1. salmonella
Pathogenesis..

2. PATHOGENICITY OF SALMONELLAE
Clinical syndromes caused by Salmonellae in human beings:
A. Enteric fever B. Gastroenteritis (food poisoning)
C. Salmonella septicemia

3. ENTERIC FEVER
The term ENTERIC FEVER includes TYPHOID FEVER – caused by S typhi
2. PARATYPHOID FEVER – caused by
S paratyphi A, B & C

4. Contd.. Enteric fever is endemic in all over India.
With a proportion of TYPHOID to PARATYPHOID A about 10 : 1.
Paratyphoid B is rare and Paratyphoid C is very rare.

5. Typhoid Fever Typhoid fever, also known as typhoid
Other names: abdominal typhus,  infantile remittant fever,  slow fever,  nervous fever,  pythogenic fever, etc.

6. Contd..
Typhos in Greek means, smoke and typhus fever got its name from smoke that was believed to cause it.
Typhoid means typhus-like and thus the name given to this disease.
The term Typhoid was given by Louis (1829) to distinguish it from typhus fever.
Eberth described the typhoid bacillus in spleen sections and mesenteric lymph nodes from a patient who died from typhoid and Gaffky isolated it in pure cultures.

7. SALMONELLA
Electron microscopy

8. Epidemiological types
Epidemiology
Epidemiological types
Endemic
Epidemic

9. WORLD WIDE DISTRIBUTION

10. Contd.. Source : Case of Typhoid or carriers in frequent.
Infective material : Contaminated food or water.
Route of infection : Ingestion of contaminated food or water.

11. Carrier state..
CARRIERS are more important in the transmission of the disease.
Types of carriers: Convalescent carriers Temporary carriers Chronic carriers
Convalescent carriers shed bacilli in feces for 3 WEEKS to 3 MONTHS after clinical cure.
Temporary carriers shed bacilli for more than 3 MONTHS but less than A YEAR.
Chronic carriers shed bacilli for over A YEAR.

12. Contd..
2-4 % of patients become Chronic carriers, esp. women over 40yrs.
Food handlers or cooks that become carriers are particularly dangerous.
The best known example was Mary Mallon, named for nick as TYPHOID MARY.
She caused at least 7 outbreaks in 15 yrs affecting over 200 people.

13. Mary Mallon
in a newspaper illustration

14. Bacilli persist in gall bladder or kidney are shred out
Carriers
Fecal (Gall bladder)
Urinary (Kidney)

15. Pathogenesis
Median Infective Dose (ID50) is about to bacilli in human volunteers.
The course of organism in the body is as follows.

16. MESENTERIC LYMPHNODES THORACIC DUCT (Multiplication)
BACILLI
MICRO VILLI OF ILEUM
PENETRATION
PHAGOCYTOSIS
MESENTERIC LYMPHNODES
THORACIC DUCT (Multiplication)
BLOOD STREAM (Transient Bacteremia)
LIVER, G.B., SPLEEN, B.M., L.N., LUNGS.
MASSIVE BACTEREMIA

18. Clinical Course..
Incubation period is usually 7-14 days, but may range 3-56 days according to dose of infection.
Clinical course: From Mild Undifferentiated Pyrexia (AMBULANT TYPHOID)
Rapidly fatal disease

19. Clinical features.. Gradual Onset of head ache malaise anorexia
Typical features: Step ladder pyrexia
Relative bradycardia
Toxemia

20. Contd.. A soft, palpable spleen is a constant finding
Hepatomegaly is also common
Rose spots that fade on pressure appear on skin during 2nd or 3rd week.

21. Rose spots

22. Bile is a good culture medium for the bacillus, it multiplies
abundantly in GALL BLADDER
INTESTINES
involves the PAYERS PATCHES
LYMPHOID FOLLICLES

23. INFLAMMED PAYERS PATCHES
NECROSIS
SLOUGH OFF
TYPHOID ULCERS

24. ULCERATION OF
BOWEL
PERFORATION
HEMORRHAGE

25. Causation Ingestion of organisms Colonization of lower intestine
Mucosal invasion
Acute inflammation
Activation of Adenyl cyclase
Fluid production
Diarrhea
Causation

26. Complications of the disease
Intestinal perforation
Hemorrhage
Circulatory collapse
Bronchitis or Bronchopneumonia is always found.
Psychoses
Meningitis
Cholecystitis
Arthritis
Abscesses

27. Contd.. Periostitis Nephritis Hemolytic anemia Venous thromboses
Peripheral neuritis
Osteomyelitis is rare sequel.

28. Convalescence & Relapse
Convalescence is slow
In 5-10% of cases relapse occurs during convalscence
Relapse rate is higher in patients treated early with Chloramphenicol.

29. Paratyphoid fever Resembles typhoid fever but is generally milder
Caused by S. paratyphi A and B, rarely by S. paratyphi C which is often associated with frank septicemia in supporative complications.

30. Salmonella Gastroenteritis
Food poisoning.
Zoonotic disease.
Caused by any Salmonella except S. typhi.
Pathogenic Species:
1. S typhimurium (most common)
2. S enteritidis

31. Pathogenesis
Source: Poultry, Meat, Milk and its products, esp., Eggs and its products (as the bacteria can enter through the shell if eggs are contaminated and grow inside), uncooked vegetables.
Route: Ingestion
Gastroenteritis may occur without food poisoning as in cross infection in hospitals.

32. Clinically.. Short incubation period of 24hrs or less.
Featured by Diarrhea, Vomiting, Abdominal pain, Fever.
Diarrhea: May vary from one or more loose stools to an acute Cholera like
Usually subsides in 2-4 days resembles and dysentery.

33. Salmonella Septicemia
Caused by: S choleraesuis
Focal supporative lesions:
Osteomyelitiss,
Deep abscesses,
Endocarditis,
Pneumonia,
Meningitis.