Carbohydrate Metabolism and Enterobacteriaceae Lab 9

These flashcards cover the key terms and concepts related to carbohydrate metabolism and Enterobacteriaceae, as discussed in the lecture notes for the lab.

Enterobacteriaceae

A family of Gram-negative bacteria that includes harmless symbionts and pathogens.

Oxidase negative

Refers to bacteria that do not produce the enzyme oxidase.

Coliform

Rod-shaped, gram-negative bacteria that can ferment lactose, indicating sanitary quality.

Non-coliform

Bacteria that cannot ferment lactose, often pathogenic.

Lactose fermentation

The process by which bacteria convert lactose into acids and gases.

Normal flora

Microorganisms that are typically found in the gut and are usually non-pathogenic.

Gastroenteritis

Inflammation of the stomach and intestines, often leading to vomiting and diarrhea.

E. coli O157:H7

A strain of E. coli that causes hemorrhagic colitis and hemolytic uremic syndrome.

Virulence factors

Molecules produced by pathogens that contribute to their ability to cause disease.

Shiga toxins

Toxins produced by certain E. coli strains that inhibit protein synthesis and can damage human cells.

MRS Agar

Selective medium for Lactobacillus, containing nutrients to promote growth.

Fermentation pathways

Biochemical processes that convert sugars into acids, gases, or alcohol in the absence of oxygen.

Phenol Red Broth

Differential media that indicates acid and gas production during fermentation.

Simmons Citrate

Differential medium used to determine if organisms can utilize citrate as their sole carbon source.

Triple Sugar Iron Agar (TSI)

Medium used to evaluate fermentation patterns and hydrogen sulfide production in bacteria.

pH Indicator

A substance that changes color based on acidity, used in various microbiological media.

MR-VP Broth

Medium used for two tests: Methyl Red (MR) for mixed acid fermentation and Voges-Proskauer (VP) for acetoin production.

Stab and Streak method

A technique used to inoculate bacteria in both deep and surface layers in culture media.

Gas production

The creation of gases during bacterial fermentation, observable in culture tubes.

Acid production

Formation of acid during fermentation, indicated by color changes in pH indicators.

Inoculate

To introduce microorganisms into a culture medium for growth.

Microbes

Microorganisms such as bacteria used in laboratory studies.

Enteric bacteria

Bacteria that are found in the intestines, typically involved in digestion.

Commensals

Bacteria that live harmoniously in the gut without causing harm to the host.

Selective agar

A type of growth media designed to support specific types of bacteria while inhibiting others.

Indicator dyes

Chemical substances that change color under specific conditions to indicate the presence of bacteria.

Lactobacillus

A type of gut bacteria that is generally beneficial and used in fermentation.

Salmonella typhimurium

A pathogenic strain of Salmonella that causes gastroenteritis.

Shigella dysenteriae

A species of Shigella that causes dysentery characterized by severe diarrhea.

Peptone

A soluble protein created by the partial hydrolysis of proteins, used in culture media.

Sugars

Carbohydrates that can be fermented by bacteria to produce energy.

Carbohydrate metabolism

The biochemical process through which organisms convert sugars into energy.

Microbial flora

The community of microorganisms present in a specific environment, such as the gut.

Nosocomial infections

Infections acquired in a hospital or healthcare facility.

Differential fermentation

The ability to ferment different types of carbohydrates resulting in various end products.

Chromosomal mutation

A change in the DNA sequence of a bacterium that can affect its traits.

Fermentation test

A test performed to evaluate the ability of bacteria to ferment specific carbohydrates.

SA Plate (Sodium acetate)

A selective agent used in some growth media to inhibit certain bacteria.

Polysorbate 80

A surfactant used to facilitate nutrient uptake in selective media.

Black/metallic green color

A typical result indicating strong lactose fermentation on EMB agar.

Alkaline by-products

Products formed during the degradation of amino acids that raise the pH.

Glucose fermentation

The process by which bacteria convert glucose into acids and gases.

Aerotolerance

The ability of microorganisms to survive in the presence or absence of oxygen.

Enterics

A group of Gram-negative bacteria, primarily found in the intestines of humans and animals, which includes important pathogens as well as commensals.