Salmonella enterica

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Salmonella enterica
S. enterica Typhimurium colonies on a Hektoen enteric agar plate
S. enterica Typhimurium colonies on a Hektoen enteric agar plate
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Enterobacteriales
Family: Enterobacteriaceae
Genus: Salmonella
Species: S. enterica
Binomial name
Salmonella enterica
(ex Kauffmann & Edwards 1952)
Le Minor & Popoff 1987
This page is about microbiologic aspects of the organism(s).  For clinical aspects of the disease, see Typhoid fever.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aysha Anwar, M.B.B.S[2]

Overview

Salmonella enterica is a rod shaped, flagellated, Gram-negative bacterium, and a member of the genus Salmonella.[1] S. enterica has an extraordinarily large number of serovars or strains—up to 2000 have been described.[2] Salmonella Typhi is a serovar of Salmonella enterica and the cause of the disease typhoid fever.[3][4][5][6]

Serovars

  • S. enterica has an extraordinarily large number of serovars or strains—up to 2000 have been described.[2]
  • Salmonella enterica Serovar Typhi (historically elevated to species status as S. typhi) is the disease agent in typhoid fever.[3][4][5][6][7][8]
  • Other serovars such as Typhimurium (also known as S. typhimurium) can lead to a form of human gastroenteritis sometimes referred to as salmonellosis.
  • The genome sequences of serovars Typhi[9] and Typhimurium LT2[10] have been established. Also an analysis of the proteome of Typhimurium LT2 under differing environmental conditions has been performed [11]
  • Other Salmonellae which may cause symptoms similar to typhoid fever include:
  • Salmonella Paratyphi A
  • Salmonella Paratyphi B
  • Salmonella Paratyphi C
  • Salmonella choleraesuis

Salmonella Typhi

Salmonella Typhi is a serovar of Salmonella enterica and the cause of the disease typhoid fever.[3][4][5][6][7][12] fecal-oral route

Features of Salmonella Typhi[13][14][15]

  • O polysaccharide antigen
  • H flagellar antigen
  • Vi outer capsular polysaccharide antigen

Transmission of Salmonella typhi

  • Fecal-oral route
  • Excretion in human feces causing transmission by contaminated water, food, or by person-to-person contact.

Epidemiology

Most cases of salmonellosis are caused by food infected with S. enterica, which often infects cattle and poultry, though also other animals such as domestic cats and hamsters[16] have also been shown to be sources of infection to humans. However, investigations of vacuum cleaner bags have shown that households can act as a reservoir of the bacterium; this is more likely if the household has contact with an infection source, for example through members working with cattle or in a veterinary clinic.

Raw chicken and goose eggs can harbor salmonella enterica, initially in the whites of the eggs, although most eggs are not infected. As the egg ages at room temperature, the yolk membrane begins to break down and salmonella enterica can spread into the yolk. Refrigeration and freezing do not kill all the bacteria, but substantially slow or halt their growth. Pasteurizing (briefly heating to a specific temperature) and irradiation are used to kill salmonella for commercially produced foodstuffs containing raw eggs such as ice cream. Foods prepared in the home from raw eggs such as mayonnaises, cakes and cookies can spread salmonella if not properly cooked before consumption. See Egg (food).

Space bacteria

On September 25, 2007, Cheryl Nickerson (Center for Infectious Diseases and Vaccinology) at Arizona State University stated that space bacteria Salmonella typhimurium (food bugs, on their 12-day Atlantis orbiter flight, September 2006) were found to change the way they expressed 167 genes (regulated by a protein Hfq). It gained 3 times virulence than on earth.[17]

Also see

Gallery


References

  1. ↑ Giannella RA (1996). Salmonella. In: Baron's Medical Microbiology (Barron S et al, eds.) (4th ed. ed.). Univ of Texas Medical Branch. (via NCBI Bookshelf) ISBN 0-9631172-1-1.
  2. ↑ 2.0 2.1 Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.). McGraw Hill. ISBN 0-8385-8529-9.
  3. ↑ 3.0 3.1 3.2 Arndt MB, Mosites EM, Tian M, Forouzanfar MH, Mokhdad AH, Meller M; et al. (2014). "Estimating the burden of paratyphoid a in Asia and Africa". PLoS Negl Trop Dis. 8 (6): e2925. doi:10.1371/journal.pntd.0002925. PMC 4046978. PMID 24901439.
  4. ↑ 4.0 4.1 4.2 Maskey AP, Day JN, Phung QT, Thwaites GE, Campbell JI, Zimmerman M; et al. (2006). "Salmonella enterica serovar Paratyphi A and S. enterica serovar Typhi cause indistinguishable clinical syndromes in Kathmandu, Nepal". Clin Infect Dis. 42 (9): 1247–53. doi:10.1086/503033. PMID 16586383.
  5. ↑ 5.0 5.1 5.2 Oboegbulam SI, Oguike JU, Gugnani HC (1995). "Microbiological studies on cases diagnosed as typhoid/enteric fever in south-east Nigeria". J Commun Dis. 27 (2): 97–100. PMID 7499779.
  6. ↑ 6.0 6.1 6.2 Vollaard AM, Ali S, Widjaja S, Asten HA, Visser LG, Surjadi C; et al. (2005). "Identification of typhoid fever and paratyphoid fever cases at presentation in outpatient clinics in Jakarta, Indonesia". Trans R Soc Trop Med Hyg. 99 (6): 440–50. doi:10.1016/j.trstmh.2004.09.012. PMID 15837356.
  7. ↑ 7.0 7.1 Wain J, Hendriksen RS, Mikoleit ML, Keddy KH, Ochiai RL (2015). "Typhoid fever". Lancet. 385 (9973): 1136–45. doi:10.1016/S0140-6736(13)62708-7. PMID 25458731.
  8. ↑ http://www.cdc.gov/typhoid-fever/health-professional.html
  9. ↑ Parkhill J; et al. (2001). "Complete genome sequence of a multiple drug resistant Salmonella enterica serovar Typhi CT18". Nature. 413 (6858): 848–52. PMID 11677608 doi:10.1038/35101607.
  10. ↑ McClelland M; et al. (2001). "Complete genome sequence of Salmonella enterica serovar Typhimurium LT2". Nature. 413 (6858): 852–6. PMID 11677609 doi:10.1038/35101614.
  11. ↑ Adkins JN; et al. (2006). "Analysis of the Salmonella typhimurium Proteome through Environmental Response toward Infectious Conditions". Molecular and Cellular Proteomics. 5: 1450–1461. PMID 16684765.
  12. ↑ http://www.cdc.gov/typhoid-fever/health-professional.html
  13. ↑ Fàbrega, Anna, and Jordi Vila. "Salmonella enterica serovar Typhimurium skills to succeed in the host: virulence and regulation." Clinical microbiology reviews 26.2 (2013): 308-341.
  14. ↑ Grossman, Daniel A., et al. "Flagellar serotypes of Salmonella typhi in Indonesia: relationships among motility, invasiveness, and clinical illness." Journal of Infectious Diseases 171.1 (1995): 212-216.
  15. ↑ Schmoldt A, Benthe HF, Haberland G (1975). "Digitoxin metabolism by rat liver microsomes". Biochem Pharmacol. 24 (17): 1639–41. PMID 10.1056/NEJMra020201 DOI: 10.1056/NEJMra020201 Check |pmid= value (help).
  16. ↑ Swanson SJ, Snider C, Braden CR; et al. (2007). "Multidrug-resistant Salmonella enterica serotype Typhimurium associated with pet rodents". 356 (1): 21&ndash, 28.
  17. ↑ BBC NEWS, Space bugs become more dangerous
  18. ↑ 18.0 18.1 18.2 "Public Health Image Library (PHIL)".

External links


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