Medical Bacteriology - Escherichia coli-E. Coli

Medical Bacteriology

1. VIVEKANANDHA ARTS AND SCIENCE COLLEGE FOR WOMEN Veerachipalayam, sankagiri, salem, Tamilnadu DEPARTMENT OF MICROBIOLOGY SUBJECT : MEDICAL BACTERIOLOGY TOPIC: ESCHERICHIA COLI SUBJECT INCHARGE: SUBMITTED BY : Dr. R. MYTHILI RAVICHANDRAN S. SUBA Head of the Department, lll- BSC Microbiology Department of Microbiology, Department of Microbiology Viaas, sankari. Viaas, Sankari

2. 𝙴𝚂𝙲𝙷𝙴𝚁𝙸𝙲𝙷𝙸𝙰 𝙲𝙾𝙻𝙸 𝕊 . 𝕊𝕌𝔹𝔸

3. 🅒︎🅞︎🅝︎🅣︎🅔︎🅝︎🅣︎🅢︎ Introduction Morphology Culture Pthogenecity Virulence Factors of E. Coli Pathogenesis Laboratory Diagnosis

4. Biochemical test Treatment and preventive Measures Vaccination and preventive Measures

5. 𝕀𝕟𝕥𝕣𝕠𝕕𝕦𝕔𝕥𝕚𝕠𝕟 It was first described by Theodor Escherich in 1885 E. Coli is the most important species encountered as human pathogen It is also the most common aerobe to be harbored in the gut of humans and animals After excreted in feces, it remains Viable only for some days in die environment Other species are less important as human pathogens. These include E. Hermannii and E. Vulneris which are rarely isolated from clinical specimens

6. 𝚃𝚑𝚎𝚘𝚍𝚘𝚛 Escherich

7. 𝕄𝕠𝕣𝕡𝕙𝕠𝕝𝕠𝕘𝕪 Shape: Rod shaped, Bacillus Size: 1-3×0.4-0.7mm in size Colony characteristics: On Nutrient agar- it produces large, circular, low convex, white moist, opaque and smooth colonies On Macconkey agar - it produces bright pink colonies due to the lactose fermentation On Blood agar – it produces beta hemolytic colonies

8. It motile by peritrichous flagellae , through some strains are non- motile Spores are not formed. Capsules and fimbriae are not are found in some strains

9. ℂ𝕦𝕝𝕥𝕦𝕣𝕖 Grows at temperature range of 10-40°(optimum 37°)and pH 7.2 Grows on a wide range of media including Muller – Hinton agar, Nutrient agar, Blood agar. Nutrient agar: it produce large , circular, low convex, grayish white, moist, opaque and smooth colonies Macconkey agar- it produces bright pink colonies due to the lactose fermentation On Blood agar : it produces beta hemolytic colonies Liquid broth culture- it produces beta turbid growth

10. ℙ𝕒𝕥𝕙𝕠𝕘𝕖𝕟𝕚𝕔𝕚𝕥𝕪 Disease Transmission Escherichia coli infections are mainly transmitted by ingestion of contaminated food and water Incubation period 3 to 4 Days

11. 𝕍𝕚𝕣𝕦𝕝𝕖𝕟𝕔𝕖 𝕗𝕒𝕔𝕥𝕠𝕣𝕤 𝕠𝕗 𝔼. ℂ𝕠𝕝𝕚 Adhesins a)Colonization Factor Antigen(CFA I, CFA II, CFA III) b)Type 1 Fimbriae c)P Fimbriae d)S Fimbriae e)Intimin ( Non- fimbrial adhesin) f)EPEC Adherence factor

12. Invasins a)Hemolysin b)Shigella- like “invasins” for intracellular invasion and spread Motility / Chemotoxis a)Flagella Toxins a)Heat labile toxin b)Heat stable toxin c)Shiga toxin d)Cytotoxin e)Endotoxin

13. Antiphagocytic surface properties a)Capsules b)K-Antigens c)Lipopolysaccharides (LPS) Defence against immune responses a)K-Antigens b)Lipopolysaccharides (LPS) c)Capsules Defence against serum bacterial reactions a)K-Antigens b)Lipopolysaccharides (LPS)

14. ℙ𝕒𝕥𝕙𝕠𝕘𝕖𝕟𝕚𝕤 𝕠𝕗 𝔼. ℂ𝕠𝕝𝕚 Escherichia coli bacteria normally live in the intestine of people and animals Most Escherichia coli are harmless and actually are an important part of a healthy human intestinal tract. However, some E. Coli are pathogenic ( they can cause illness), either diarrhea or illness outside of the intestinal tract

15. Pathogenic Strains of E. Coli are responsible for three types of infection’s in humans: 1)Urinary tract infections(UTI) 2)Neonatal meningitis, and 3)Intestinal diseases(Gastroenteritis ) The disease caused (or not caused )by a particular strain of Escherichia coli depend on distribution and expression of an array of virulence determinants, including Athesinns, invasins, toxins and abilities to withstand host defenses.

16. 𝕃𝕒𝕓𝕠𝕣𝕒𝕥𝕠𝕣𝕪 𝔻𝕚𝕒𝕘𝕟𝕠𝕤𝕚𝕤 𝕠𝕗 𝔼. ℂ𝕠𝕝𝕚 MICROSCOPIC EXAMINATION Gram staining - pink colured gram negative rods Motility test – Motile COLONY MORPHOLOGY ON CULTURE MEDIUM Nutrient agar – colonies are large, thick, greyish whitr , moist, smooth, opaque or translucent. Macconkey agar – pink colured lactose fermenting colonies. Eosin methylen blue(EMB) – selective medium for e. Coli. In EMB agar e.Coli Shows metallic sheen production. Salmonella shigella agar (SSA) – pink colonies are produced

17. 𝔹𝕚𝕠𝕔𝕙𝕖𝕞𝕚𝕔𝕒𝕝 𝕋𝕖𝕤𝕥𝕤 Catalase test-positive Oxidase test- Negative Urease test- Negative Indole test – Positive Methyl Red (MR) test- positive Voges Proskauer (VP) test- Negative Citrate Utilization test- Negative TSI test- Acid butt, Acid slant and Gas production observed

18. 𝕋𝕣𝕖𝕒𝕥𝕞𝕖𝕟𝕥 𝕒𝕟𝕕 ℙ𝕣𝕖𝕧𝕖𝕟𝕥𝕚𝕧𝕖 𝕄𝕖𝕤𝕦𝕣𝕖𝕤 Antibiotic Therapy Enteric pathogens are treated sytomatically unless disseminated disease occurs Antibiotic Therapy is guided by invitro susceptibility test Escherichia coli Sometimes leads to pneumonia and it requires a)Respiratory support b)Adequate oxygenation c)Antibiotics, such as Third Generation Cephalosporins or Fluoroquinolones

19. 𝕍𝕒𝕔𝕔𝕚𝕟𝕒𝕥𝕚𝕠𝕟 𝕒𝕟𝕕 ℙ𝕣𝕖𝕧𝕖𝕟𝕥𝕚𝕧𝕖 𝕄𝕖𝕒𝕤𝕦𝕣𝕖𝕤 Appropriate infection –control practices are used to reduce the risk of nosocominal infections ( e. G., restricting use of antibiotics, avoiding unnecessary use of urinary tract catheters) Maintenance of high hygienic strands to reduce the risk of exposure to gastroenteritis strain. Proper cooking of beef products to reduce risk of Escherichia coli infections

20. 𝓣𝓱𝓪𝓷𝓴 𝔂𝓸𝓾...