Bacteriology I

cocci shape

ball-like structure

rod shape

oval

cocci stain color

purple (thick peptidoglycan layer)

rod stain color

purple (thick peptidoglycan layer)

mycobacterium stain color

resists staining (acid fast: not truly positive or negative)

cocci genus

Staphylococcus

Streptococcus

Enterococcus

Staphylococcus Species

S. aureus

S. epidermis

S. saprophyticus

S. lungdunensis

S. haemolyticus

Streptococcus Species

S. progenies (Strep A)

S. algalactiae (Strep B)

S. pneumonia

Rod Genus

Bacillus

Listeria

Corynebacterium

Clostridium

Bacillus Species

B. anthraces (Anthrax)

B. cereus

Corynebacterium Species

C. diphtheriae (Diphtheria)

Clostridium Species

C. difficile

C. perfinges

C. tetani (Tetanus)
C. botulinum

Mycobacterium Species

Tuberculosis

Staphylococcus epidemiology

found in normal flora

-bad if it gets in wrong location

Staphylococcus transmission

person to person

fomite

disruption of normal flora

Staphylococcus virulence factors

capsule: sugar cell complicates phagocytosis

adhesin: molecule on bacterial cell that allows it to bind to a host cell

biofilm: slimy film that protects bacteria from antibiotics and the environment

toxins

-cytotoxins: shrink cell and allow bacteria to get through

-enterotoxin (A-B toxin): enter the cell and interfere with functions

-superantigen: creates a strong, damaging immune response

enzymes: breaks down cells and tissues

drug resistance: MRSA

-super bug: resistant type of Staph that is difficult to treat

Staphylococcus disease

bullous impetigo: staph under the skin

scalded skin syndrome: enzymes break down tissue

bacteremia: bacteria in bloodstream

Staphylococcus treatment

antibiotics

-can be resistant

Staphylococcus prevention

clean/sterilize medical equipment

minimize exposure

it’s found everywhere (high dose required to infect)

Strep A disease

scarlet fever, strep throat, cellulitis, necrotizing fascitis

Strep A transmission

person to person

fomite

Strep A virulence factors

capsule

M proteins: block C3B binding

C5a peptidase: block inflammation

attack immune system

M & F proteins: function as adhesions, cell invasion by disrupting tight junctions

toxins: exotoxins, enterotoxins, superantigens

Strep A treatment

antibiotics

-NO resistance

Strep A prevention

don’t share a toothbrush with others and toss personal hygiene items post-infection

Strep B disease

neonatal infections

Strep B epidemiology

newborns exposed to bacteremia, pneumonia, and meningitis

Strep B transmission

vaginal birth

Strep B virulence factors

capsule

M proteins: block C3B binding

C5a peptidase: block inflammation

attack immune system

M & F proteins: function as adhesions, cell invasion by disrupting tight junctions

toxins: exotoxins, enterotoxins, superantigens

Strep B treatment

antibiotics

-NO resistance

Strep B prevention

treat women with Type B with antibiotics before birth

S. pneumonia disease

pneumonia

S. pneumonia epidemiology

shows up on x-rays as cloudiness in the lungs

S. pneumonia transmission

respiratory

S. pneumonia virulence factors

capsule

M proteins: block C3B binding

C5a peptidase: block inflammation

attack immune system

M & F proteins: function as adhesions, cell invasion by disrupting tight junctions

toxins: exotoxins, enterotoxins, superantigens

S. pneumonia treatment

antibiotics

-NO resistance

S. pneumonia prevention

vaccine that recognizes and attacks the capsule

Enterococcus epidemiology

normal flora of GI tract

-bad when normal flora is disrupted

Enterococcus transmission

person to person

fomite

disruption of normal flora

Enterococcus virulence factors

wide growth range

-aerobic and anaerobic

-high salt capacity

-broad pH

biofilm formation

drug resistance

Enterococcus treatment

antibiotics

-has resistance

Bacillus species

B. anthracis (Anthrax)

B. cereus

B. anthracis epidemiology

forms spores

-live in vegetative state in environment

-travel far through aerosols

B. anthracis transmission

ingestion: consumption of contaminated soil/grass

cutaneous: bacteria leave spore when barrier or skin is broken

inhalation

B. anthracis virulence factors

capsule

toxins

-exotoxins

—>edema toxin: PA+LF

—>lethal toxin: LF+EF

B. anthracis treatment

antibiotics

-resistance

B. anthracis prevention

vaccine for animals

-contains toxoid

B. cereus epidemiology

major cause of food poisoning

B. cereus transmission

ingestion of contaminated food

B. cereus virulence factors

exotoxin

-emeric form = heat stable

→causes vomiting

→short onset and duration

-diarrheal form = heat liable

→causes diarrhea

→longer onset and duration

B. cereus treatment

antibiotics

-resistance

pesto bismol

B. cereus prevention

cook/store food properly

Listeria epidemiology

grows at 4 C, high salt concentration, and wide pH

-difficult to inhibit bacterial growth

live/replicate in and outside the cell

-facultative intracellular pathogenListeria

Listeria transmission

contaminated food/dairy

Listeria virulence factors

cell invasion

-escape the lysosome and make the cell a new home for reproduction

Listeria treatment

antibiotics

-resistance

self-limiting

-immune system kicks and resolves infection on its own in healthy individuals

Listeria prevention

minimize exposure by cooking food properly

avoid raw dairy, raw veggies, and undercooked meat

Listeria disease

diarrhea, spontaneous abortion, meningitis

Corynebacterium species

C. diphtheriae (Diphtheria)

C. diphtheriae epidemiology

normal flora

can live with or without oxygen

-facultative anaerobe

C. diphtheriae virulence factors

exotoxin (A-B)

-released due to signal

-regulated expression

-toxin (A) blocks eukaryotic translation

C. diphtheriae treatment

antibiotics

-NO resistance

passive immunization against exotoxin

C. diphtheriae prevention

vaccination

-diphtheria toxoid (DTaP)

C. diphtheriae disease

death of cell (tissue/organ)

-non-healing ulcers from cutaneous infection

-lung

-heart

Clostridium epidemiology

environmental (found in soil, water, sewage, normal flora)

spore forming

obligate anaerobe: cannot live in the presence of oxygen

Clostridium species

C. difficile, C. perfinges, C. tetani, C. botulinumC. difficile

C. difficile transmission

growing

-normal flora (spread with antibiotic usage)

spores

-hospital acquisition

-fecal-oral

C. difficile virulence factors

exotoxin (A-B)

C. difficile disease

Mild

-diarrhea

Severe

-colitis

C. difficile treatment

antibiotics

-NO resistance

fecal transplantC. difficile

C. difficile prevention

proper antibiotic usage

hygiene

C. perfinges transmission

Growing

-contaminated food (meat)

→grow in room temp to warm temperatures

Spores

cutaneous

C. perfinges virulence factors

neurotoxin

C. perfinges disease

Mild

-cellulitis: bacterial infection of the skin

Severe

-myonecrosis

C. perfinges treatment

antiobiotics

-NO resistance

debridement

C. perfinges prevention

cooking of food

C. tetani transmission

spores

-cutaneousC. tetani

C. tetani virulence factors

neurotoxin prevents neuron from signaling muscles

C. tetani disease

Mild

-local muscle spasms

Severe

-systemic muscle spasms

C. tetani treatment

antibiotics

-NO resistance

debridement

passive immunization

C. tetani prevention

vaccination

-toxoid (DTaP)

C. botulinum transmission

Spores

-contaminated food (canned food, infant formula, dairy)

C. botulinum virulence factors

neurotoxin

C. botulinum disease

Severe

-botulism: paralysis and respiratory arrest

C. botulinum treatment

antibiotics

-NO resistance

passive immunization

C. botulinum prevention

proper canning

proper food preperation (heat)

Mycobacterium species

tuberculosis

Mycobacterium epidemiology

~1/3 of the world is infected

-restricted to humans

Mycobacterium transmission

aerosols

-hacking cough and blood in sputum

Mycobacterium virulence factors

intracellular pathogen

-prevents fusion to lysosome

-able to be controlled but not cleared

→chronic infection

granuloma: TB is contained in this structure of immune cells to contain it in the body without an active infection

Mycobacterium disease

respiratory infection

-blood in sputum

systemic in immunocompromised

Mycobacterium treatment

controlled in most healthy individuals

antibiotics

-resistance

→long process because of slow growth

→multiple drugs are given at once because of multi-drug resistance

Mycobacterium prevention

TB test

vaccination: live-attenuated

-not in US

Mycobacterium immunocompromised populations

tuberculosis is active in immunocompromised patients

-transplant recipients

-young and old

-immunosuppressant infections (AIDS) and genetics

-people on immunotherapies (chemo)

types of classification

macroscopic, microscopic, phenotypic, antigenic, molecular

spores

enter dormant state, extremely stable place for bacteria to live and be transported before coming out and growing

capsule

sugar coating on the outside of bacteria that prevent it form being phagocytised

flagellum

important way for bacteria to be able to move

pili

way for bacteria to attach

direct detection

uses conjugated anti-target antibody (antibody recognizes antigen)

indirect detection

uses conjugated secondary antibody (secondary antibody recognizes the first antibody that is bound to a pathogen to identify the pathogen)