University:
Swansea University
Course:
PM134 | Microbiology
Academic year:

2023
Views:

452

Pages:

2
Author:

Yasin N.

ENTERIC FEVER INTRO Definition: Infection acquired by ingestion, involving cells of RE system by S.typhi and S.paratyphi leading to septicaemia/bacteremia and characterized by undifferentiated pyrexia to a typically fatal disease. 1. ENTERIC FEVER Typhoid Paratyphoid Fever 2. Caused by Salmonella typhi and Salmonella paratyphi A respectively 3. R0e07qrt7e7eqtSpreads through contaminated food, water and milk Brief on Salmonella: Family - Enterobacteriaceae Gram NEGATIVE Bacteria Fermentative in metabolism Catalase +ve Oxidase-ve Motile In MacConkey agar produce non lactose fermenting colourless colonies More than 2000 serotypes all of which are pathogenic in humans or other animals S. typhi and S. paratyphi A are strictly human pathogens Classification 1 : Based on disease Typhoidal-which causes the enteric Fever, restricted to human hosts and further can be classified into S. typhi S. Paratyphi Non Typhoidal which causes food poisoning Classification.2 : Based on presence of different somatic (O) and flagellar Antigen (H) (KAUFFMAN-WHITE) There are 67 serogroups each containing "group-specific O antigen" Virulence factors: O-Antigen-It's a somatic antigen, LPS (lipopolysaccharide) in composition It is immunogenic (Antibody can be produced) H-Antigen-Its a flagellar antigen which helps in motility of the bacteria It is highly Immunogenic VI- Antigen - It's a surface envelope antigen consisting of polysaccharide Its also called surface envelope antigen Vi stands for its virulence nature Poorly immunogenic Inhibits phagocytosis Inhibit complement activation Resist action of peroxidase Note: These pathogens have the ability to survive within the Macrophage!