Enterobacteriaceae

Question 1

general characteristics of enterobacteriaceae

Answer 1

largest group of straight gram negative bacilli
motile (peritrochous) or non motile
produces endotoxin (LPS)
prosduce bacteriocins (toxic compounds that kill surrounding species)
Possess antigens O,H, and K

Question 2

o= somatic

Answer 2

protects MO against host resistant factors, lipopolysacchride- heat stable
major cell wall antigen (IgM against O)
150 different O antigens
Lipid A portion is released because of antibiotic treatment and immune response
Lipid A is responsible for fever, hypotension, leukopenia, DIC and all are associated with septic shock

Question 3

K= Capsular (Vi antigen)

Answer 3

resists phagocytosis
100 different K antigens 
few are protein in nature- heat liable 
may interfere with direction of O antigen (boil to remove) 
Most arre polysaccharide- heat stable

Question 4

H= flagellar

Answer 4

associated with motility
serotypes- divisions based on antigentic relatedness
biotypes- strains of same serotype with different biochemical characteristics

Question 5

describe coliforms and describe their importance

Answer 5

gram negative, fermentative and inhabitants of the intestinal tract which maintain normal flora and compete against pathogens