Bacterial Diversity and Major Bacterial Phyla

Vocabulary flashcards covering bacterial diversity, classification, and key pathogenic and environmental species from the lecture notes.

Bacillota (Firmicutes)

• A phylum of Gram-positive bacteria characterized by

• thick cell walls containing several layers of peptidoglycan supported by teichoic acids

• thick walls resist drying

• a low G+C content.

• include Bacilliota that produce spores

Actinomycetota (Actinobacteria)

• A phylum of Gram-positive bacteria

• peptidoglycan w/ a thick waxy lipid coat containing mycolic acids

• high G+C content

• acid-fast staining properties.

Mycoplasmatota

A phylum containing the smallest and simplest self-replicating bacteria that evolved from Bacillota

• characteristically lack peptidoglycan cell walls.

Pseudomonadota (Proteobacteria)

A highly diverse phylum of Gram-negative bacteria capable of a wide range of metabolic lifestyles.

Bacteroidota (Bacteroidetes)

A phylum of Gram-negative rod-shaped bacteria, the majority of which are obligate anaerobes.

Spirochaetota

A phylum of bacteria with a distinctive form consisting of tightly coiled cells enclosed by an outer sheath, with periplasmic flagella running underneath the sheath.

Cyanobacteriota

Oxygenic photosynthetic bacteria ranging from tiny marine organisms to massive filamentous forms; the only bacterial phylum that produces oxygen.

Chlamydiota

A phylum of obligate intracellular pathogenic bacteria that replicate as inclusion bodies within host cells.

Endospores

Inert, heat-resistant survival structures formed by certain Bacillota that resist drying, freezing, and chemical disinfectants and can remain viable for thousands of years.

Endospore structure layers

Concentric defensive layers protecting the bacterial core, consisting of the inner membrane, germ cell wall, cortex, outer membrane, and spore coat.

Bacillus anthracis

A Gram-positive, rod-shaped, endospore-forming soil bacterium belonging to Bacillota that causes anthrax.

Clostridioides difficile

An endospore-forming rod with bulging spores that causes severe intestinal disease when normal microbiota are reduced by antibiotic treatment.

Clostridium

A genus of obligate anaerobic,

• endospore-forming rods whose developing spores swell the cell into a club shape;

• includes the agents of tetanus (C. tetani) and botulism (C. botulinum)

Lactococcus and Lactobacillus

• Gram-positive, nonendospore-forming bacilli

• ferment milk to make yogurt and cheese

Staphylococcus aureus

A Gram-positive non-spore-forming coccus that infects the skin and can cause toxic shock syndrome and methicillin-resistant S. aureus (MRSA) infections.

Mycoplasmatota

A cell wall-less, pleomorphic ameboid bacterium that produces characteristic 'fried-egg' colonies on agar and causes atypical pneumonia.

Actinomycetes

• (a major class of Actinomycetota)

• Form mycelia with branching filaments

Mycobacterium tuberculosis

An acid-fast, facultative intracellular short rod with an exceptionally thick, lipid-rich cell wall that is transmitted via respiratory droplets and causes tuberculosis.

Listeria

intracellular pathogens causing diseases affecting the GI tract and nervous system

Grow at refrigerator temperature

actinomyces israelli

forms branched mycelial filaments

causes actinomycosis

Cutibacterium acnes/ Propinibacterium acnes

Short rod; causes acne

Propionibacterium freudenreichii

Rod; makes Swiss Cheese