Emergence of multidrug-resistant Salmonella enterica serotype 4,[5],12:i:- Involving human cases in Canada: Results from the Canadian Integrated Program on Antimicrobial Resistance Surveillance (CIPARS), 2003-10

Michael R. Mulvey, Rita Finley, Vanessa Allen, Lei Ang, Sadjia Bekal, Sameh El Bailey, David Haldane, Linda Hoang, Greg Horsman, Marie Louie, Lourens Robberts, John Wylie, Elissa McCracken, Stacie Langner, Rafiq Ahmed, Helen Tabor, Matthew Gilmour

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30 Citations (Scopus)


Objectives: Over the last decade, a marked increase in Salmonella enterica serotype 4,[5],12:i:- with a core resistance to ampicillin, streptomycin, sulphonamides and tetracycline (ASSuT) has been observed in Europe. This study describes the emergence and characterization of isolates of multidrug-resistant Salmonella 4,[5],12:i:- in Canada. Methods: Human clinical isolates of Salmonella 4,[5],12:i:- were identified by provincial laboratories from 2003 to 2010. Serotyping and phage typing were performed by standardized methodologies. MIC values were determined using broth microdilution. PCR was used to determine the presence of resistance genes. Multilocus sequence typing was performed on a selected number of isolates. Results: A total of 26251 Salmonella were submitted as part of the Canadian Integrated Program on Antibiotic Resistance Surveillance (CIPARS). Of these, Salmonella 4,[5],12:i:- accounted for a total of 766 isolates (2.9%), and the number increased significantly from 42 (1.4%) in 2003 to 164 (4.8%) in 2010. The ASSuT+ phenotype was observed in 11.9% (n1/491) of Salmonella 4,[5],12:i:- isolates and increased from two isolates in 2003 to 35 isolates in 2010. Two sequence types (STs) were observed. ST34 was mainly associated with the ASSuT isolates (n1/424; 38%), which contained blaTEM, strA-strB, tet(B) and sul2. ST19 was more likely to be associated with the ACSSuT phenotype and contained blaTEM, floR, strA-strB, sul2 and tet(A) or blaPSE-1, floR, aadA2, sul1 and tet(G). Conclusions: The prevalence of Salmonella 4,[5],12:i:- has significantly increased from 2003 to 2010 and it is now the fifth most common serotype reported in Canada causing human disease. Similar antimicrobial resistance patterns, phage types and STs have been observed in Europe.

Original languageEnglish
Article numberdkt149
Pages (from-to)1982-1986
Number of pages5
JournalJournal of Antimicrobial Chemotherapy
Issue number9
Early online date24 May 2013
Publication statusPublished - Sep 2013


  • MDR
  • Resistance
  • Salmonella enterica

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