•
community acquired • otherwise healthy people
– Klebsiella pneumoniae
respiratory diseases prominent capsule
–urinary tract infection –fecal contamination
E. coli Proteus
–
urease degrades urea urease degrades urea
–
alkaline urine alkaline urine
Enterobacteriaceae Enterobacteriaceae
•
gram negative facultative anaerobic rods gram negative facultative anaerobic rods
– –
oxidase negative no cytochrome oxidase oxidase negative no cytochrome oxidase
• E. coli
–
lactose positive
– not usually identified – lactose positive sp. common, healthy intestine
• Shigella, Salmonella,Yersinia
– lactose negative – identified
Feces Feces
•
other sites other sites
– identified biochemically
identified biochemically
Serotypes Serotypes
reference laboratory reference laboratory
–
antigens antigens
O lipopolysaccharide O lipopolysaccharide
H flagellar H flagellar
K capsular K capsular
Escherichia coli Escherichia coli
Toxins: two types of enterotoxin; Shiga-type toxin; Enteroaggregative ST-like toxin; Hemolysin
s; Endotoxin
Type III secretion system
Adhesions –colonization factors ; both pili or fim briae ;non-fimbrial factors involved in attachmen
t. There are at least 21 different types of adhesion s.
Virulence factors that protect the bacteria from h ost defenses: CapsuleIron capturing ability enter
ochelin
Outer membrane proteins
mannose mannose
Type 1 Type 1
•
galactose galactose
–
glycolipids glycolipids
–
glycoproteins glycoproteins
P P
E.coli-urinary tract infection E.coli-urinary tract infection
Is the leading cause of urinary tract infections which can lead to Is the leading cause of urinary tract infections which can lead to
acute cystitis bladder infection and pyelonephritis kidney infection. acute cystitis bladder infection and pyelonephritis kidney infection.
E.coli-Meningitis and Sepsis E.coli-Meningitis and Sepsis
Neonatal meningitis – is the leading cause of neonatal meningitis and septicemia
with a high mortality rate. Usually caused by strains with the K1 capsular
antigen.
Enteropathogenic Enteropathogenic
E. coli E. coli
fever
infant diarrhea
vomiting
nausea
non-bloody stools
Destruction of surface microvilli
1.
loose attachment mediated by bundle f orming pili Bfp;
2.
Stimulation of intracellular calcium lev el;
3.
rearrangement of intracellular actin,
Enterotoxigenic Enterotoxigenic
E. coli E. coli
