Epidemiology of a Salmonella enterica subsp. enterica serovar typhimurium strain associated with a songbird outbreak

Sonia M. Hernandez, Kevin Keel, Susan Sanchez, Eija Trees, Peter Gerner-Smidt, Jennifer K. Adams, Ying Cheng, Al Ray, Gordon Martin, Andrea Presotto, Mark G. Ruder, Justin Brown, David S. Blehert, Walter Cottrell, John J. Maurer

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54 Scopus citations


Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast.

Original languageEnglish (US)
Pages (from-to)7290-7298
Number of pages9
JournalApplied and environmental microbiology
Issue number20
StatePublished - Oct 2012

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Food Science
  • Ecology
  • Applied Microbiology and Biotechnology


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