Define bacterial transformation.
When bacteria take up free floating DNA.
Define transduction.
When bacteria get new DNA from a bacteriophage.
Define conjugation
When two bacteria hook up to share genetic material.
What are axial filaments and what do they do?
Flagella located between the outer and inner membranes of spirochete bacteria that help them move in a snake-like fashion.
Are slime-layers covalently attached to bacteria? What about capsules?
Slime layers - no
Capsules - yes
What is an endospore?
When gram-positive (only happens with gram +) bacteria go into a dormant state that is resistant to harsh environments.
What is the difference between an exotoxin and an endotoxin?
Exotoxins are secreted by live bacteria, endotoxins are released when bacteria die.
What do techoic acids and lipotechoic acids do to neutrophils?
They activate neutrophils!
Name two ways to differentiate staph from strep.
- Strep grows in chains (strep ladder), staph grows in clusters.
- Strep is catalase negative, staph is catalase positive!
Is LPS found on gram-negative, or gram-positive bacteria?
Gram-negative!
Is LPS an endotoxin?
Yeah
Do gram-positive bacteria have a periplasmic space? What is found in the periplasmic space?
No, only gram-negative bacteria have a periplasmic space (space between the inner and outer membranes).
Enzymes are found in the periplasmic space - antibiotics can be degraded here.
What is O antigen?
same thing as LPS
Which one does not cause tissue damage?
a) ETEC
b) EPEC
c) EAEC
d) EHEC
e) Shigella
a) ETEC
Name an arachidonic acid-derived molecule that causes vasodilation.
Prostacyclin - PGI2
Name the arachidonic acid-derived molecules that causes vasoconstriction.
Thromboxane A2 (TXA2), LTC4, LTE4, LTD4
Name the arachidonic acid-derived molecules that cause increased vascular permeability.
PGD2, PGE2, PGI2, LTC4, LTD4, LTE4
Name an arachidonic acid-derived molecule that promotes neutrophil chemotaxis.
Leukotriene B4 - LTB4
Name the arachidonic acid-derived molecules that inhibit chemotaxis.
Lipoxin A4 (LXA4) and Lipoxin B4 (LXB4)
Describe an uncomplicated case of a UTI.
Non-pregnant female w/ no risk factors - outpatient setting.
Should you treat asymptomatic bacteruria?
Only if the patient is pregnant or is about to have a urologic procedure performed with a high risk of bleeding.
How does one diagnose C. diff colitis?
PCR for toxin in stool or colonoscopy
Name the antibiotics used to treat non-severe as well as severe cases of C. diff colitis.
For non-severe disease: oral vancomycin or oral metronidazole.
For severe disease: oral vancomycin
Poo pills for recurrent, refractory cases
Which bugs are associated with atypical pneumonia?
- Mycoplasma pneumonia
- Legionella pneumophilia
- Chlamydophilia pneumoniae
Which bugs are associated with typical pneumonia?
- Strep. pneumoniae
2. Haemophilus influenzae
Which bugs cause bloody diarrhea?
- Shigella
- EHEC
- Campylobacter
- Non-typhi salmonella
- Yersinia
Which bugs cause watery diarrhea?
- Vibrio cholerae
- EPEC
- ETEC
Which bugs cause meningitis in neonates?
- Streptococcus agalactiae
- Listeria monocytogenes
- E. coli
Which bugs cause meningitis in young adults?
- Streptococcus pneumoniae
2. Nisseiria meningitidis
Which bugs cause meningitis in children?
- Streptococcus pneumoniae
- Haemophilus influenzae type B
- Neisseria meningitidis
Which bugs cause meningitis in older adults (over 50)?
- Streptococcus pneumoniae
- Listeria monocytogenes
- Neisseria meningitidis
Describe the pathogenesis of salmonella enteriditis.
- It is ingested and goes to the terminal ileum and colon.
- T3SS injects toxin into M cells, M cells endocytose the bacteria.
- M cells poop out the bacteria and macrophages take it up.
- Bacterial replication happens in macrophages and are released.
- Bacteria enter GI epithelial cells, staying in vacuoles to hide from the immune system.
- When bacterial LPS leaks into cytosol of GI cells –> immune response, cell death, bloody diarrhea.
Name the first line treatments for uncomplicated UTI.
- Nitrofurantoin
- Trimethoprim-sulfamethoxazole
- Fosfomycin
-uncomplicated outpatient pyelonephritis: fluoroquinolone
Which drugs would you use to treat nosocomial pseudomonas pneumonia?
- Cephalosporins
- Piperacillin
- Carbapenems
Which bugs can cause uncomplicated UTI?
- E. coli
- Klebsiella
- Proteus mirabilis
- Staph saprophyticus
Elderly men, endocarditis, colon cancer.
Strep. bovis
What is CagA?
Virulence factor of some strains of H. pylori that is associated with more severe symptoms - ulcers and cancer. It is injected by bacteria into GI cells via a T3SS and it inhibits apoptosis and promotes growth –> cancer.
What are the two most common causes of ventilator-associated pneumonia?
- Staph aureus
2. Pseudomonas