BACKGROUND: Organisms expressing Klebsiella pneumoniae carbapenemase (KPC) are found in several regions worldwide but are rarely detected in Canada. The first outbreak of KPC-expressing strains of Enterobacteriaceae clinical isolates in a university-affiliated hospital intensive care unit (ICU) in Canada is described.METHODS: Enterobacteriaceae isolates that were flagged by the Vitek 2 (bioMérieux, France) system as possible carbapenemase producers were subjected to the modified Hodge test. Modified Hodge test-positive organisms were analyzed by pulsed-field gel electrophoresis, tested for KPC and other beta-lactamase genes by polymerase chain reaction analysis and underwent subsequent nucleic acid sequencing. Antimicrobial susceptibility profiles were determined by Vitek 2 and Etest (bioMérieux, France). A chart review was conducted to establish epidemiological links.RESULTS: During the study period, 10 unique Enterobacteriaceae isolates expressing KPC were detected from nine ICU patients. Five patients had infections (three pneumonias, one surgical site infection, one urinary tract infection). Isolates included Escherichia coli (5), Klebsiella oxytoca (2), Serratia marcescens (2) and Citrobacter freundii (1). Polymerase chain reaction analysis and sequencing confirmed the presence of KPC-3 in all isolates; four also carried TEM, two CTX-M and one CMY-2. The imipenem minimum inhibitory concentrations as determined by Etest ranged from 0.75 μg/mL to ≥32 μg/mL. Pulsed field gel electrophoresis clonal patterns and patient location in the ICU revealed presumptive horizontal transmission events.CONCLUSIONS: In the present study, Enterobacteriaceae isolates with KPC are emerging and can result in serious infections. The KPC gene can spread via plasmids to different genera of the Enterobacteriaceae family. The dissemination of KPC in Enterobacteriaceae and the consequences for treatment and infection control measures warrant a high degree of vigilance among clinicians and microbiologists.

中文翻译：

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加拿大首次爆发表达肠杆菌科的肺炎克雷伯菌碳青霉烯酶 3 型。

背景：表达肺炎克雷伯菌的生物体碳青霉烯酶 (KPC) 在全球多个地区均有发现，但在加拿大很少检测到。描述了加拿大一所大学附属医院重症监护病房 (ICU) 中表达 KPC 的肠杆菌科临床分离株的首次暴发。进行了改良的 Hodge 测试。通过脉冲场凝胶电泳分析改良的 Hodge 测试阳性生物，通过聚合酶链反应分析测试 KPC 和其他 β-内酰胺酶基因，并进行随后的核酸测序。通过 Vitek 2 和 Etest (bioMérieux, France) 确定抗微生物药物敏感性曲线。进行图表审查以建立流行病学联系。 结果：在研究期间，从 9 名 ICU 患者中检测到 10 种独特的表达 KPC 的肠杆菌科细菌。5 名患者感染（3 例肺炎，1 例手术部位感染，1 例尿路感染）。包括隔离大肠杆菌(5)、催产克雷伯菌(2)、粘质沙雷氏菌(2) 和弗氏柠檬酸杆菌(1). 聚合酶链反应分析和测序证实了所有分离株中都存在 KPC-3；四架还携带了 TEM、两架 CTX-M 和一架 CMY-2。Etest 测定的亚胺培南最小抑制浓度范围为 0.75 μg/mL 至≥32 μg/mL。ICU 中的脉冲场凝胶电泳克隆模式和患者位置揭示了推定的水平传播事件。结论：在本研究中，出现 KPC 肠杆菌科分离株并可能导致严重感染。KPC 基因可以通过质粒传播到肠杆菌科的不同属。KPC 在肠杆菌科中的传播以及治疗和感染控制措施的后果需要临床医生和微生物学家高度警惕。