Enterobacteriaceae Identification Quiz

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Questions and Answers

Match the following bacteria with their fermentation type:

Escherichia = Lactose Fermenter Shigella = Non-Lactose Fermenter Klebsiella = Lactose Fermenter Salmonella = Non-Lactose Fermenter

Match the following agar types with their characteristics:

EMB Agar = Selective and differential XLD Agar = Detects hydrogen sulfide (H2S) Hektoen Enteric Agar = Targets Salmonella/Shigella SS Agar = Inhibits gram-positive organisms

Match the following non-lactose fermenters with their characteristics:

Salmonella = Produces H2S and black center Shigella = Does not produce H2S Proteus = Non-Lactose Fermenter Yersinia = Non-Lactose Fermenter

Match the following lactose fermenters with their appearance on XLD agar:

Escherichia coli = Yellow colonies Citrobacter = Yellow colonies Serratia = Red colonies with black centers Klebsiella = Yellow colonies Signup and view all the answers

Match the following fermentation results with the media type:

Orange color = Indicates lactose fermentation (HE agar) Blue green color = Indicates Shigella (HE agar) Yellow colonies = Indicates nonpathogens (XLD agar) Colorless colonies = Indicates Shigella (XLD agar) Signup and view all the answers

Match the following carbohydrates found in XLD agar:

Sucrose = In excess to detect fermentation Lactose = In excess to detect fermentation Xylose = Present to detect hydrogen sulfide production Lysine = Used for decarboxylation detection Signup and view all the answers

Match the following colors with their meaning in Hektoen Enteric Agar:

Orange = Low pH from lactose fermentation Blue green = Indicates target pathogen (Shigella) Black center = Indicates H2S production (Salmonella) Yellow = Indicates lactose fermentation Signup and view all the answers

Match the following Enterobacteriaceae species with their classification:

Escherichia coli = Opportunistic pathogen Salmonella spp. = Primary pathogen Klebsiella pneumonia = Opportunistic pathogen Shigella spp. = Primary pathogen Signup and view all the answers

Match the following late lactose fermenters with their initial characteristics:

Serratia = Initially Non-Lactose Fermenter Enterobacter = Initially Non-Lactose Fermenter Citrobacter = Initially Non-Lactose Fermenter (LLF) Proteus = Non-Lactose Fermenter Signup and view all the answers

Match the following characteristics with the correct type of bacteria:

All ferment glucose = Enterobacteriaceae Oxidase negative = Enterobacteriaceae Not very useful in identification = Cellular morphology Facultatively anaerobic = Enterobacteriaceae Signup and view all the answers

Match the following infections with the corresponding Enterobacteriaceae species:

Septicemia = Escherichia coli Urinary tract infections = Klebsiella pneumonia Meningitis = Escherichia coli Gastroenteritis = Salmonella spp. Signup and view all the answers

Match the following media with their use in Enterobacteriaceae identification:

MacConkey Agar = Selective and differential BAP = Macroscopic morphology Crystal violet = Inhibits gram-positive growth Bile salts = Inhibits gram-positive growth Signup and view all the answers

Match the following tests with their characteristics in Enterobacteriaceae:

Nitrate reduction = All reduce nitrate to nitrites Motility test = All motile at body temperature except... Glucose fermentation = All ferment glucose Oxidase test = All are oxidase negative Signup and view all the answers

Match the following terms with their descriptions:

Opportunistic pathogens = Normal flora causing infections in non-normal sites Primary pathogens = Always pathogens Normal flora = Part of the gut microbiome Infections = Result from pathogenic species Signup and view all the answers

Match the following features with the Enterobacteriaceae species:

Mucoid colonies = Klebsiella pneumonia Large gray colonies = Enterobacteriaceae on BAP Pathogenic E. coli = Shigella spp. Non-motility = Klebsiella Signup and view all the answers

Match the following terms with their key characteristics:

Facultatively anaerobic = Can grow with or without oxygen Gram-negative = Identified via Gram staining Coccobacilli = Cellular morphology type Selective plates = Used for pathogenic species identification Signup and view all the answers

Match the following bacterial tests with their primary purpose:

Lactose Utilization Test = Differentiate lactose fermenting from non-lactose fermenting species ONPG Test = Determine if a dLF is a true NLF Glucose Fermentation Test = Test for acid production from glucose O/F Test = Assess aerobic vs anaerobic carbohydrate utilization Signup and view all the answers

Match the bacterial enzymes with their functions:

β-galactoside permease = Transports lactose into the cell β-galactosidase = Breaks down lactose into glucose and galactose Acid production = Indicates glucose fermentation pH indicators = Detects acid presence in media Signup and view all the answers

Match the terms with their definitions:

Lactose = Disaccharide made of glucose and galactose dLF = Bacteria that lack β-galactoside permease NLF = Non-lactose fermenting bacteria Yellow color in ONPG test = Indicates positive result for β-galactosidase activity Signup and view all the answers

Match the test conditions with their results:

Positive ONPG result = Yellow color Negative ONPG result = Clear Lactose Utilization Positive = Lactose fermentation observed Glucose Fermentation = Acids detected by pH indicators Signup and view all the answers

Match the media usage with their testing purpose:

Sterile saline = First step in performing ONPG test Bacterial suspension = Required for ONPG testing High sugar content in OF test = To observe oxidation ability pH indicator media = Used to detect acid from fermentation Signup and view all the answers

Match the products of glucose metabolism pathways:

Glycolysis = Produces pyruvate from glucose Fermentation = Yields strong acids Oxidation = Produces weak acids Anaerobic pathways = Do not require oxygen Signup and view all the answers

Match the characteristics with their respective metabolic pathways:

Oxidation = Aerobic carbohydrate utilization Fermentation = Anaerobic carbohydrate utilization Lactose fermentation = Metabolizes lactose into acids Glucose utilization = Can lead to acid and gas production Signup and view all the answers

Match the enzyme-related features with their corresponding information:

β-galactoside permease = Allows entry of lactose into bacterial cells β-galactosidase = Species that ferment lactose can produce ONPG = Substrate to test for β-galactosidase False-positive potential = Yellow pigment producing bacteria in ONPG test Signup and view all the answers

Match the following compounds with their associated reactions or results:

Butylene glycol = Produces diacetyl Diacetyl + KOH = Red complex formation Citrulline = Converted to putrescine Cadaverine = Product of lysine decarboxylation Signup and view all the answers

Match the following amino acids with their corresponding decarboxylase enzymes:

Lysine = Lysine decarboxylase Ornithine = Ornithine decarboxylase Arginine = Arginine dihydrolase Citrulline = Not applicable in the test Signup and view all the answers

Match the following tests with their specific purposes:

Decarboxylase test = Differentiate Enterobacterales Dihydrolase test = Identify arginine conversion Phenylalanine deaminase test = Oxidatively deaminate phenylalanine Moeller’s broth medium = Detect decarboxylation Signup and view all the answers

Match the following results with their corresponding color changes:

Positive decarboxylation = Purple color Negative decarboxylation = Yellow color Phenylpyruvic acid reaction = Green complex with ferric chloride Un-inoculated media = Yellow color at pH 6.0 Signup and view all the answers

Match the following bacteria genera with their ability to produce specific enzymes:

Morganella = Positive for phenylalanine deaminase Proteus = Positive for phenylalanine deaminase Providencia = Positive for phenylalanine deaminase E. coli = Negative for phenylalanine deaminase Signup and view all the answers

Match the following components of Moeller’s broth with their functions:

Glucose = Provides fermentable sugar Peptones = Nutrient source Bromocresol purple = pH indicator Oil overlay = Creates anaerobic environment Signup and view all the answers

Match the following conditions necessary for decarboxylation with their descriptions:

Acid pH = Initial condition for decarboxylation Anaerobic environment = Created by oil overlay Control tube = Used for comparison Alkaline pH shift = Indicates positive result Signup and view all the answers

Match the following products with their respective sources in the deamination test:

Phenylpyruvic acid = From phenylalanine deamination Ammonia = Byproduct of deaminating phenylalanine Putrescine = From ornithine conversion Citrulline = Intermediate in arginine metabolism Signup and view all the answers

Match the following tests with what they detect or indicate:

Methyl red test = Mixed acids from glucose metabolism Voges-Proskauer test = Acetoin production Citrate test = Citrate utilization Indole test = Indole production from tryptophan Signup and view all the answers

Match the carbohydrate fermentation results with their corresponding descriptions:

Glucose only = Acid slant and acid butt on TSI agar Glucose and lactose or sucrose = Ferments multiple carbohydrates Lactose only = Does not ferment glucose Lactose and sucrose = Does not ferment glucose Signup and view all the answers

Match the metabolic products with the tests where they are detected:

Mixed acids = Detected by Methyl red test H2S = Detected in sulfide production test Phenylpyruvate = Found in phenylalanine deaminase test Indole = Produced from tryptophan in Kovac’s reagent Signup and view all the answers

Match the characteristics of indole-positive bacteria:

Produce tryptophanase = Indicates indole production capability Deaminate lysine = Not associated with indole production Decarboxylate tryptophan = Not related to indole Decarboxylate ornithine = Not related to indole Signup and view all the answers

Match the colony colors on various agar media with the organisms they indicate:

Black colonies on XLD = Salmonella Orange colonies on HEK = Shigella Pink colonies on SS agar = E.coli Non-pathogenic Enterobacteriaceae = Indicated by specific agar colors Signup and view all the answers

Match the following tests with their results:

Tryptophan Deaminase Test = Reddish brown positive Citrate Utilization Test = Blue positive Indole Test (Kovac's reagent) = Red positive MIO Agar (Positive Motility) = Clouding of medium Signup and view all the answers

Match the following tests with their purposes:

Tryptophan Deaminase Test = Determine ability to oxidatively deaminate tryptophan Citrate Utilization Test = Determine use of sodium citrate as a carbon source Indole Test = Identify organisms producing tryptophanase MIO Agar = Detect motility and decarboxylase production Signup and view all the answers

Match the following positive results with their corresponding tests:

Citrate Utilization = Blue Indole with Ehrlich's reagent = Red Tryptophan Deaminase Test = Reddish brown MIO Agar Ornithine Decarboxylation = Purple throughout medium Signup and view all the answers

Match the following negative results with their respective tests:

Citrate Utilization = Green Indole Test = Light brown Tryptophan Deaminase Test = Colorless MIO Agar Motility = No clouding of medium Signup and view all the answers

Match the following tests with the correct reagents used:

Indole Test (Spot Method) = DMACA reagent Indole Test (Kovac's reagent) = Kovac's reagent Indole Test (Ehrlich's reagent) = Ehrlich’s reagent MIO Agar = Kovac’s reagent for indole detection Signup and view all the answers

Match the following microorganisms with their positive tests:

E. coli = Tryptophan Deaminase Test positive P. vulgaris = Tryptophan Deaminase Test positive Klebsiella spp. = MIO Agar with positive motility Enterobacter = Differentiated by MIO Agar Signup and view all the answers

Match the following limitations with their respective tests:

Citrate Utilization Test = Some organisms grow without color change Tryptophan Deaminase Test = Light brown can be confusing Indole Test = Result varies with reagent used MIO Agar = Semi-solid medium may complicate reading Signup and view all the answers

Match the following outcomes with their definitions:

Positive result = Indicates the specific enzyme is present Negative result = Indicates the specific enzyme is absent Color change = Reveals chemical activity of organisms No growth = Organisms unable to utilize the substrate Signup and view all the answers

Study Notes

Overview of Enterobacteriaceae Identification Methods

Lecture 9 covers identifying Enterobacteriaceae
Includes information from Bailey & Scott's (Chapter 12, 19) and Diagnostic Microbiology (Chapter 9, 19)
Lecture introduces Enterobacteriaceae, common identification methods, special media and test systems.