Salmonella enterica serotype I 4,,12:i:-or “monophasic Salmonella” was rarely detected prior to the mid 1990’s. This serotype has been increasingly isolated from swine in North America and Europe and has been associated with a number of human disease outbreaks that were associated with contaminated pork products. Although increased isolation of Salmonella I 4,,12:i:-from swine samples has been documented, the pathogenic potential of this serovar in pigs had not been reported. Little work has been done to confirm that this organism is truly a cause of digestive system disease in swine. These researchers at Iowa State wanted to better describe the disease causing ability of Salmonella enterica serotype I 4,,12:i:-.
The researchers were able to demonstrate a strong positive association between histologic (microscopic) lesions consistent with enteric salmonellosis and isolation of Salmonella I 4,,12:i:-. In most cases from which Salmonella I 4,,12:i:-or Salmonella Typhimurium were isolated, the severity of histologic lesions was similar. However, the percentage of cases in which histologic lesions consistent with enteric salmonellosis were present was lower for cases from which Salmonella I 4,,12:i:-(72%) was isolated than for cases from which Salmonella Typhimurium (94%) was isolated.
Take Home Message
- Salmonella I 4,,12:i:-, based on this research, is a likely cause of enteric salmonellosis that is very similar in disease causing ability in swine to Salmonella Typhimurium.
- Salmonella I 4,,12:i:- has become the predominant disease causing Salmonella species in swine on a global basis
- Expect to see further research into the characteristics of this organisms that have allowed it to become predominant over other more established Salmonella.
Submitted by Ed Metzger, DVM
Ref: Arruda BL, Burrough ER, Schwartz KJ.Salmonella enterica I 4,,12:i:-Associated with Lesions Typical of Swine Enteric Salmonellosis.Emerg Infect Dis. 2019 Jul;25(7):1377-1379. doi: 10.3201/eid2507.181453.