Characterization of Cefoxitin-Resistant Escherichia coli Isolates from Recreational Beaches and Private Drinking Water in Canada between 2004 and 2006

Abstract

A total of 142 cefoxitin-resistant Escherichia coli isolates from water sources were collected across Canada. Multidrug resistance was observed in 65/142 (45.8%) isolates. The bla CMY-2 gene was identified in 110/142 (77.5%) isolates. Sequencing of the chromosomal ampC promoter region showed mutations from the wild type, previously shown to hyperproduce AmpC. CMY-2-producing plasmids predominantly belonged to replicon groups I1-I␥, A/C, and K/B. The majority of the E. coli isolates belonged to the nonvirulent phylogenetic groups A and B1.

Characterization of bla CMY-2 Plasmids in Salmonella and Escherichia coli Isolates from Food Animals in Canada

“…As observed by others (4,13,14), resistance to agents other than ␤-lactams was observed in repA/C plasmids only, with one exception (Fig. 1).…”

“…These clusters correspond to common groups of bla CMY-2 plasmids previously described in North America (4,12,13,16,20) and contain plasmids from S. enterica and E. coli, with four restriction profiles found in both species (Fig. 1).…”

“…Plasmids from the three remaining clusters (repK, repFIB, and unidentified replicon type) were found in E. coli only. Other Canadian studies have identified E. coli isolates from water that contain plasmids from all five clusters (12,13) and isolates from hospitalized patients that contain plasmids from clusters A, B, C, and E (2). Thus, bla CMY-2 plasmids from these five clusters have disseminated in E. coli from a variety of sources.…”

Genotypic-Phenotypic Discrepancies between Antibiotic Resistance Characteristics of Escherichia coli Isolates from Calves in Management Settings with High and Low Antibiotic Use

“…We found that these isolates had mutations in the promoter and attenuator sequences of the E. coli chromosomal ampC gene that have also been reported from human clinical E. coli isolates in South Africa (39), Spain (7,40), France (12,13,35), Belgium (6), Norway (22), and Denmark (26). They have also been described in animal source E. coli isolates, including those from cattle in Canada (38) and the United Kingdom (34) and pigs in Spain (19) and in E. coli collected from recreational water samples in T A T G T E160 SSuT C A T G T E1026 ASSuTGK T A T G T E1030 ACSSuTKSxtNalRcazAmc T A T G T E1039 ASSuTGKNalRcazAmc T A T G T E1067 ASSuTKCazAmc T A T G T E2534 SSuTGKSxtAmik Canada (37). The locations of base changes were variable, but they had the effect of creating a functional promoter and sometimes affecting the attenuator region as well (6,7,13,35).…”

Characterization of Resistance Genes and Plasmids from Outbreaks and Illness Clusters Caused by Salmonella Resistant to Ceftriaxone in the United States, 2011–2012

“…This was the first time we have observed a bla CMY -IncK/B plasmid among U.S. Salmonella , making it impossible for us to predict a source. However, bla CMY -IncK/B plasmids have been observed among E. coli in Canada from both clinical and environmental sources (beaches and drinking water), suggesting that it may not be linked to a specific source (21, 22). …”