A child with suspected colienteritis was delivered to the infectious diseases hospital. Colibacillus was obtained from the child’s feces. How to determine whether this bacillus is of pathogenic variety?

Answer options

1. By means of bacteriophage typing
2. Based on the nature of its growth in Endo medium
3. Agglutination reaction with serum 0
4. Based on its biochemical properties
5. Microscopy of stained smears

Explanation

Organisms can be isolated from blood, bone marrow, urine, and tissue biopsy from the rose spots if present; antibodies to O, Vi, and H antigens in a patient's serum can be detected by agglutination (Widal test).