Gastrointestinal infections - bacteriology
•Als PPT, PDF herunterladen•
46 gefällt mir•28,476 views
This is a series of lectures on microbiology, useful for both undergraduate and post graduate medical and paramedical students... This lecture covers cholera, typhoid, diarrhoea and dysentry
Empfohlen
Weitere ähnliche Inhalte
Was ist angesagt?
Was ist angesagt? (20)
Andere mochten auch
Andere mochten auch (20)
Ähnlich wie Gastrointestinal infections - bacteriology
Ähnlich wie Gastrointestinal infections - bacteriology (20)
Mehr von Ashish Jawarkar
Mehr von Ashish Jawarkar (20)
Kürzlich hochgeladen
Kürzlich hochgeladen (20)
Gastrointestinal infections - bacteriology
- 1. Gastrointestinal Infections Dr. Ashish V. Jawarkar, MD (Path)
- 2. Overview • Most infections of the g.i.t. are acquired through contaminated food – food poisoning • Food infection – − Bacteria like - Cholera, E. coli, Salmonella, shigella, − viruses like enterovirus, rotavirus, hepatitis A and E − Parasites like G. lamblia • Food intoxication – S. aureus, B. cereus, Cl. Perfringens, Cl. botulinum
- 3. Symptoms • Abdominal pain • Diarrhoea • Vomitting • Fever
- 4. Factors responsible for spread • Age – children more susceptible • Personal hygiene • Open air defecation • Food at road side stalls • Uncovered food
- 5. Vibrio Cholerae • Vibrio – vibrate – vibratory motility • Present in surface waters worldwide
- 6. • Morphology • Growth characteristics • Biochemical reactions • Resistance • Pathogenicity and virulence • Epidemiology • Diseases caused • Laboratory diagnosis • Treatment
- 7. Morphology • Short, curved comma shaped bacillus • Single polar flagella • Gram negative
- 10. • Morphology • Growth characteristics • Biochemical reactions • Resistance • Pathogenicity and virulence • Epidemiology • Diseases caused • Laboratory diagnosis • Treatment
- 11. Growth characteristics • Aerobic • Colorless colonies on mac conkey • Special media − Transport media − Enrichment media − Plating media
- 12. Transport media • VR medium (Venkatraman, ramkrishnan) • Cary blair medium
- 13. Enrichment media • Alkaline peptone water • Monsur’s taurocholate tellurite peptone water
- 14. Plating media • TCBS medium – thiosulfate, citrate, bile salts and sucrose
- 15. String test • Loopful of colonies mixed with drop of sodium deoxycholate in saline
- 16. • Morphology • Growth characteristics • Biochemical reactions • Resistance • Pathogenicity and virulence • Epidemiology • Diseases caused • Laboratory diagnosis • Treatment
- 17. Biochemical reactions • Cholera red reaction − Ferments glucose, mannitol, maltose, mannose and sucrose − Produces indole which gives red color
- 18. • Morphology • Growth characteristics • Biochemical reactions • Resistance • Pathogenicity and virulence • Epidemiology • Diseases caused • Laboratory diagnosis • Treatment
- 19. Resistance • Resistant to cold – refrigerated food may carry vibrio • Donot survive at room temperature / heating • Susceptible to common drugs like doxycycline
- 20. • Morphology • Growth characteristics • Biochemical reactions • Resistance • Pathogenicity and virulence • Epidemiology • Diseases caused • Laboratory diagnosis • Treatment
- 21. Cholera • Acute diarrhoeal illness • Painless ‘rice water’ stools • Copius vomitting • Fluid loss and dehydration
- 23. • Due to two toxins released by bacteria in intestine • Toxin A and B • Cause pouring of water from body into intestines • Extensive water depletion
- 24. • Morphology • Growth characteristics • Biochemical reactions • Resistance • Pathogenicity and virulence • Epidemiology • Laboratory diagnosis • Treatment
- 25. Epidemiology • Source – infected humans • Mode of transmission – contaminated water/food • Cholera spreads as sporadic/epidemic or pandemic forms • Large movement of people such as during fairs/festivals is associated with cholera spread
- 26. Sporadic • Short duration infection limited to a small area
- 27. Epidemic • Suddenly many cases are seen over a large area
- 28. Pandemic • Cases seen over a long period of time over continents • Till 19th century, cholera was mainly confined to India – mainly area of Ganga plains – Bengal • Total seven pandemics have been identified.
- 29. Seventh pandemic
- 31. • Morphology • Growth characteristics • Biochemical reactions • Resistance • Pathogenicity and virulence • Epidemiology • Laboratory diagnosis • Treatment
- 32. Lab diagnosis • Sample – stool – before administering antibiotics • Use transport medium • Dark field microscopy can be done for darting motility
- 34. • Plated on TCBS medium • Slide agglutination test • String test
- 35. • Morphology • Growth characteristics • Biochemical reactions • Resistance • Pathogenicity and virulence • Epidemiology • Laboratory diagnosis • Treatment
- 36. Treatment • More important is replacement of lost fluid • Antibiotics are of secondary importance • Doxycycline
- 37. Enterobacteria • Flora of large intestine • Classified on basis of growth on Mac Conkey’s medium − Lactose fermenters – E. coli, Klebsiella − Late lactose fermenters – shigella − Non lactose fermenters - Salmonella
- 39. Diarrhoea causing E. Coli ETEC Toxin causes release of water into intestinal lumen Watery diarrhoea EIEC Invade intestinal wall Dysentry Entero invasive E Coli Blood and mucous in stools EHEC Does not invade Bloody diarrhoea Entero hemorrhagic Toxin release Colitis Entero toxicogenic E Coli EPEC Entero pathogenic Infant watery diarrhoea
- 41. • E coli cause − − − − UTI Diarrhoea Pyogenic infections Septicemia • Spread – feco oral route
- 42. Salmonella – Enteric Fever - Typhoid • Also causes gastroenteritis • Motile gram negative rods • Peritrichous flagella
- 43. Salmonella – Enteric Fever - Typhoid • Also causes gastroenteritis • Motile gram negative rods • Peritrichous flagella
- 45. Growth characteristics • Colorless colonies on Mac conkey – Non lactose fermenters • Jet black colonies on Wilson and Blair due to production of H2S
- 46. Growth characteristics • Enrichment media − Selenite F broth − Tetrathionate broth
- 47. Diseases caused • Enteric fever • Gastroenteritis • Septicemia
- 48. Enteric Fever (Typhoid) • Pathogenesis
- 51. Clinical course • Gradual onset with fever, abdominal pain and constipation/diarrhoea • Step ladder fever with bradycardia • Spleen and liver are enarged • Rose spots on skin in second week
- 52. Complications • Intestinal perforation • Hemorrhage • Shock • Cholecystitis • Osteomyelitis
- 53. Epidemiology • Source – food handlers/cooks − Carriers – • Convalescent carriers – shed bacilli for 3 weeks to 3 months after cure • Chronic carriers – more than 3 months after clinical cure
- 54. Typhoid Mary • New york cook – infected more than 200 persons – caused atleast 7 outbreaks
- 55. Lab diagnosis • Cases – Widal test, blood culture • Carriers – isolation from bile
- 56. Widal test
- 58. Blood culture / Bile culture • Take 45ml patient blood in bile broth • Send to lab • Cultured on Mac Conkey • Lactose non fermenting colonies
- 59. Treatment • Chloramphenicol • Ampicillin • Co trimoxazole
- 60. Prophylaxis • Best is improved sanitation • Live oral vaccine – typhoral • Injectable vaccine – typhim vi • Protection lasts 3 years, booster required afterwards
- 61. Shigella – BACILLARY DYSENTRY • DYSENTRY – bacillary (shigella) and amebic (parasitic) • Also caused by EIEC, Campylobacter
- 62. • Gram negative rods • Lactose non fermenters on Mac conkey • Classified according to mannitol fermentation − Sh dysenteriae – mannitol non fermenter − Sh flexneri, sh bodydii and sh sonnei – mannitol fermeters
- 63. Bacillary dysentry • Bacilli infect intestinal epithelial cells • Spread to submucosa • Inflammatory reaction with capillary thrombosis • Sloughing and necrosis of mucosa • Ulcers
Hinweis der Redaktion
- Age; EPEC and rotovirus tend you affect young children Hygiene: fecooral Acidity: protective barrier, low inoculm Motility: expel the pathogens. Antimotility assoc with prolonged fever shedding shigella, complication c diff, HUS in ETEC Flora: ex cdiff