Salmonella Tphi
- 3. What is Typhoid fever? • Typhoid fever is an illness caused by the bacterium Salmonella Typhi (S. Typhi). • It infects your small intestines (gut) and causes high fever, stomach pain and other symptoms. • Typhoid fever is also called enteric fever.
- 4. • Salmonella is a gram negative rods genus belonging to the Enterobacteriaceae family. • Within 2 species, Salmonella bongori and Salmonella enterica, over 2500 different serotypes or serovars have been identified to date.
- 6. Important properties of Salmonella species • Gram-negative rods • Do not ferment lactose • Antigens of Salmonella species Cell wall O antigen Flagellar H antigen Capsular Vi (virulence) antigen)
- 8. Sources and transmission • Salmonella bacteria are widely distributed in domestic and wild animals. • They are prevalent in food animals such as poultry, pigs, and cattle; and in pets, including cats, dogs, birds, and reptiles such as turtles. • Person-to-person transmission can also occur through the faecal-oral route.
- 9. Pathogenesis Incubation Period: 7 to 23 days (average 10 to 14 days)
- 11. Pathophysiology
- 12. Lab Diagnosis
- 13. Colony characteristics • Aerobic or facultative anaerobes • Optimal temperature 37°C • Optimal pH • Nutrient broth: Uniform turbidity • Blood agar: Colonies 2 to 3 mm, circular, low convex, smooth, translucent, and non-hemolytic • MacConkey agar: Non- lactose fermenter ( colorless colonies) • Deoxycholate Citrate Agar (DCA): Non-lactose fermenter colonies • Wilson and Blair bismuth sulfite medium: Jet black colonies with a sheen
- 14. Culture Media
- 16. API (Analytical Profile Index) 20E Principle: The strip consists of 20 microtubes containing dehydrated substrates. The tests are inoculated with bacterial suspensions that reconstitutes the media. During incubation, specific bacterial metabolites are produced that can be detected via color changes. Based on this information, bacterial identification is often possible.
- 17. Treatment • Ciprofloxacin • Ampicillin • Chloramphenicol • Trimethoprim-sulfamethoxazole • Azithromycin • Ceftriaxone
- 18. Vaccine • TAB vaccine : • It contains Salmonella Typhi 1000million/ ml, Salmonella Paratyphi A 750 million/ ml and Salmonella Paratyphi B 750 million/ ml. • Streptomycin dependent strain vaccine • Killed vaccine • Ty21a (oral vaccine)