Escherichia Coli ppt for nursing students

it will be helpful for nursing students

1. ESCHERICHIA COLI

2. Introduction: Escherichia coli was isolated in 1885 from a fecal sample of an infant. It is normal inhabitant of human intestine and is shed in feces . It may contaminate the water or food products and transmit the infection to healthy people.

3. Morphology: It is gram negative bacillus The organism is non capsulated. Most of the strains are motile due to presence of flagella. Size is 1-3 x 0.4-0.7 µm

4. Cultural Characteristics/ Growth features: These are aerobes and facultative anaerobes These can grow on ordinary nutrient medium at 37 C after overnight incubation. The colonies are circular, smooth and colourless On McConkey agar, pink colonies are produced because of lactose fermentation. The growth of E. coli is inhibited by salt containing media. Some strains produce β haemolysis on blood agar.

5. Cultural Characteristics/ Growth features: The organism can survive for many days on clothing in soil, air, water and dust. Moist heat kills it at temperature of 60 C for 30 minutes Chlorine can kill it in water

6. Pathogenicity: By means of ingestion of contaminated food, organism first reaches to stomach through which it enters into intestine. In intestine it attached on intestinal epithelial cells with the help of fimbria which helps in multiplication of bacteria and colonization, as a result it releases enterotoxins thereby developed symptoms

7. Pathogenicity: E. coli is responsible for four different types of clinical infections. Diarrhoea and dysentery Urinary tract infections Pyogenic infections Septicaemia Childrens are more prone to this infection.

8. Lab Diagnosis Samples are collected from urine, faeces, pus, blood and CSF The sample from midstream urine is inoculated on McConkey agar or blood agar plate. The plates are inoculated at 37 C for overnight and colonies are formed Gram staining confirms morphology and gram negativity Biochemical tests are performed which shows Indole and Methyl Red (MR) positive, VP and citrate tests are negative The organism shows agglutination with specific antiserum which confirms the identity of organism

9. Treatment The infection is treated with antibiotics like penicillin or cephalosporins, trimethoprim, tetracycline Oral rehydration therapy is given to the patient

10. Prevention The disease could be prevented by increasing fluid intake. Proper hand washing

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