Enteric Bacteria: E.coli

Enterobactericeae

large rods (2-4 microns), easily grown in culture

Escherichia

Shigella

Salmonella
Klebsiella

Yersimia

Enterobactericeae location

lower GI tract, female urogenital tract, transients on skin, sepsis and endotoxic shock

Salmonella and shigella strict pathogens

not members of normal flora

Enterobactericeae clinical manifestations UTI

dysuria, frequent urination, spread to kidneys, fever, and flank pain, acute diarrhea, more common in women experienced in 40% of women’s lifetime

Enterobactericeae clinical manifestations dysentary

inflammatory diarrhea, blood and pus in stool, watery, cause dehydration

Enterobactericeae encounter

fecal-oral contamination, intermediary vehicles

7 Fs

food, feces, fluids, fingers, flies, fomites, fornification

Inoculum size

number of organisms required to cause disease

Inoculum size shigella dysenteriae

few hundred (small #, not typically found in the body)

easily transmitted person to person

E.coli (exterotoxigentic- ETEC) Inoculum size

100 million through food/water

Escherichia coli

most arivrulent, gram negative bacteria, facultative anaerobes, abundant in human intestine

Escherichia coli sterotypes

O- lipopolysaccharide (173 types)

H- Flagella (75 types)

K- Capsules (100 types)

Escherichia coli diagnosis

GI issues: diarrhea/dysentery, vomiting, loss of apetite,

history fecal-oral contamination

Escherichia coli symptoms

signs of infection- fever and inflammation

Escherichia coli UTI treatment

widespread resistance to ampicillin, effective antibiotics: sulfamethoxazole, fluroquinolines

Escherichia coli diarrhea treatment

antibiotics may help (except EHEC), antibiotics not prescribed in suspected EHEC increase subsequent development of HUS

advanced disease, stimulates toxin production

Rehydration therapy

Escherichia coli prevention

avoid fecal-oral contamination: reduce risk of acquiring of infection and foods and practices associated with outbreak

UPEC uropathogenic E.coli

reservoir for infection is intestinal tract: contaminants perineal or urethral area, trauma allows to penetrate bladder, enters urinary tract

UPEC uropathogenic E.coli fimbriae

virulence factor used to stick to walls of cells its infecting

UPEC uropathogenic E.coli complications

UTI, 90% of cystitis cases and 250,000 causes of pyelonephritis in USA

ETEC enterotoxigenic E.coli

traveler’s diarrhea, locals gain immunity (210 million cases, 380,000 deaths, children)

ETEC enterotoxigenic E.coli virulence factors

produce exotoxin (enterotoxin) under genetic control of plasmid

ETEC enterotoxigenic E.coli Heat-labil toxin/heat-stable toxin

causes release of water= water diarrhea

ETEC enterotoxigenic E.coli colonization factors

facilitate attachment to cellular receptors on GI

colonizes small intestine

ETEC enterotoxigenic E.coli symptoms

diarrhea usually not bloody nor leukocytes, no abdominal cramping

ETEC enterotoxigenic E.coli treatment

self-limiting, fluid replacement

ETEC enterotoxigenic E.coli prevention

Hot/cooked food, clean drinking water, better sanitation

EPEC, enteropathogenic E.coli

1st identified in hospital nursery outbreak in 1950s, but now disappeared in industrial nations, colonize small intestine

20% of diarrhea in bottle def infants under one year

EPEC, enteropathogenic E.coli cause

A/E lesions

A/E lesions

attachment and effacing

1. Make proteins allowing it to burrow into the cell

2. Type III secretion of Tir and other effectors into host intestinal cells

3. Recruit actin and strengthen where bacteria has attached

Attach and inject ESPS (E.coli secretion proteins) into host

receptors for attachment protein

pedestal modifies host cytoskeleton (actin)

EHEC, enterohemorrahgic E.coli

colonize large intestine

EHEC, enterohemorrahgic E.coli transmission

consumption of contaminated animal products person-to-person, more in developed countries

EHEC, enterohemorrahgic E.coli complications

colon infection, dysentery

1980s outbreak of hemolytic uremic syndrome (HUS), hemolytic anemia, renal failure, thrombocytopenia

O157:H7

EHEC, enterohemorrahgic E.coli virulence factors

A/E lesions, produces Stx (Shiga toxin)

Stx (shiga toxin)

inhibits protein synthesis in infected cell causes capillary thrombosis and inflammation

circulating of this causes HUS

EHEC, enterohemorrahgic E.coli infecting dose

low, 100 organisms

EAEC, entero-aggregative E.coli

organic fenugreek sprout origin, acquired genes causes shiga toxins (thought it was EHEC)

EHEC, enterohemorrahgic E.coli complications

bloody diarrhea with HUS

EHEC, enterohemorrahgic E.coli 2011 outbreak

novel strain O104:H4 in northern germany