OBJECTIVES: Resistance to extended-spectrum cephalosporins has increased in Salmonella worldwide, and is a concern in both hospital and community settings. The aim of this report was to investigate cefoxitin-resistant Salmonella isolates identified from human clinical cases across Canada. METHODS: Cefoxitin-resistant isolates, defined as having an MIC > or = 32 mg/L, were screened for the ampC classes DHA, FOX, ENT and CIT in a multiplex PCR followed by sequence analysis. Plasmid analysis by restriction fragment length polymorphism (RFLP) and replicon typing was performed on a convenience sample of cefoxitin-resistant Salmonella. RESULTS: In 2005, 5.3% (181/3442) and in 2006, 3.1% (102/3250) of Salmonella isolates collected from all provinces across Canada displayed cefoxitin resistance. Seventy-one out of 283 (25.1%) were multidrug resistant (MDR), as defined by resistance to at least three different antibiotic classes. The bla(CMY-2) gene was harboured by 96.8% (274/283) of the cefoxitin-resistant isolates. Analysis of CMY-2 plasmids revealed that 19.7% contained genes conferring resistance to multiple antimicrobials. Replicon typing of transformant CMY-2 plasmid DNA revealed the predominance of I1-Igamma and A/C. Of the MDR CMY-2 plasmids, 75% contained replicon type A/C. RFLP patterns of CMY-2 plasmids revealed clusters corresponding to the I1-Igamma and A/C replicon types. CONCLUSIONS: Incompatibility group I1-Igamma is the most prevalent of the Salmonella CMY-2 plasmids, while A/C is associated with MDR CMY-2 plasmids.
OBJECTIVES: Resistance to extended-spectrum cephalosporins has increased in Salmonella worldwide, and is a concern in both hospital and community settings. The aim of this report was to investigate cefoxitin-resistant Salmonella isolates identified from human clinical cases across Canada. METHODS:Cefoxitin-resistant isolates, defined as having an MIC > or = 32 mg/L, were screened for the ampC classes DHA, FOX, ENT and CIT in a multiplex PCR followed by sequence analysis. Plasmid analysis by restriction fragment length polymorphism (RFLP) and replicon typing was performed on a convenience sample of cefoxitin-resistant Salmonella. RESULTS: In 2005, 5.3% (181/3442) and in 2006, 3.1% (102/3250) of Salmonella isolates collected from all provinces across Canada displayed cefoxitin resistance. Seventy-one out of 283 (25.1%) were multidrug resistant (MDR), as defined by resistance to at least three different antibiotic classes. The bla(CMY-2) gene was harboured by 96.8% (274/283) of the cefoxitin-resistant isolates. Analysis of CMY-2 plasmids revealed that 19.7% contained genes conferring resistance to multiple antimicrobials. Replicon typing of transformant CMY-2 plasmid DNA revealed the predominance of I1-Igamma and A/C. Of the MDR CMY-2 plasmids, 75% contained replicon type A/C. RFLP patterns of CMY-2 plasmids revealed clusters corresponding to the I1-Igamma and A/C replicon types. CONCLUSIONS: Incompatibility group I1-Igamma is the most prevalent of the Salmonella CMY-2 plasmids, while A/C is associated with MDR CMY-2 plasmids.
Authors: Marcus Ho Yin Wong; Meiying Yan; Edward Wai Chi Chan; Kan Biao; Sheng Chen Journal: Antimicrob Agents Chemother Date: 2014-04-21 Impact factor: 5.191
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Authors: Saskia Neuert; Satheesh Nair; Martin R Day; Michel Doumith; Philip M Ashton; Kate C Mellor; Claire Jenkins; Katie L Hopkins; Neil Woodford; Elizabeth de Pinna; Gauri Godbole; Timothy J Dallman Journal: Front Microbiol Date: 2018-03-27 Impact factor: 5.640