Typhoid fever deepa babin


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Typhoid fever deepa babin

  1. 1. Diagnosis of deepababin@gmail.comTyphoid FeverA Clinical Problem Based Learning Deepa Babin 1
  2. 2. Case study• A 20 years old male medical student presented with fever since one week. The temperature chart shows step ladder pattern of fever. On clinical examination patient is having mild hepatomegaly. deepababin@gmail.com• 1. What can be your provisional diagnosis?• 2. What are the microbiological investigations for diagnosing this condition?• 3. What is the importance of Antibiotic sensitivity in this condition?• 4. How you will prevent this infection? 2
  3. 3. Observe the Step Ladder Pattern of Temperature deepababin@gmail.com 3
  4. 4. Answer• It can be case of Enteric feverMicrobiological diagnosis• Specimens: Blood , Bone marrow ,Blood clot, Stool and deepababin@gmail.com Urine can be cultured• The best isolation rates from blood have been seen in the first week of illness, with faeces in the second week and with urine the third week of illness. 4
  5. 5. Blood Cultures in Typhoid Fevers• Bacteremia occurs early in the disease• Blood Cultures are positive in1st week in 90%2nd week in 75%3rd week in 60%4th week and later in 25%
  6. 6. Isolation of the organism Blood culture- Castaneda Biphasic medium• Add a minimum of 10 ml of venous blood from an adult patient to each of 50 ml of Bile broth and Biphasic medium with nutrient agar as slant and Brain heart deepababin@gmail.com infusion broth as liquid medium• From children at least 5 ml blood should be inoculated in each of the bottles.• Incubate the inoculated media at 37oC overnight and subculture into• MacConkey agar 6• Blood agar
  7. 7. Further Incubation up to 7 days• Incubate up to 7 days if subcultures fail to yield any bacterial growth.• Subculture again on day 7 and if no deepababin@gmail.com growth is obtained blood culture may be declared as negative for enteric fever bacilli.• Periodic subcultures are made after day 2, 5 and 7 on MacConkey agar. 7
  8. 8. Clot culture• The clot culture has following advantages over blood culture namely• Serum is available for antibody titration.• The clot can be put in blood culture bottles and deepababin@gmail.com can be broken either mechanically or by adding streptokinase, if available.Urine culture• Urine culture is positive in a quarter to one third of cases, but there seems to be no regular 8 excretion pattern in the urine
  9. 9. Clot culture• Clot cultures are more productive in yielding better results in isolation. deepababin@gmail.com• A blood after clotting, the clot is lysed with Streptokinase ,but expensive to perform in developing countries. 9
  10. 10. Culture Medias Mac Conkeys agar Deoxycholate citrate agar (DCA) Selenite F broth as enrichmentmedium.Cultural characters deepababin@gmail.com DCA - pale yellow colonies, 2-3 mmin diameter, moist, circular andsmooth convex surface.MacConkeyagar-non lactosefermenting colonies 10
  11. 11. Salmonella on Mac Conkeys agar deepababin@gmail.com 11
  12. 12. Salmonella on XLD agar deepababin@gmail.com 12
  13. 13. Biochemical reactions I M Vi C TSI U _ + _ _ K/A H2s _ • Catalase positive and Oxidase negative. • I M Vi C _ + _ _ • TSI - K/A with H2S deepababin@gmail.com • Urease Negative • Gram smear-Gram negative bacilli 13
  14. 14. Slide agglutination• On the basis of biochemical reactions, the organism has been identified as Salmonella; its identity can be confirmed with slide agglutination test, using polyvalent O and polyvalent H antisera against salmonellae. deepababin@gmail.com• For identification monovalent O specific antiserum for S.typhi is factor 9.• To perform this test 1 drop each of normal saline is placed at two different sites on a clean glass slide. 14
  15. 15. Slide agglutination tests• In slide agglutination tests a known serum and unknown culture isolate is mixed, clumping occurs within few minutes• Commercial sera are available for detection of A, B,C1,C2,D, and E.
  16. 16. Slide agglutination• A loopful of biochemically suspect colony of Salmonella is emulsified in both. One of these is kept as central and another is tested first with polyvalent O antiserum against Salmonella. deepababin@gmail.com• If this gives visible agglutination within 2 minutes, the process is repeated with polyvalent H antiserum and then with factor 9 antiserum 16
  17. 17. Other methods of Diagnosis of Typhoid fever• WIDAL TEST• Serum agglutinins raise abruptly during the 2nd or 3rd week.The widal test detects antibodies against O, H,AH,BH antigens• Two serum specimens obtained at intervals of 7 – 10 deepababin@gmail.com days to read the raise of antibodies.• Serial dilutions on unknown sera are tested against the antigens for respective Salmonella• False positives and False negative limits the utility of the test O > 1 in 160 H > 1 in 320TyphidotDetects specific IgM and IgG antibodies to S. typhi 17
  18. 18. . Antimicrobial susceptibility testing• The emergence and spread of S.typhi resistant to multiple antibiotics shows the need for susceptibility testing.• Multi-drug resistant typhoid fever has become endemic in many developing countries. deepababin@gmail.com• Resistant to Chloramphenicol, Ampicillin and Trimethoprim sulfamethoxazole.• Choice of drug • Fluoroquinolones (ciprofloxacin,Ofloxacin) Third gen Cephalosporins(Cefotaxime,Ceftri 18 azone,Ceftazidime)
  19. 19. BACTEK and Radiometric based methods are in recent use • BACTEK methods in isolation of Salmonella is a rapid and sensitive method in early diagnosis of Enteric fever. • Many Microbiology Diagnostic Laboratories are upgrading to Bactek methods
  20. 20. Prevention• Good Sanitary measures• Typhoid vaccine(TAB Vaccine) Heat inactivated phenol preserved vaccine. deepababin@gmail.com• Divalent vaccine in India• Dosage- Two doses four weeks apart with single booster dose every three years 20
  21. 21. • Programme created for Medical andParamedical students for orientation on deepababin@gmail.com Clinical Based Learning • Email • deepababin@gmail.com 21