McCracken Melissa, Walkty Andrew, Adam Heather J, Baxter Melanie, Blondeau Joseph, Lagacé-Wiens Philippe, Karlowsky James A, Golding George R, Zhanel George G
National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, Manitoba, Canada R3E 3M4.
Department of Medical Microbiology/Infectious Diseases, Max Rady College of Medicine, University of Manitoba, Room 543-745 Bannatyne Avenue, Winnipeg, Manitoba, Canada R3E 0J9.
J Antimicrob Chemother. 2025 Aug 28;80(Supplement_2):ii62-ii71. doi: 10.1093/jac/dkaf222.
Antimicrobial resistance in Pseudomonas aeruginosa is of increasing concern in Canada, leading to limited treatment options and poor clinical outcomes. Herein we characterized carbapenem-resistant P. aeruginosa identified through the Canadian national surveillance program CANWARD.
Antimicrobial susceptibility for 1725 P. aeruginosa isolates was assessed using broth microdilution and 2024 CLSI breakpoints. WGS of carbapenem-resistant isolates was used to identify STs, resistance and virulence markers. Genetic relatedness was further assessed using cgMLST for select STs.
From 2018 to 2023, CANWARD collected 1725 P. aeruginosa isolates, of which 371 (21.5%) were carbapenem-resistant. The majority of carbapenem-resistant P. aeruginosa were isolated from respiratory specimens of male patients aged 18-65 years living in central Canada. Only 0.8% (n = 3) of the carbapenem-resistant isolates harboured a carbapenemase gene. WGS identified mutations associated with OprD dysfunction, MexAB-OprM efflux and AmpC overexpression in 73.6%, 1.1% and 4.9% of isolates, respectively. Most isolates (98.1%) harboured at least one of the following class D β-lactamase genes: OXA-2, OXA-5, OXA-10 or OXA-50-like subfamily. Wide genetic diversity was observed with 151 different STs identified. The most common STs were ST17 (4.6%), ST27 (4.6%) and high-risk clones ST235 (4.3%), ST244 (3.5%), ST253 (6.4%) and ST357 (2.7%). cgMLST clusters were identified amongst 34.9% of the high-risk clones, suggesting clonal dissemination.
Currently, >20% of clinical isolates of P. aeruginosa in Canada are carbapenem-resistant. Genetic evidence indicates that clonal dissemination of high-risk clones is occurring in Canada. High-risk clones are virulent and often MDR. Continued surveillance of P. aeruginosa is important.
在加拿大，铜绿假单胞菌的耐药性问题日益受到关注，这导致治疗选择受限且临床预后不佳。在此，我们对通过加拿大国家监测项目CANWARD鉴定出的耐碳青霉烯铜绿假单胞菌进行了特征分析。
使用肉汤微量稀释法和2024年CLSI标准对1725株铜绿假单胞菌分离株进行药敏试验。对耐碳青霉烯分离株进行全基因组测序，以鉴定序列类型（STs）、耐药和毒力标记。使用核心多位点序列分型（cgMLST）对选定的STs进一步评估遗传相关性。
2018年至2023年，CANWARD收集了1725株铜绿假单胞菌分离株，其中371株（21.5%）耐碳青霉烯。大多数耐碳青霉烯铜绿假单胞菌分离自加拿大中部18 - 65岁男性患者的呼吸道标本。耐碳青霉烯分离株中只有0.8%（n = 3）携带碳青霉烯酶基因。全基因组测序分别在73.6%、1.1%和4.9%的分离株中鉴定出与外膜孔蛋白D（OprD）功能障碍、MexAB - OprM外排和AmpC过表达相关的突变。大多数分离株（98.1%）携带以下至少一种D类β - 内酰胺酶基因：OXA - 2、OXA - 5、OXA - 10或OXA - 50样亚家族。观察到广泛的遗传多样性，共鉴定出151种不同的STs。最常见的STs是ST17（4.6%）、ST27（4.6%）以及高风险克隆ST235（4.3%）、ST244（3.5%）、ST253（6.4%）和ST357（2.7%）。在34.9%的高风险克隆中鉴定出cgMLST聚类，表明存在克隆传播。
目前，加拿大超过20%的铜绿假单胞菌临床分离株耐碳青霉烯。遗传学证据表明加拿大正在发生高风险克隆的克隆传播。高风险克隆具有毒性且通常为多重耐药。持续监测铜绿假单胞菌很重要。
