Shigella

Views:
 
Category: Entertainment
     
 

Presentation Description

No description available.

Comments

Presentation Transcript

Book Antiqua:

1 Shigella Dr.Gogoi;University of Fiji

Wingdings:

2 Shigella Belong to Enterobacteriaceae Non motile , non capsulated NLF on MAC Deoxycholate citrate agar (DCA) selective media (pale color colonies) Gram negative bacilli

Times New Roman:

3 Shigella species Mannitol Non Fermentation Fermentation S dysentriae -12 S flexneri- 6 S boydii - 18 S sonnei (Late lactose fermenter)

Arial Black:

4 Epidemiology and Clinical Syndromes Major cause of bacillary dysentery Outbreaks in daycare centers, nurseries, institutions Estimated 15% of pediatric diarrhea in U.S. Leading cause of infant diarrhea & mortality in developing countries Epidemics of S. dysenteriae type 1 have occurred in Africa and Central America with case fatality rates of 5-15%. Common in P ediatric age group (1-10 yrs) Developed world – S sonnei , developing world – S flexneri

Hardcover:

5 Epidemiology and Clinical Syndromes Shigellosis = Generic term for disease Low infectious dose (10 2 -10 4 CFU) Humans are only reservoir Transmission by fecal-oral route Incubation period = 1-3 days Watery diarrhea with fever; changing to dysentery Bacillary Dysentry Passing blood & mucus in the stool

Bitmap Image:

6 Infection cycle of Shigella Shiga toxin exacerbate inflammation by causing ishchemia & hemorrhage Ulcers Rarely lead to bacteremia Organisms adhere to colonic lymphoid follicles Undergo parasite directed phagocytosis Resist intracelluar killing Move directly from cell to cell SMALL GUT LARGE GUT STOMACH

Shigella:

7 Pathogenesis Two-stage disease Early stage Second stage Fever attributed to neurotoxic activity of toxin D ysentery due to a dherence and tissue invasion of large intestine ( c ytotoxic activity of Shiga toxin ) Watery diarrhea attributed to the enterotoxi n activity of Shiga toxin in the small intestine Enterotoxic , neurotoxic and cytotoxic Shiga toxin Similar to Shiga-like toxin of E nterohemorrhagic E. coli (EHEC)

Shigella:

8 Virulence factors Invasiveness Attachment (adherence) and internalization with complex genetic control Large multi-gene virulence plasmid regulated by multiple chromosomal genes Intracellular survival & multiplication Exotoxin (Shiga toxin) Complications : Hemolytic uremic syndrome and reiters syndrome

Shigella species:

9 Clinical manifestation Fever Abdominal cramping & tenderness Diarrhea / Dysentry Tenesmus (straining at stools Sigmoidoscopy: ulceration

PowerPoint Presentation:

8/11/2013 10 Lab Diagnosis of Dysentry Specimens Stool, rectal swab from an ulcer ( buffered glycerol saline - transport medium) Culture MAC NLF colonies AST Report & Interpretations TSI agar K - / A - DCA NLF

PowerPoint Presentation:

11 Shigella Dysentry- Differentiated from Dysentry like diseases Entero invasive E coli Campylobacter jejuni Entamoeba histolytica Balantidium coli

PowerPoint Presentation:

12 Treatment For adults No vaccines Rehydration if necessary For children Co-trimoxazole or ampicillin + rehydration Norfloxacin or ciprofloxacin Water supply Sewage maintenance Human carriers identified & treated Breast feeding than formulas Prevention

PowerPoint Presentation:

13 Summary Bacillary Dysentry Clinical manifestation Species of Shigella Pathogenesis Virulence factors Source and spread Laboratory diagnosis Antibiotics used Preventive measures