Agona (7%, 18/274), and Kentucky (7%, 18/274). Resistance to 5 or more antimicrobials was detected in 5% (60/1,151) of isolates. The most common resistance pattern was STR-TET (5%, 55/1,151), which was detected primarily in Hadar (82%, 45/55) and Kentucky (11%, 6/55) isolates. Less than 1% (2/1,151) of isolates (Saintpaul and ssp. I 4,[5],12:i:-) had reduced susceptibility to ciprofloxacin and resistance to ceftriaxone. Two percent (18/1,151) of the isolates (Corvallis, Derby, ssp. I 4,[5],12:i:-, ssp. I Rough-O:i:-, Litchfield, Manhattan, Mbandaka, Muenster, Saintpaul, and Weltevreden) had reduced susceptibility to ciprofloxacin and were not resistant to nalidixic acid. The pattern involving the greatest number of antimicrobials among isolates was ACKSSuT-A2C-CRO-GEN-SXT (1 Saintpaul).

Twenty-two percent (11/49) of blood isolates and 20% (14/78) of urine isolates were resistant to 1 or more antimicrobials. The most common resistance patterns among blood isolates were NAL (4% 2/49) and STR-TET (4%, 2/49) and among urine isolates were SSS-TET (4%, 3/78) and STR-TET (4%, 3/78).

Temporal Variations: Results are presented in Figure 3. Between 2008 and 2003, no significant temporal variations were detected in the percentages of Salmonella "Other Serovars" isolates with resistance to the selected antimicrobials. The percentage of isolates with resistance to ceftiofur was significantly higher in 2008 (2%) than in 2007 (1%, 8/1,090). Similarly, the percentages of isolates with resistance to gentamicin and nalidixic acid were significantly higher in 2008 (2% [28/1,151] and 5%, respectively) than in 2007 (1% [6/1,090] and 3% [35/1,090)], respectively). Between 2008 and 2007, there were no other significant temporal variations in the percentages of isolates resistant to the selected antimicrobials.

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Beef Cattle

Salmonella

Surveillance of Animal Clinical Isolates^{Footnote 15}
(n = 134)

Note: These isolates may be from either dairy or beef cattle.

Serovars: Results are presented in Table 9 and Table C.3, Appendix C. The most common Salmonella serovars were Typhimurium (22%, 30/134), Typhimurium var. 5- (19%, 25/134), and Kentucky (11%, 15/134). These 3 serovars accounted for 52% (70/134) of the isolates.

Antimicrobial Resistance: Results are presented in Table B.8, Appendix B. Resistance to amoxicillin-clavulanic acid, ceftiofur, and ceftriaxone were each detected in 4% (6/134) of Salmonella isolates. Reduced susceptibility to ciprofloxacin was detected in 1% (1/134) of the isolates. None of the isolates were resistant to ciprofloxacin, amikacin, or nalidixic acid.

Antimicrobial Resistance Patterns: Results are presented in Table 9 and Table C.4, Appendix C. Resistance to 1 or more antimicrobials was detected in 39% (52/134) of Salmonella isolates. Resistance to 5 or more antimicrobials was detected in 28% (38/134) of isolates (21 S. Typhimurium var. 5-, 13 S. Typhimurium, 3 S. Heidelberg, and 1 S. Agona). The most common resistance patterns were ACKSSuT (7%, 10/134), ACKSSuT-GEN (5%, 7/134), and ACSSuT (4%, 6/134). Seven of the 10 isolates with the ACKSSuT resistance pattern were S. Typhimurium var. 5-, and 3 were S. Typhimurium. One percent (1/134) of isolates had reduced susceptibility to ciprofloxacin but were not resistant to nalidixic acid. The resistance pattern involving the greatest number of antimicrobials among isolates was ACKSSuT-A2C-CRO-SXT (3 S. Typhimurium PT 108).

Escherichia coli

Abattoir Surveillance
(n = 176)

Recovery: Escherichia coli isolates were recovered from 97% (176/182) of beef cattle caecal samples (Table C.5, Appendix C).

Antimicrobial Resistance: Results are presented in Figure 4 and Table B.9, Appendix B. None of the E. coli isolates were resistant to amoxicillin-clavulanic acid, ceftiofur, ceftriaxone, ciprofloxacin, amikacin, cefoxitin, gentamicin, nalidixic acid, or trimethoprim-sulfamethoxazole. Additionally, none of the isolates had reduced susceptibility to ciprofloxacin.

Antimicrobial Resistance Patterns: Resistance to 1 or more antimicrobials was detected in 39% (69/176) of E. coli isolates. None of the isolates were resistant to 5 or more antimicrobials. The most common resistance patterns were TET (17%, 30/176) and SSS-TET (5%, 9/176). The patterns including the greatest number of antimicrobials were CHL-STR-SSS-TET and KAN-STR-SSS-TET, which were each detected in 4 isolates, 1 of which had both patterns.

Temporal Variations: Results are presented in Figure 5. Between 2008 and 2003 and between 2008 and 2007, there were no significant temporal variations in percentages of E. coli isolates resistant to the selected antimicrobials.

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Retail Meat Surveillance
(n = 572)
(British Columbia [n = 88], Saskatchewan [n = 134], Ontario [n = 185], Québec [n = 126], Maritimes region [n = 39])

Recovery: Escherichia coli isolates were recovered from 72% (572/798) of retail beef samples. Province/region-specific percentages of beef samples from which isolates were recovered were as follows: British Columbia, 77% (88/115); Saskatchewan, 76% (134/177); Ontario, 78% (185/236); Québec, 59% (126/214); and the Maritimes region, 70% (39/56; Table C.5, Appendix C).

Antimicrobial Resistance: Results are presented in Figure 6 and Table B.10, Appendix B. Resistance to amoxicillin-clavulanic acid, ceftiofur, and ceftriaxone were each detected in 2% (2/88) of E. coli isolates from British Columbia, 1% (1/134) of isolates from Saskatchewan, 1% (2/185) of isolates from Ontario, 1% (1/126) of isolates from Québec, and 3% (1/39) of isolates from the Maritimes region. There were no significant differences among the provinces/region in percentages of isolates with resistance to any antimicrobial tested. None of the isolates from any province/region were resistant to ciprofloxacin, amikacin, or nalidixic acid or had reduced susceptibility to ciprofloxacin.

Antimicrobial Resistance Patterns: Resistance to 1 or more antimicrobials was detected in 28% (25/88) of E. coli isolates from British Columbia, 22% (29/134) of isolates from Saskatchewan, 23% (43/185) of isolates from Ontario, 18% (23/126) of isolates from Québec, and 21% (8/39) of isolates from the Maritimes region. Resistance to 5 or more antimicrobials was detected in 3% (3/88) of isolates from British Columbia, 1% (1/134) of isolates from Saskatchewan, 3% (6/185) of isolates from Ontario, 1% (1/126) of isolates from Québec, and 3% (1/39) of isolates from the Maritimes region. Among the isolates from all 5 provinces/region, the most common resistance patterns were TET (9%, 51/572) and SSS-TET (3%, 15/572). The resistance pattern involving the greatest number of antimicrobials among isolates was AKSSuT-A2C-CRO, which was detected in 1 isolate from Québec.

Temporal Variations: Results are presented in Figure 7. The percentage of E. coli isolates from Saskatchewan with resistance to tetracycline was significantly higher in 2008 (20%, 27/134) than in 2007 (8%, 9/118) and 2005 (9%, 11/120). The percentage of isolates from Ontario with resistance to streptomycin was significantly higher in 2008 (11%, 21/185) than in 2007 (3%, 6/187). For the other provinces/region, there were no significant temporal variations in the percentages of isolates resistant to the selected antimicrobials.

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Campylobacter

Abattoir Surveillance
(n = 128)

Recovery: Campylobacter isolates were recovered from 71% (129/182) of beef cattle caecal samples (Table C.5, Appendix C). One isolate could not be cultured after freezing, leaving 128 isolates for antimicrobial susceptibility testing. Twenty-three percent (30/128) of the remaining isolates were C. coli, 73% (93/128) were C. jejuni, and 4% (5/128) were other Campylobacter spp.

Antimicrobial Resistance: Results are presented in Figure 8 and Table B.11, Appendix B. Resistance to ciprofloxacin was detected in 2% (3/128) of Campylobacter isolates (1 C. coli and 2 C. jejuni ). None of the isolates were resistant to telithromycin, azithromycin, clindamycin, erythromycin, or gentamicin, and none were non-susceptible to florfenicol.

Antimicrobial Resistance Patterns: Results are presented in Table 10. Resistance to 1 or more antimicrobials was detected in 67% (86/128) of Campylobacter isolates. Resistance to 3 antimicrobials was detected in 2% (2/128). The most common resistance pattern was TET (63%, 80/128). The pattern with the greatest number of antimicrobials was CIP-NAL-TET, which was detected in 2 C. jejuni isolates.

Temporal Variations: Results are presented in Figure 9. Between 2008 and 2006 and between 2008 and 2007, there were no significant temporal variations in the percentages of Campylobacter isolates with resistance to the selected antimicrobials.

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Chickens

Salmonella

Abattoir Surveillance
(n = 234)

Recovery: Salmonella isolates were recovered from 27% (234/851) of chicken caecal samples (Table C.5, Appendix C).

Serovars: Results are presented in Table 11 and Table C.2, Appendix C. The most common Salmonella serovars were Kentucky (40%, 93/234), Enteritidis (19%, 45/234), and Heidelberg (14%, 33/234). These 3 serovars accounted for 73% (171/234) of the isolates.

Antimicrobial Resistance: Results are presented in Figure 10 and Table B.12, Appendix B. Resistance to amoxicillin-clavulanic acid, ceftiofur, and ceftriaxone were each detected in 12% (27/234) of Salmonella isolates. None of the isolates were resistant to ciprofloxacin, amikacin, nalidixic acid, or trimethoprim-sulfamethoxazole. Additionally, none had reduced susceptibility to ciprofloxacin.

Antimicrobial Resistance Patterns: Results are presented in Table 11 and Table C.4, Appendix C. Resistance to 1 or more antimicrobials was detected in 52% (121/234) of Salmonella isolates. Resistance to 5 or more antimicrobials was detected in 12% (28/234) of the isolates (17 S. Kentucky, 6 S. Heidelberg, 2 S. Kiambu, 1 S. Infantis, 1 S. Typhimurium, and 1 S. Typhimurium var. 5-). The most common resistance patterns were STR-TET (29%, 69/234) and A2C-AMP-CRO (5%, 12/234). The main serovar associated with the STR-TET pattern was Kentucky (77%, 53/69). The patterns involving the greatest number of antimicrobials among isolates were A2C-AMP-CRO-STR-SSS and A2C-AMP-CRO-STR-TET, which were detected in 1 and 10 S. Kentucky isolates, respectively.

Temporal Variations: Results are presented in Figure 11. The percentage of Salmonella isolates with resistance to tetracycline was significantly higher in 2008 (41%, 96/234) than in 2003 (19%, 24/126). The percentages of isolates with resistance to ceftiofur and ampicillin were significantly lower in 2008 (12% and 16% [38/234], respectively) than in 2004 (22% [31/142] and 28% [39/142], respectively).^{Footnote 16}

Figure 10 - Click to enlarge

Figure 11 - Click to enlarge

Retail Meat Surveillance
(n = 382)
(British Columbia [n = 47], Saskatchewan [n = 64], Ontario [n = 139], Québec [n = 120], Maritimes region [n = 12])

Recovery: Salmonella isolates were recovered from 40% (382/960) of retail chicken samples (Table C.5, Appendix C). Province/region-specific percentages of chicken samples from which isolates were recovered were as follows: British Columbia, 32% (47/145); Saskatchewan, 40% (64/161); Ontario, 45% (139/311); Québec, 42% (120/287); and the Maritimes region, 22% (12/56).

Serovars: Results are presented in Table 12 and Table C.2, Appendix C. The most common Salmonella serovars were Kentucky (31%, 120/382), Heidelberg (20%, 78/382), Enteritidis (16%, 62/382), and Hadar (6%, 22/382). The most common serovars by province/region were Enteritidis (30%, 14/47) and Kentucky (28%, 13/47) for British Columbia; Kentucky (23%, 15/64) and Enteritidis (22%, 14/64) for Saskatchewan; Kentucky (33%, 46/139) and Enteritidis (16%, 22/139) for Ontario; Kentucky (37%, 44/120) and Heidelberg (32%, 38/120) for Québec; and Heidelberg (4/12) and Thompson (3/12) for the Maritimes region.

Antimicrobial Resistance: Results are presented in Figure 12 and Table B.13, Appendix B. Resistance to amoxicillin-clavulanic acid, ceftiofur, and ceftriaxone were each detected in 21% (10/47), 23% (11/47), and 23% (11/47) of Salmonella isolates from British Columbia, respectively, and resistance to each was also detected in 5% (3/64) of isolates from Saskatchewan. Nine percent (13/139) of isolates from Ontario were resistant to amoxicillin-clavulanic acid, and ceftiofur and ceftriaxone resistance were each detected in 10% (14/139). Resistance to amoxicillin-clavulanic acid, ceftiofur, and ceftriaxone were each detected in 15% (18/120) of isolates from Québec, and resistance to each was also detected in 2 of 12 isolates from the Maritimes region. There were no significant differences among the provinces/region in percentages of isolates with resistance to any of the antimicrobials tested. None of the isolates from the 5 provinces/region were resistant to ciprofloxacin, amikacin, or nalidixic acid. Reduced susceptibility to ciprofloxacin was not detected in any isolates.

Antimicrobial Resistance Patterns: Results are presented in Table 12. Resistance to 1 or more antimicrobials was detected in 40% (19/47) of Salmonella isolates from British Columbia, 44% (28/64) of isolates from Saskatchewan, 47% (65/139) of isolates from Ontario, 54% (65/120) of isolates from Québec, and 3 of 12 isolates from the Maritimes region. Resistance to 5 or more antimicrobials was detected in 26% (12/47) of isolates from British Columbia (8 S. Kentucky, 2 S. Heidelberg, 1 S. Typhimurium, and 1 Salmonella ssp. I 4,[5],12:-:-), 6% (4/64) of isolates from Saskatchewan (1 S. Heidelberg, 1 S. Infantis, 1 S. Typhimurium, and 1 Salmonella ssp. I 4,[5],12:-:-), 10% (14/139) of isolates from Ontario (3 S. Heidelberg, 3 S. Kentucky, 3 S. Kiambu, 1 S. Agona, 1 S. Thompson, 1 S. Typhimurium var. 5-, 1 Salmonella ssp. I 8,20:-:z6, and 1 Salmonella ssp. I Rough:r:1,2), 14% (17/120) of isolates from Québec (6 S. Heidelberg, 6 S. Kentucky, 3 S. Kiambu, 1 S. Infantis, and 1 S. Typhimurium var. 5-), and 2 of 12 isolates from the Maritimes region (1 S. Heidelberg and 1 Salmonella ssp. I 4,[5],12:-:- ). Among isolates from all 5 provinces/region, the most common resistance patterns were STR-TET (21%, 81/382), A2C-AMP-CRO (7%, 25/382), and TET (4%, 17/382). The resistance patterns involving the greatest number of antimicrobials among isolates were A2C-AMP-CRO-SSS-TET-SXT and A2C-AMP-CRO-GEN-STR-SSS, which were detected in 1 isolate from Ontario ( S. Kiambu) and 1 from the Maritimes region (Salmonella ssp. I 4,[5],12:-:-), respectively.

Temporal Variations: Results are presented in Figure 13. The percentage of isolates from Saskatchewan with resistance to nalidixic acid was significantly lower in 2008 (0%) than in 2005 (10%, 2/21). The percentages of isolates from Ontario with resistance to ampicillin and ceftiofur were significantly lower in 2008 (14% [19/139] and 10%, respectively) than in 2004^{Footnote 17} (51% [28/55] and 45% [25/55], respectively). The percentages of isolates from Ontario with resistance to streptomycin and tetracycline were significantly higher in 2008 (32% [45/139] and 36% [50/139], respectively) than in 2003 (4% [1/26] and 0% [0/26], respectively). The percentages of isolates from Québec with resistance to ampicillin and ceftiofur were significantly lower in 2008 (21% [25/120] and 15%, respectively) than in 2004 (47% [28/60] and 37% [22/60], respectively). In the other provinces/region, there were no significant temporal variations in the percentages of isolates resistant to the selected antimicrobials.

Figure 12 - Click to enlarge

Figure 13 - Click to enlarge

Surveillance of Animal Clinical Isolates^{Footnote 18}
(n = 209)

Note: These isolates may be from layer hens or broiler chickens, or from their environment.

Serovars: Results are presented in Table 13 and Table C.2, Appendix C. The most common Salmonella serovars were Enteritidis (47%, 99/209), Kentucky (18%, 38/209), and Heidelberg (15%, 31/209). These 3 serovars accounted for 80% (168/209) of the isolates.

Antimicrobial Resistance: Results are presented in Table B.14, Appendix B. Resistance to amoxicillin-clavulanic acid, ceftiofur, and ceftriaxone were each detected in 16% (33/209, 34/209, and 34/209, respectively) of Salmonella isolates. None of the isolates were resistant to ciprofloxacin, amikacin, nalidixic acid, or trimethoprim-sulfamethoxazole, and none had reduced susceptibility to ciprofloxacin.

Antimicrobial Resistance Patterns: Results are presented in Table 13 and Table C.4, Appendix C.

Resistance to 1 or more antimicrobials was detected in 32% (66/209) of Salmonella isolates. Resistance to 5 or more antimicrobials was detected in 17% (35/209) of the isolates (including 19 S. Kentucky and 6 S. Heidelberg). The most common resistance patterns were A2C-AMP-CRO (7%, 15/209), A2C-AMP-CRO-STR-TET (5%, 10/209), and TET (5%, 10/209). Fifteen isolates had the A2C-AMP-CRO resistance pattern, including serovars Kentucky (7/15) and Heidelberg (5/15). Isolates with the A2C-AMP-CRO-STR-TET resistance pattern were all S. Kentucky. The pattern involving the greatest number of antimicrobials was ACKSSuT-A2C-CRO-GEN (1 S. Mbandaka).

Escherichia coli

Abattoir Surveillance
(n = 170)

Recovery: Escherichia coli isolates were recovered from 99% (170/171) of abattoir chicken caecal samples (Table C.5, Appendix C).

Antimicrobial Resistance: Results are presented in Figure 14 and Table B.15, Appendix B. Resistance to amoxicillin-clavulanic acid, ceftiofur, and ceftriaxone were detected in 26% (45/170), 20% (34/170), and 23% (39/170) of the E. coli isolates, respectively. Three percent (5/170) of isolates had reduced susceptibility to ciprofloxacin. Resistance to nalidixic acid was detected in 4% (6/170) of isolates. None of the isolates were resistant to ciprofloxacin or amikacin.

Antimicrobial Resistance Patterns: Resistance to 1 or more antimicrobials was detected in 77% (131/170) of E. coli isolates. Resistance to 5 or more antimicrobials was detected in 31% (52/170). The most common resistance patterns were TET (6%, 11/170) and A2C-AMP-CRO (6%, 11/170), as well as STR-TET (5%, 9/170). Reduced susceptibility to ciprofloxacin and resistance to ceftriaxone were each detected in 1% (1/170) of isolates. The pattern involving the greatest numbers of antimicrobials was ACSSuT-A2C-CRO-GEN-NAL.

Temporal Variations: Results are presented in Figure 15. The percentage of E. coli isolates with resistance to tetracycline was significantly lower in 2008 (51%, 86/170) than in 2003 (69%, 106/153), whereas the percentage with resistance to trimethoprim-sulfamethoxazole was significantly higher in 2008 (12%, 20/170) than in 2007 (4%, 8/180). There were no other significant temporal variations in the percentages of isolates resistant to the selected antimicrobials.

Figure 14 - Click to enlarge

Figure 15 - Click to enlarge

Retail Meat Surveillance
(n = 479)
(British Columbia [n = 70], Saskatchewan [n = 91], Ontario [n = 150], Québec [n = 131], Maritimes region [n = 37])

Recovery: Escherichia coli isolates were recovered from 91% (480/526) of retail chicken samples (Table C.5, Appendix C). Province/region-specific percentages of chicken samples from which isolates were recovered were as follows: British Columbia, 90% (70/78); Saskatchewan, 99% (91/92); Ontario, 96% (150/156); Québec, 91% (131/144); and the Maritimes region, 68% (38/56). Among isolates recovered, 1 from the Maritimes region could not be re-cultured for antimicrobial susceptibility testing, resulting in a total of 37 isolates for that region.

Antimicrobial Resistance: Results are presented in Figure 16 and Table B.16, Appendix B. Resistance to amoxicillin-clavulanic acid was detected in 53% (37/70) of E. coli isolates from British Columbia, 21% (19/91) of isolates from Saskatchewan, 27% (41/150) of isolates from Ontario, 22% (29/131) of isolates from Québec, and 27% (10/37) of isolates from the Maritimes region. Resistance to ceftiofur was detected in 49% (34/70) of isolates from British Columbia, 20% (18/91) of isolates from Saskatchewan, 24% (36/150) of isolates from Ontario, 18% (24/131) of isolates from Québec, and 19% (7/37) of isolates from the Maritimes region. Resistance to ceftriaxone was detected in 54% (38/70) of isolates from British Columbia, 21% (19/91) of isolates from Saskatchewan, 28% (42/150) of isolates from Ontario, 21% (28/131) of isolates from Québec, and 27% (10/37) of isolates from the Maritimes region. Resistance to ciprofloxacin was detected in 1% (1/131) of isolates from Québec. Reduced susceptibility to ciprofloxacin was detected in 4% (3/70) of isolates from British Columbia, 7% (6/91) of isolates from Saskatchewan, 4% (6/150) of isolates from Ontario, and 8% (11/131) of isolates from Québec. Resistance to nalidixic acid was detected in 4% (3/70) of isolates from British Columbia, 7% (6/91) of isolates from Saskatchewan, 4% (6/150) of isolates from Ontario, and 8% (11/131) of isolates from Québec.

The percentages of isolates with resistance to amoxicillin-clavulanic acid and ceftriaxone were significantly higher for British Columbia than for Saskatchewan, Ontario, and Québec. The percentages of isolates from British Columbia with resistance to ceftiofur and cefoxitin were significantly higher than values for the 4 other provinces/region. The percentage of isolates from British Columbia with resistance to ampicillin was also significantly higher than values for the 4 other provinces/region. On the other hand, the percentage of isolates from Québec with resistance to gentamicin was significantly higher than that for British Columbia. The percentages of isolates from Québec with resistance to trimethoprim-sulfamethoxazole and sulfisoxazole were significantly higher than respective values for Saskatchewan. There were no significant differences among provinces/region in percentages of isolates resistant to any other antimicrobial tested. None of the isolates from any province/region were resistant to amikacin, and no isolates from the Maritimes region had reduced susceptibility to ciprofloxacin.

Antimicrobial Resistance Patterns: Resistance to 1 or more antimicrobials was detected in 77% (54/70) of E. coli isolates from British Columbia, 70% (64/91) of isolates from Saskatchewan, 69% (103/150) of isolates from Ontario, 70% (92/131) of isolates from Québec, and 62% (23/37) of isolates from the Maritimes region. Resistance to 5 or more antimicrobials was detected in 51% (36/70) of isolates from British Columbia, 22% (20/91) of isolates from Saskatchewan, 30% (45/150) of isolates from Ontario, 27% (36/131) of isolates from Québec, and 27% (10/37) of isolates from the Maritimes region. Among the isolates from all 5 provinces/region, the most common resistance patterns were A2C-AMP-CRO (10%, 46/479), TET (6%, 28/479), GEN-STR-SSS (3%, 14/479), and A2C-AMP-CRO-TET (3%, 14/479). Resistance to ceftriaxone and reduced susceptibility to ciprofloxacin were both detected in 2% (11/480) of isolates, which were received from all locations except Saskatchewan and the Maritimes region. The resistance pattern involving the greatest number of antimicrobials was ACKSSuT-A2C-CRO-GEN-NAL (1 isolate from British Columbia).

Temporal Variations: Results are presented in Figure 17. The percentages of E. coli isolates from Saskatchewan with resistance to ampicillin and ceftiofur were significantly higher in 2008 (40% [37/91] and 20%, respectively) than in 2005 (24% [20/82] and 4% [3/82]). The percentage of isolates from Saskatchewan with resistance to ceftiofur was significantly higher in 2008 (20%) than in both 2007 (13%, 10/75) and 2005 (4%, 3/82). The percentages of isolates from Québec with resistance to ampicillin and ceftiofur were significantly lower in 2008 (33% [43/131] and 18%, respectively) than in 2004 (52% [82/158] and 34% [54/158], respectively). The percentage of isolates from Québec with resistance to nalidixic acid was significantly higher in 2008 (8%) than in 2003 (0%, 0/111). The percentage of isolates from Québec with resistance to ceftiofur was significantly higher in 2008 (18%) than in 2006 (6%, 8/135). In the other provinces/region, there were no significant temporal variations in the percentages of isolates resistant to selected antimicrobials.

Figure 16 - Click to enlarge

Figure 17 - Click to enlarge

Campylobacter

Retail Meat Surveillance
(n = 264)
(British Columbia [n = 50], Saskatchewan [n = 40], Ontario [n = 120], Québec [n = 54])^{Footnote 19}

Recovery: Campylobacter isolates were recovered from 29% (266/904) of retail chicken samples (Table C.5, Appendix C). Eighty-nine percent (235/265) of the isolates were C. jejuni, and 11% (30/265) were C. coli. Province-specific percentages of chicken samples from which isolates were recovered were as follows: British Columbia, 34% (50/145); Saskatchewan, 25% (41/161); Ontario, 39% (121/311); and Québec, 19% (54/287). Among those isolates recovered, 1 isolate from Saskatchewan and 1 from Ontario could not be re-cultured, leaving 40 isolates from Saskatchewan and 120 from Ontario available for antimicrobial susceptibility testing.

Antimicrobial Resistance: Results are presented in Figure 18, Figure 19, and Table B.17, Appendix B. Resistance to ciprofloxacin was detected in 8% (4/50) of Campylobacter isolates from British Columbia, 10% (4/40) of isolates from Saskatchewan, and 4% (5/120) of isolates from Ontario. The distribution of these ciprofloxacin-resistant isolates according to species of Campylobacter was as follows: C. jejuni, 5% (11/235); and C. coli, 7% (2/30). Resistance to telithromycin was detected in 4% (5/120) of isolates from Ontario and 2% (1/54) of isolates from Québec. The distribution of these telithromycin-resistant isolates according to species of Campylobacter was as follows: C. jejuni, 2% (4/234); and C. coli, 7% (2/30). There were no significant differences among the provinces in percentages of resistant isolates for any of the antimicrobials tested. None of the isolates were non-susceptible to florfenicol. None of the isolates from Québec were resistant to ciprofloxacin. Additionally, none of the isolates from British Columbia and Saskatchewan were resistant to telithromycin, azithromycin, clindamycin, erythromycin, or gentamicin.

Antimicrobial Resistance Patterns: Results are presented in Table 14. Resistance to 1 or more antimicrobials was detected in 36% (18/50) of Campylobacter isolates from British Columbia, 45% (18/40) of isolates from Saskatchewan, 53% (63/120) of isolates from Ontario, and 56% (30/54) of isolates from Québec. Resistance to 3 or more antimicrobials was detected in 4% (2/50) of isolates from British Columbia, 10% (4/40) of isolates from Saskatchewan, 10% (12/120) of isolates from Ontario, and 11% (6/54) of isolates from Québec. Among the isolates from all 4 provinces, the most common resistance patterns were TET (38%, 101/264), AZM-ERY-TET (3%, 9/264), and CIP-NAL-TET (3%, 9/264). The resistance pattern involving the greatest number of antimicrobials among the isolates was AZM-CIP-CLI-ERY-NAL-TEL-TET (1 C. jejuni isolate from Ontario).

Temporal Variations: Results are presented in Figure 20. The percentage of Campylobacter isolates from Ontario with resistance to azithromycin was significantly higher in 2008 (8%, 10/120) than in 2007 (2%, 2/117). For the other provinces, there were no significant temporal variations in the percentages of isolates resistant to the selected antimicrobials.

Figure 18 - Click to enlarge

Figure 19 - Click to enlarge

Figure 20 - Click to enlarge

Enterococcus

Retail Meat Surveillance
(n = 464)
(British Columbia [n = 77], Saskatchewan [n = 91], Ontario [n = 154], Québec [n = 142])^{Footnote 20}

Recovery: Enterococcus isolates were recovered from 99.6% (468/470) of retail chicken samples (Table C.5, Appendix C). Four isolates could not be cultured after freezing, leaving 464 isolates available for antimicrobial susceptibility testing. Ninety-four percent (436/464) of the remaining isolates were E. faecalis, 3% (16/464) were other Enterococcus spp., and 3% (12/464) were E. faecium. Province-specific percentages of chicken samples from which Enterococcus was recovered were as follows: British Columbia, 100% (78/78); Saskatchewan, 100% (92/92); Ontario, 99% (154/156); and Québec, 100% (144/144).

Antimicrobial Resistance: Results are presented in Figure 21, Figure 22, and Table B.18, Appendix B. Resistance to ciprofloxacin was detected in 1% (1/91) of Enterococcus isolates from Saskatchewan, 3% (4/154) of isolates from Ontario, and 1% (1/142) of isolates from Québec. Three of the 12 E. faecium isolates and 1% (3/436) of E. faecalis isolates were resistant to ciprofloxacin. Resistance to tigecycline was detected in 1% (1/142) of E. faecalis isolates from Québec. There were no significant differences among provinces in percentages of isolates that were resistant to any antimicrobials. Resistance to ciprofloxacin was not detected in isolates from British Columbia. None of the isolates from any province were resistant to linezolid or vancomycin or were non-susceptible to daptomycin.

Antimicrobial Resistance Patterns: Results are presented in Table 15. Resistance to 1 or more antimicrobials was detected in 96% (74/77) of Enterococcus isolates from British Columbia, 88% (85/91) of isolates from Saskatchewan, 92% (142/154) of isolates from Ontario, and 89% (127/142) of isolates from Québec. Resistance to 5 or more antimicrobials was detected in 18% (14/77) of isolates from British Columbia, 22% (20/91) of isolates from Saskatchewan, 16% (25/154) of isolates from Ontario, and 25% (36/142) of isolates from Québec. Among the isolates from all 4 provinces, the most common resistance patterns were TET (27%, 127/464), ERY-TET-TYL (19%, 89/464), and ERY-STR-TET-TYL (11%, 50/464). The resistance pattern involving the greatest number of antimicrobials among isolates was ERY-LIN-NIT-PEN-STR-QDA-TET-TYL (1 E. faecium isolate from Saskatchewan).

Temporal Variations: Results are presented in Figure 23. The percentages of Enterococcus isolates from Saskatchewan with resistance to erythromycin, streptomycin, and tylosin were significantly higher in 2008 (67% [61/91], 40% [36/91], and 67% [61/91], respectively) than in 2005 (39% [31/80], 20% [16/80], and 40% [32/80], respectively). The percentages of isolates from Saskatchewan with resistance to erythromycin and tylosin were significantly higher in 2008 (67% each) than in 2007 (46% [35/76] each). The percentage of isolates from Ontario with resistance to tylosin was significantly higher in 2008 (51%, 78/154) than in 2007 (39%, 63/161). For the other provinces, there were no significant temporal variations in the percentages of isolates resistant to the selected antimicrobials.

Figure 21 - Click to enlarge

Figure 22 - Click to enlarge