Enteric Fever- Lab Diagnosis

SLECIMEN FLEEP collection Demonstration of WIDAL TEST Lobed 1st worklact.) Scrum Antibodies 11 and 0 Abc are deteited and by usis As its TO contigue ofs types Mdculor methods TH Cld culture All Martim it's propers B artiger ale liph Blood is certify tPIR 21 icen Mantager of used favids 1,4 Culture medium LAB DIAGNOSS of Resent Menephasis or exphasis (consented) INTERIC FEVER Deffermation Granulas dally clumps (diskline) (Newyapperance corplenes Jully on Blood ager H asgination Nor moist idonies semonetration cetten. waly champs ago Round adows of seruum transluted pole Antigar Fall positive Amnester regree fearns ELISA Fake negallie Rolly (letwork) Late (After owers) sur P Stool and Uine Cultures cavele crantitatics 3rd a 6th week Enrichment brother sciente F both III otherefecimens Bone know Slide Aggleticsion test Wilson pair - Brilliant green Aismith Doorevalooperate Identification of Salmarth suifite ofdem Jet bach colored intonies at give level ing 3.Typhi with metallic sheen. pdyralent 0 antisera pratyphi Pale edor INC color chase

4 methods 1. Specimen collection 2. Demonstration of serum Antibodies 3. Demonstration of serum Antigens 4. Molecular methods SPECIMEN CULTURE Blood culture and serology Stool culture Urine culture Ideal specimen of collection If the patient comes within first week Blood culture followed by fecal culture If the patient comes after a week within 10 days Blood serology preferred followed by feces culture Widal test ( o and H antigens) Diagnosis of Enteric fever Widal test Bone marrow 90% Urine culture Urine culture 25% 10% Feces culture Feces culture Decreasing 80% 50% positivity Blood culture 80 to 90% 0 I 2 4 5 >5 Weeks labpeds net

MNEMONIC-BASU B - Blood culture - 1st week A - Agglutination (WIDAL) -2nd week S Stool 4th week U - Urine 3rd week WIDAL test Titer - The cut-off of titer varies from place to place, in western countries 1/20 itself is taken as positive whereas in endemic countries like India : H agglutinin titer more than 200 : o agglutinin titer more than 100 This is because due to prior exposure people will always have some baseline antibodies! NOTE : In culture media - selective media used:- 1. Low selective media - MacConkey Agar 2. Highly selective media - DCA agar ( NLF colonies with black centre ) & XLD Agar (red colonies with black centre ) & Wilson Blair's method ( already described in pic) DETECTION OF CARRIERS : Done by detection of Vi antibodies; even a titer 1:10 is considered significant but confirmation must be made by culture