Salmonella

Salmonella

Introduction

According WHO, the primary cause of food-borne illness around the globe is associated with the bacterium Salmonella (WHO Salmonella, 2013). In the United States alone, there are about 42,000 new cases reported each year. Furthermore, since many of the mild form of diseases are often missed or left undiagnosed, the actual number is far greater. The infection from the bacterium Salmonella occurs more frequently in summers rather than winters. Moreover, young children, older adults, as well as people with impaired immune system, are more susceptible to infection. The mortality rate is also reported being higher in children, oftentimes leading to death (CDC, 2010).

Discussion

Salmonellae are motile, gram-negative bacilli, belonging to genus Salmonella. It was first isolated in 1884 by Daniel E. Salmon from pigs. It is a potential enteric pathogen closely-related to Escherichia coli. The food-borne illness from the bacterium Salmonella is popularly known as Salmonellosis. There are various serotypes of the bacterium. However, in the United States the Salmonella Typhimurium, Salmonella Enteritidis are the two most common types (CDC, 2010). Nonetheless, the bacterium can produce a wide array of diseases, including enterocolitis, typhoid fever, endovascular infections, bacteremia, and focal infections like osteomyelitis (Klochko, 2011).

Pathophysiology of Salmonella

Salmonellosis is caused by consumption of food contaminated with the bacteria Salmonella Typhimurium or Salmonella Enteritidis. Some of the usual sources include beef, chicken, and eggs. In a recent study, it was reported that almost 182,060 cases of enteritis resulted due to consumption of egg shells in the year 2000, in the United States. In addition, improper handling of vegetables, fruits, dairy products and shellfish have also been linked to Salmonella transmission (Klochko, 2011). Furthermore, human-to-human and animal-to-human can also result. A CDC report on the transmission of the bacterium in children from pet amphibians and reptiles is approximately 100,000 across the US (Pet Turtles: Cute But Contaminated with Salmonella, 2012). Outbreaks have also been linked to handling of poultry, cats, and hedgehogs.

For the diseases to occur, Salmonella is required in large inoculums to overcome the gastric acidity and to compete with normal flora of the intestine. The infective dose of bacteria is 106 bacterial cells; however, in people with low gastric acidity, such older adults, the infective dose can be reduced to 10³. After ingestion, Salmonella attaches to M cells of Peyer patches via fimbriae or pili. Then, through receptor-mediated endocytosis, it is transported and released in to lamina propria ...