Gram Pos Aerobic Rods Flashcards
What are the G+ aerobic rods that form spores and doent (2 + 3)
Spores
- Bacillus anthracis
- Bacillus cereus
No
- Listeria monocytogenes
- Corynebacterium diptheriae
- Lactobacillus spp.
What are bacterial spores and when do they form
Protective structure that some bacteria produce to increase its likihood of surviving in unfavourable env.
What is the process of sporalation up to when it pinches off
- signal is recieved and spore septum forms near one pole (becomes forespore)
- Plasma membrane surounds spore septum and pinches it off with double membrane
What is added to the forspore after pinching off
- Calcium, dipicolinic acid and loosely linked PG form a cortex around forespore (stablaize)
- bacterium addes spore coat more of pros and sugars
then released from mother cell
What is the cross section of endospore from out to in
Coat- proteins/sugars Outer membrane- mother cell Cortex- dipicholincic acid/calcium Germ cell wall- normal PG inner- spore septum
Bacillus anthracis- causes what, what it looks like on blood agar, does it move
- Causes anthrax
- Forms white/gray colonies on blood agar (medusa head, y hemolytic)
- Atrichous (doesnt move flagela)
What two plasmids in the capsul do you need for full virulence in bacillus anthracis
pXO1- anthrax toxins
pXO2- antiphagocytic capsul
What is the 3 subunits of pXO1 (anthrax toxins) that produce the affects
- Edema factor- contverts ATP to cAMP, ion influx (build up of water in tissue
- Lethal factor disrupts cell signaling pathways
- Protective antigen mediates cell entry of edema factor + lethal factor (mediates cell entry)
How can bacillus anthracis be transmitted (3) and who is at risk
-Primarly occupational hazard of vegterians, agriculture
- Cutaneous
- Inhalation
- Gastrointestinal
Cutaneous anthrax- transmission, symptoms, how common
- Entry of bacilli into wounds/abrasions
- Painless ulcer with a black necrotic center w/ inflamed tissue
- 95% of all anthrax cases
Pulmonary anthrax- transmission, symptoms, lethality
- Spores inhaled and enter respiratoryy tract
- Causes pulmonary edema + severe respiratory distress
- 70-95% fatality
Gastrointestinal anthral- transmission, symptoms
- Ingestion of undercooked meat from animal contaminated with spores
- Neusea, vomitting severe abdominal pain, dysentery
what bacteria is used as a bacterial pesticide
Bacillus thuringiensis- produces crystal proteins that have insecticidal action
What does bacillus cereus cause and why
associated with 2-5% of food poisoning
- if food is not prepared or stored properly (endospores may survive, toxigenic strains germinate in gut)
What are the 2 types of bacillus cerus
- Emetic variety
2. Diarrheal variety
What foods is the emetic variety of bacillus cerus due to, symptoms, incubation time
foods- Rice, couscous, bulgar wheat dishes
Symptoms- nausea, vommiting, cramps
incubatuon- <6hrs
What foods in the diarrheal variety of bacillus cereus due to, symptoms, incubation time
- improperly cooked/reheated meat, soups, sauces (inactivated in heat tho)
- non dysenteric diarrhea + cramping
incubatuon- 8-16 hrs
Listeria monocytogenes- blood agar type, can it survive in/out of cells, was illness is it associated w
B hemolytic
facultative intracellular
Associated with lethal type of foodborne illness called listeriosis
foods that cause listeriosis, incubation, symptoms
Consumption of deli meats, unclean raw vegs/fruit, unpasturized milks
incubation- 21 days
May cause self limiting gastroenteritis + fever (can also cross blood brain barrier causing more severe symptoms)
what is the risk of listeriosis during pregnancy
listeria can spread to placenta and may lead to spontaneous abrotion, still birth etc
How does liseria invade into cells (2)
express surface pros called internalins which allow them to be internalized into cells
when in cells they induce host actin polymerization which facilitates their invasion into neighbouring cells
How does listera evade hose immunity (1)
Listeriolysin O is used to escapse phagosomes
What does corynebacterium diptheriae cause + how it spreads
Causative agent of diphtheria, an acute upper respiratory tract infection
Repiratory droplets
what is the pathogenisis of diptheria
Toxigenic strains adhere to respiratory epithelium and secrete diphtheria toxin which attenuates protein translation
What does diptheria cause in the respiratory epithelium + systematically
pseudomembrane composed of fibrin, WBCs, RBCs, dead epithelial cells and microbes- white/grey lesion in back of throat
- also causes fever, malaise, sore throat etc
why dont commensal bac make us sick
Genetics not all strains toxic colony size where is colony immune system barriers
