Strain Pathogenic Mechanism Enteric Infection(s) Common Clinical Presentation

ETEC LT and ST Diarrhea; Traveler's Profuse watery diarrhea, cramps,

diarrhea Nausea, dehydration

EPEC Adherence factor; Accute diarrhea Watery diarrhea, fever, vomiting,

Attachment to and affacement mucus in stool

of intestinal epithelium

EIEC Invasion and destruction of Dysentry similar to Dysentry; scant stool; blood, mucus

intestinal mucosa epithelium Shigella dysenthry

and leucocytes in stoo; fever; cramp

EHEC Shiga-lika toxinDiarrhea; haemorrhagic

Diarrhea (no leucocytes); abdominal

colitis cramp; blood in stool; fever, HUS

may or may not be present

EAggEC Unknown Chronic and acute Watery diarrhea, vomiting

diarrhea

1. Escherichia coli Labor. Diagnosis; Treatment and Prevention

Epidemiology and Laboratorium diagnosis of Pathogenic E.coli - fig. 6

Treatment : Specific antibacterial therapy is not indicated; fluid replacement may be necessary, especially in young children; For HUS is urgent and may involve dialysis

Prevention : Provision of a pure water and adequate system for sewage disposal are fundamental.

Food and unpasteurized milk may be important vehicle of infection, especially for EIEC and EHEC

2. Salmonella PathogenesisAll Salmonella except S.typhi and S.paratyphi are found in animal as well as human. There is a large animal reservoir of infection which is transmitted to man via contaminated food. Waterborne infection is less frequent

Pathogenesis of Salmonella diarrhoea : diarrhoea is produce as a result of invasion by the salmonella of epithelial cells in the terminal portion of the small intestine

The bacteria migrate to the lamina propria layer of the ileocaecal region multiplication stimulates an inflamation response infection to GIT mediate the release of prostaglandins in turn activate cyclic AMP and fluid secretion diarrhoea

2. Salmonella Clinical features and laboratorium diagnosis

Salmonella cause an acute but self-liiting diarrhoea, but in the young and elderly symptoms may be more severe. Incubation 6 hours – 2 days

Duration 3 days-3 weeks. Vomiting is rare and fever is usually a sign of invasive disease

Diarrhoea caused by salmonella cannot distinguish from other causes without culturing faecal specimens on selective media

Preliminary identification without culturing faecal specimens on selective media can be made rapidly but, complete result, including serotype 48 hours

2. Salmonella Treatment Diarrhoea is usually self-limiting and

resolves without treatment

Fluid and electrolyte replacement msy be required particularly in the very young and the elderly

Unless there is evidence of invasion and septicemia, antibiotic positivelydiscouraged because they do not reduce the symptom or shorten the illness, and may prolong excretion of salmonellaa in the faeces.

There is some evidence that symptomatic treatment with drugs that reduce diarrhoea has the same adverse effect.

2. Salmonella Prevention Prevention : breaking the chain between

animal and human, and between human; clean drinking water; proper sewage disposal; and education programmes on hygienic food preparation

Following an episode of salmonellae diarrhoea, people may continue to carry and excrete organism in their feaces for several weeks

Although in the absence of the symptom the m.o. will not be disperse so liberally into the environment, proper hand washing prior to handling is essential

Person who food handler are not work until 3 specimen of faeces have failed to grow salmonellae

To be continued