What is the life cycle of salmonella enteritidis like in the internal organs?

The Incidence of Salmonella enteritidis infection is common in hospitals for children and the elderly, and amongst immuno-suppressed individuals.

Salmonella enteritidis can be transmitted to humans through the food production chain. In China and other countries, for example, the consumption of poultry products is a high risk factor and Salmonella enteritidis infection in poultry industry has been rising dramatically in recent years. This increased prevalence of Salmonella enteritidis makes knowing more about its complex life cycle and identifying the regular distribution pattern of Salmonella enteritidis in the internal organs very important.

To learn more about the infection pattern, Dr. Cheng and his colleagues at the Sichuan Agricultural University China used a serovar specific real time PCR for the detection and quantification of Salmonella enteritidis in the internal organs of mice.

Based on their results, the copy number of Salmonella enteritidis DNA in each tissue reached a peak at 24 ¨C 36 h PI, with the liver and spleen containing high concentrations of Salmonella enteritidis, whereas the blood, heart, kidney, pancreas, and gallbladder showed low concentrations. Salmonella enteritidis populations began to decrease and were not detectable at 3 d PI, but were still present up to 12 d PI in the gallbladder, after two weeks for the liver, and after three weeks for the spleen without causing apparent symptoms.

Interestingly, the gallbladder is a site of carriage in this study, it is also the storage site for bile. This study may be the first time it has been reported that Salmonella enteritidis can persist for as long as 12 d PI in the gallbladder of mice. The gallbladder appeared to show gross lesion (such as swelling) at 20 h to 2 d PI. Importantly, there were no significant gross lesions over the 3 d¨C12 d PI period, although there was nearly the same number of S. enteritidis cells over the 12 d period.

Last but not least, rapid identification of Salmonella enteritidis based on a specific real-time PCR amplifying species specific DNA sequence is a wonderful tool for clinical diagnosis.

The authors believe that this study will help to increase understanding of the mechanisms of Salmonella enteritidis infection in vivo and illustrate the need for further research into how to prevent and treat Salmonella enteritidis infection, especially by developing new treatment medicines.

More about the study can be found in a research article to be published on February 7 2008 in the World Journal of Gastroenterology.

Reference: Deng SX, Cheng AC, Wang MS, Cao P, Yan B, Yin NC, Cao SY and Zhang ZH. Quantitative studies of the regular distribution pattern for Salmonella enteritidis in the internal organs of mice after oral challenge by a specific real-time polymerase chain reaction. World J Gastroenterol 2008; 14(5): 782-789
http://www.wjgnet.com/1007-9327/14/782.asp

Correspondence to: Professor An-Chun Cheng, Avian Diseases Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Yaan 625014, Sichuan Province, China. chenganchun@vip.163.com
Telephone: +86-835-2885774 Fax: +86-835-2885774

World Journal of Gastroenterology (WJG), a leading international journal in gastroenterology and hepatology, has established a reputation for publishing first class research on esophageal cancer, gastric cancer, liver cancer, viral hepatitis, colorectal cancer, and H pylori infection for providing a forum for both clinicians and scientists. WJG has been indexed and abstracted in Current Contents/Clinical Medicine, Science Citation Index Expanded (also known as SciSearch) and Journal Citation Reports/Science Edition, Index Medicus, MEDLINE and PubMed, Chemical Abstracts, EMBASE/Excerpta Medica, Abstracts Journals, Nature Clinical Practice Gastroenterology and Hepatology, CAB Abstracts and Global Health. ISI JCR 2003-2000 IF: 3.318, 2.532, 1.445 and 0.993. WJG is a weekly journal published by WJG Press. The publication dates are the 7th, 14th, 21st, and 28th day of every month. The WJG is supported by The National Natural Science Foundation of China, No. 30224801 and No. 30424812, and was founded with the name of China National Journal of New Gastroenterology on October 1, 1995, and renamed WJG on January 25, 1998.

The WJG Press mainly publishes World Journal of Gastroenterology.