Enteric fever

1. Enteric fever 1 ENTERIC FEVER Prabin Shah BScMLT , MSc (Biochemistry)

2. Typhoid fever, commonly just typhoid, is a common worldwide illness, transmitted by the ingestion of food or water contaminated with the  feces of an infected person . This fever received various names, such as gastric fever, the bends, abdominal typhus, infantile remittent fever, slow fever, nervous fever , pathogenic fever, etc. Enteric fever 2 INTRODUCTION

3. The salmonella bacilli was first described by Salmon and Smithin the year 1885 . In 1906, Irish immigrant Mary Mallon worked as a cook and was a carrier. Thus earned the nickname " Typhoid Mary . She died of a stroke after 23 years . Enteric fever 3 H istory

4. The term enteric fever or typhoid fever refers to a communicable disease, found only in man and includes both typhoid fever caused by S.Typhi and paratyphoid fever caused by S.Paratyphi A, B and C . It is an acute generalized infection of the reticulo -endothelial system, intestinal lymphoid tissue, and the gall bladder. Enteric fever 4 DEFINITION

5. GNB Motile Non sporing Non capsulated Enteric fever 5 MORPHOLOGY

6. Killed at 60°C in 15 mins Boiling, chlorination of water and pasteurisation of milk also destroys the bacilli. Survive in water and ice for weeks Enteric fever 6 RESISTANCE

7. 3 types of antigens; Flagellar antigen ‘H’ Somatic antigen ‘O’ Surface antigen ‘Vi’ Enteric fever 7 ANTIGENIC STRUCTURE

8. " O"-group Sero type "O" antigens Phase 1 (motile) "H" antigens Phase 2 (non-motile) "H" antigens Old New A 2 S.Paratyphi A 1, 2 ,12 a no phase 2 antigen B 4 S. Paratyphi B 1, 4 ,5,12 b 1,2   S. Typhimurium 1, 4 ,5,12 i 1,2 C 1 7 S. Paratyphi C 6,7 c 1,5   S. Colerae-suis 6,7 c 1,5 C 2 8 S.muenchen 6,8 d 1,2 S.newport 6,8, 20 e, h 1,2 D 9 S. Typhi 9 ,12,Vi d no phase 2 antigen   S. Enteritidis 1, 9 ,12 g,m no phase 2 antigen   S. Gallinarum 1, 9 ,12 no phase 1 antigen no phase 2 antigen   S. Pullorum (1), 9 ,12 no phase 1 antigen no phase 2 antigen E 1 3,10 S. Anatum 3,10 e,h 1,6

9. H antigen( flagellar antigen) Ag is present in the flagella Heat labile protein Strongly immunogenic Produces large, loose, fluffy clumps. O antigen Lipo polysaccharide Identical to endotoxin Heat stable Produces compact, chalky, granular clumps. Less immunogenic Enteric fever 9

10. Vi antigen Surface antigen enveloping the O Ag is referred to as Vi Ag. Heat labile Acts as virulence factor by inhibiting phagocytosis, resisting complement activation and bacterial lysis . Poorly immunogenic. Not helpful in the diagnosis of enteric fever. Enteric fever 10

11. ENTERIC FEVER TYPHOID FEVER PARATYPHOID FEVER SEPTICAEMIA GASTROENTERITIS Enteric fever 11 PATHOGENESIS

12. TYPHOID FEVER The name typhoid was coined by Louis in 1829. Caused by S.typhi Acquired by the ingestion of contaminated food and water IP: 7-14 days Enteric fever 12 ENTERIC FEVER

13. Enteric fever is endemic in all parts of india . Typhoid fever occurs in 2 epidemiological types; endemic( occurs through out the year) epidemic( occur in endemic or non-endemic areas) 13 Epidemiology

14. Convalescent carriers shed the bacilli in feces for 3 weeks to 3 months. Temporary carriers Shed the bacilli for more than 3 months but less than a year. Chronic carriers Shed the bacilli over an year Fecal carrier the bacilli that persist in kidney or gall bladder are eliminated through feces Urinary carrier bacilli eliminated through urine, associated with urinary lesion such as calculi. Enteric fever 14 Types of carriers

15. Bacilli attaches to the epithelial cells of the intestinal villi in the small intestine. Penetrates to the lamina propria and sub mucosa Phagocytosed by the neutrophils and macrophages Bacteria resists and it enters into the mesenteric lymph nodes and multiply there via the thoracic duct and enters into the blood stream. A transient bacteremia follows and the internal organs like liver, gall bladder, spleen, bone marrow, lungs and kidney get infected. Enteric fever 15 Sequence of infection

16. Clinical features include; Mild pyrexia Headache Malaise Anorexia Coated tongue Abdominal discomfort with constipation/diarrhea Congestion of mucous membranes Hepatosplenomegaly with soft and palpable spleen. Step ladder pyrexia with relative bradycardia and leucopenia. Skin rashes known as rose spots may appear on the 2 nd and 3 rd week. Enteric fever 16

17. Rose spots Enteric fever 17

18. 2. PARATYPHOID FEVER Milder form than typhoid fever. Caused by S.paratyphi A,B and C Other salmonella causing enteric fever are; S.dublin S.barielly S.sendai S.enteritidis S.typhimurium S.eastbourne S.saintpaul S.panama Enteric fever 18

19. Specimen collection B lood Faeces Urine Aspirated duodenal fluid Bile Bone marrow Rose spots Pus from suppurative lesions CSF Sputum At autopsy cultures may be obtained from the gall bladder, liver, spleen, and mesenteric lymph nodes. Enteric fever 19 LAB DIAGNOSIS

20. Duration of disease Specimen examination % positivity 1 st week Blood culture 90 2 nd week Blood culture Faeces culture Widal test 75 50 Low titre 3 rd week Widal test Blood culture Faeces culture 80-100 60 80 Enteric fever 20 Specimens collection based on different phases of enteric fever

21. Gram stain is done GNB Non capsulated Motile with peritricous flagella except gallinarum and pullorum . Enteric fever 21 Microscopy

22. Grows on ordinary media Opt temp: 37°C pH: 6-8 Aerobic and facultative anaerobic. On nutrient agar Colonies are 2-3mm in diameter, circular, translucent, grey white in color, low convex and smooth. Enteric fever 22 III. Culture

23. On MacConkey’s agar and DCA Colorless colonies due to NLF colonies. Selective media Wilson and B lair bismuth sulphite medium Jet black colonies with metallic sheen are formed due to formation of hydrogen sulphide . Xylose lysine deoxycholate (XLD) Red colonies with black centres are seen Enrichment media Selenite F broth Tetrathionate broth (TTB) 23

24. Enteric fever 24

25. Ferments glucose and mannitol forming acid and gas except S.typhi produces only acid but no gas. Catalase positive Oxidase negative Indole is not produced Produces H 2 S in TSI agar except S. paratyphi A and S. cholerae-suis . Utilise citrate (except S.typhi & S.paratyphi A) MR positive VP negative Urea not hydrolysed Nitrate reduction test is positive Enteric fever 25 IV . BIOCHEMICAL REACTIONS

26. S.typhi S.Paratyphi A S.Paratyphi B S.Paratyphi C Glucose A AG AG AG Mannitol A AG AG AG Lactose - - - - Sucrose - - - - Indole - - - - Citrate - - + + MR + + + + VP - - - - H 2 S + - ++ + Enteric fever 26 Biochemical rxns to differentiate btw salmonella species

27. Positive in 90% of the cases in the first week of fever. 75% in second week 60% in third week Procedure 10ml of blood collected under aseptic conditions and transferred into blood culture bottles. Enteric fever 27 Blood culture

28. Blood has to be diluted with the culture media in the ratio of 1:10. Then incubated at 37°C overnight. Subculture done on BA and MCA More preferred method is the C astaneda’s method of blood culture. Enteric fever 28

29. Salmonella are shed in faeces during the infection and convalescence phase too. Generally faeces culture turn positive in the second week of infection. Sample is inoculated into one tube each of selenite and tetrathionate broth(enrichment media) Plated onto MCA, DCA, XLD, and Wilson-Blair medium. Enteric fever 29 Faeces culture

30. Frequency of getting a positive result is less when compared to that of blood and faeces . Generally seen as positive in the 2 nd and 3 rd weeks. Urine samples are centrifuged and deposit is inoculated into both enrichment and selective medium. Enteric fever 30 Urine Culture

31. 5ml of blood is withdrawn aseptically into sterile container and allowed to clot. Clot is broken up with a sterile glass rod and added to bile broth containing streptokinase(100units/ml) which digests the clot causing its lysis and thereby the bacteria are released from the clot. Enteric fever 31 Clot culture

32. It is an agglutination test for the detection of agglutinins (H and O) in patients with enteric fever. The antibodies begin to appear in serum at the end of 1 st week and rise during the 3 rd week of enteric fever. 2 specimens of sera are collected at an interval of 7 to 10 days to demonstrate the rising Ab titre . Enteric fever 32 WIDAL TEST

33. 2 types of tubes; Dreyer’s tube Felix tube Equal vol of 0.4ml of serial dilution of the serum(1:10 to 1:640) and the H and O antigens are mixed and incubated at 37°C for 4 hrs and read after overnight incubation in room temp. Control tubes with antigen and normal saline are included to check for auto agglutination. Enteric fever 33 Procedure

34. H agglutination - formation of loose, cotton wool clumps O agglutination – granular deposit at the bottom of the tube High dilution with carpet formation indicates the antibody titre against that particular Ag. Control tubes will show a compact deposit (button formation). Enteric fever 34

35. A loopful of the growth from nutrient agar slope is emulsified in 2 drops of saline on a slide. One emulsion acts as a control and other as a test. Agglutination is first carried out with the polyvalent O and the polyvalent H antisera. Positive agglutination indicates that the isolate belong to genus salmonella. Then if S.typhi is suspected, agglutination with O anti serum is done. Prompt agglutination indicates that the isolate belong to group D salmonella. S.typhi is confirmed by the agglutination with O anti serum. Enteric fever 35 SLIDE AGGLUTINATION TEST

36. Vaccinations TAB vaccine heat killed Polyvalent vaccine Dose schedule: 2 doses of 0.5ml at an interval of 4-6 weeks S/C followed by booster every 3 years. ii . Purified Vi polysaccharide vaccine( typhim -Vi) Dose schedule: single dose of 25µg injected I/M or S/C Causes minimal reaction. Enteric fever 36 PROPHYLAXIS

37. Live Oral typhoid vaccine Stable mutant of S.typhi Dose schedule: 3 doses on days 1,3,5 should be taken an hour before food, with a glass of water or milk . Oral ( typhoral ) vaccine is available as capsule . On ingestion, it initiates infection but self destructs after 4-5 cell divisions and thus cannot induce any illness. Enteric fever 37

38. Antibiotics such as; Chloramphenicol Streptomycin Tetracycline Ampicillin Amoxycillin Cotrimoxazole Are found effective in the treatment of typhoid fever. Enteric fever 38 Treatment

39. Showed resistance to chloramphenicol. Chloramphenicol resistant typhoid fever appeared in kerala in 1972. Multi drug resistant S.typhi is also becoming a major problem in india . These may cause nosocomial salmonellosis as septicaemia , meningitis, and suppurative lesions. Enteric fever 39 Drug resistance

40. A zoonotic disease Caused by S.typhi , S.typhimurium , S.enteritidis , S.indiana , S.newport , S.agona . Sources: poultry, meat, milk, eggs. Clinical features: diarrhea, vomiting, fever, abdominal pain. Enteric fever 40 Gastroenteritis

41. Certain salmonella may cause septicaemia with suppurative lesions such as deep abscess, osteomyelitis , pneumonia, endocarditis and meningitis. S.cholerae suis is the most important causative agent of salmonella septicaemia . Fulminating blood infection. Treatment with chloramphenicol. Enteric fever 41 Septicaemia

42. Text book of microbiology Ananthnarayan and Paniker’s Text book of microbiology C.P. Baveja Mackie and McCartney google Enteric fever 42 REFERENCE

43. THANK YOU Enteric fever 43