Background: Salmonella enterica subsp. enterica serovar I 4,5,12:i:- is a variant of Salmonella Typhimurium. S. I 4,[5],12:i:- is a monophasic serovar that lacks the second flagellar antigen (i.e., antigen 1,2 in serovar Typhimurium). This serovar emerged as a common serovar after 1990’s. Multiple reports and outbreaks linked to S. 4,5,12:i:- have occurred globally. Multidrug resistant (MDR) and pan-susceptible strains have been reported. MDR strains with the resistant patterns ACKGSuTm and ACSuGSTTm were reported in Thailand and Spain, respectively (abbrev: ampicillin (A), chloramphenicol (C), kanamycin (K), gentamicin (G) sulfamethoxazole (Su), trimethoprim (Tm), tetracycline (T), streptomycin (S)). Two clones with different gene deletions were identified, one in the US and one in Europe.
Animal reservoir: Chicken and swine are the major animal reservoirs of this serovar.
Geographical distribution: Global distribution, this serovar have been reported among the most common serovars in US, EU, and Thailand.
Outbreaks: Several outbreaks have been associated with serovar I 4,[5],12:i:-.
Year | Location | Associated source | Number of cases |
| 2023 | Canada-multistate | Raw pet food, cattle exposure | 40 |
| 2018 | US-multistate | Kosher Chicken Products | 25 |
2010 | US-multistate | Alfalfa Sprouts | 140 |
2011-2012 | US-multistate | probably live-animal markets | >14 |
2010 | US-multistate | Frozen rodents | 34 |
2010 | France | Dried pork sausage | 69 |
2007 | US-multistate | Pot pie | 272 |
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