Enterobacteriaceae

• Enterobacteriaceae - Gram-Negative Non-sporeforming
• Enterobacteriaceae - Small gram-negative rods (2-5 x 0.5 microns), which contains lipopolysaccharides in their cell envelope.
• Most motile with peritrichous flagella • Shigella and Klebsiella are nonmotile
• Some strains true pathogens • Salmonella, Shigella, Yersinia, some strains of E. col
• Enterobacteriaceae - All ferment glucose and are oxidase negative.
• Non–lactose-fermenting genera may be more pathogenic.
• True or False. True -All are facultative anaerobes, permitting survival in the gastrointestinal (GI) tract
• COMMON SEROLOGICAL PROPERTIES: O antigen K antigen H antigen
• O antigen polysaccharide portion of LPS
• K antigen capsular antigen
• H antigen - flagellar antigen
• Endotoxin, Exotoxins, Adhesins and fimbria, Intracellular growth, Antibiotic resistance, Capsule - Give the virulence factors of enterobacteriaceae
• Exotoxins - produced by some species and strains, cause diarrhea
• Endotoxin - a part of the LPS produced by all Enterobacteriaceae, is responsible for many of the systemic manifestations of infection.
• Adhesins and fimbria - on some species promote adhesion to the colon, bladder, or other tissues
• Intracellular growth - (Shigella, Salmonella and Yersinia species and Enteroinvasive Escherichia coli) protects organisms from host defenses
• Antibiotic resistance - develops rapidly and often is encoded on plasmids, which can be transferred to related bacteria.
• Capsule - on Klebsiella and Salmonella species is antiphagocytic
• LACTOSE FERMENTER, LACTOSE NON-FERMENTERS, LACTOSE VARIABLE - CLASSIFICATION BASED ON LACTOSE FERMENTATION
• most Escherichia coli usually Klebsiella - WHAT ARE THE LACTOSE FERMENTERS
• Edwardsiella, Salmonella, Shigella, Serratia, Proteus, Providencia, Yersinia - what are the LACTOSE NON-FERMENTERS
• Arizona, Citrobacter, Enterobacter - What are those LACTOSE VARIABLE
• ENRICHMENT LIQUID MEDIA - Extends LAG PHASE of normal flora and decreases LAG PHASE of pathogens
• GN broth - best for Shigella
• BLOOD AGAR - agar used in screening media
• SCREENING MEDIA - Used primarily for Enteropathogenic E. coli for it may not grow on selective medi
• DIFFERENTIAL MEDIA - It differentiates lactose fermenters from lactose non lactose fermenters
• pH indicator, sugar, inhibitor of gram-positive organisms - What are the compositions of Differential Media
• Eosin Y + Methylene Blue - what is the indicator of Eosin Methylene Blue agar
• Neutral red - what is the indicator of MacConkey Agar for lactose fermentation
• Sodium Citrate - It inhibits Coliforms and Proteus
• Bile Salts and Crystal Violet - it inhibits gram positive organisms in MacConkey Agar
• EOSIN Y + METHYLENE BLUE - it inhibits gram positive organisms in Eosin Methylene Blue Agar
• Lactose + Sucrose - What are the sugars in Holt Harris in Eosin Methylene Blue Agar
• Lactose - what is the sugar in Levin in Eosin Methylene Blue Agar
• Lactose - What is the sugar content of MacConkey Agar
• Black purple, may have metalic sheen - What is the color of Fermenters in Holt-Harris
• Colorless - What is the color if non fermenters in Holt-Harris
• Proteus vulgaris, Serratia - It appears as lactose fermenters in Holt-Harris for they ferment sucrose
• Proteus vulgaris and Serratia appears colorless for it will not ferment lactose