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| Bacteria are diploid or haploid? |
Haploid |
| Bacteria have nuclear membrane? |
No |
| What is bacterial genetic transformation? |
Naked DNA released during cell lysis --> bind to cell wall of competent bacteria (has structures on cell wall that can bind and take up the fragments) of the same species or closely related --> DNA incorporated into the genome (must have enough homology) |
| How can genetic transformation be used for genetic mapping? |
The frequency of two traits being passed on together depends on the distance apart on the genome. The closer they are, the more likely they will be passed on together. |
| what is a bacteriophage? |
Virus that infects bacteria |
| Virulent phage vs. temperate phage |
virulent lyses and kills bacteria (generalized transduction); temperate incorporates the DNA into its own genome (specialized transduction) |
| What is prophage? |
"temperate" piece of viral DNA that infects bacteria and is incorporated into the bacterial genome |
| Transformation - how much homology required? |
Need to be of the same species because the DNA fragments taken in need to be incorporated into the recipient's genome. |
| Generalized transduction - how much homology required? |
virulent phage injected --> destroys bacterial genome (some pieces of bacterial genome left) --> bacterial genome packaged into capsid --> injected into another bacteria --> if there is HOMOLOGY, then bact chrom is incorporated into new bacteria. |
| Conjugation - how much homology required? |
Can occur between unrelated bacteria (sex pili required) |
| Transposons - how much homology required? |
No DNA homology required; this genetic material can move between different bacterial genera |
| Lysogenic immunity |
prophage (temperate phage that is incorporated into bacterial genome) blocks a subsequent infection by a different phage |
| Lysogenic conversion |
when gene is transferred from one bacteria to another by specialized transduction and incorporated into genome of new bacteria |
| What is the major mechanism for transfer of antibiotic resistance? |
Conjugation because can occur between unrelated bacteria |
| What do F plasmids look like? |
circular, double stranded |
| What is an Hfr cell? |
bacterial cell that just received an F plasmid incorporates that F plasmid into its own genome |
| What is an F' plasmid? |
F plasmid from an Hfr cell that gets excised, but now with a part of that bacteria's chromosome as well -- so now have DNA from two different bacteria |
| You have gram positive cocci -- if you see bubbles on a catalase test (slide with H2O2), what do you have? |
Staph |
| On a blood agar plate testing for hemolysis, if you see a clear zone around a plated colony, what do you know? |
B hemolytic (lyse all the RBC's around the colony with Streptolysins O and S); could be strep pyogenes or GBS) |
| On a blood agar plate testing for hemolysis, if you see a green zone around a plated colony, what do you know? |
a hemolytic (only partially lyse the RBC's so the green is a Hb metabolite that's released into the area) |
| What are the encapsulated bacteria? |
Some Killers Have Pretty Nice Capsules. Strep pneumoniae, Klebsiella pneumoniae, Hemophilus influenza, Pseudomonas aeruginosa, Neisseria meningitidis, Cryptococcus neoformans |
| M protein |
on Strep pyogenes. Protein that blocks Macrophage action -- inhibits activation of complement and protects from phagocytosis. Weakness because B cells create abs to the M protein. |
| Streptolysin O |
Enzyme that is responsible for B hemolysis. Is inactivated by O2. ASO titer measures anti-streptolysin O antibodies to confirm recent infection. |
| Impetigo |
a vesicular blistered eruption, most common in children that becomes crusty and flaky, found around the mouth. Caused by strep pyogenes. |
| What is the treatment for infection by strep pyogenes? |
Penicillin G |
| What does clindamycin do for infection by strep pyogenes? |
shuts down streptococcal metabolism and blocks toxin production |
| Baby BEL |
neonatal meningitis: GBS, E. coli, Listeria monocytogenes |
| Endocarditis - subactue and acute |
Subacute: Strep viridans. Acute: Staph aureus |
| Which Strep most likely to cause abscess in brain or abdominal organs? |
Strep viridans - intermedius. |
| Which Strep most likely to cause colon cancer? |
Strep bovis |
| What is resistance mechanism for Strep group D against Vancomycin? |
Change d-ala-d-ala to d-ala-lactate! |
| Strep in UTI's and biliary tract infections |
Enterococcus faecalis |
| Lancet shaped dipplococci |
Strep pneumoniae |
| What is the major virulence factor of pneumococcus? |
polysaccharide capsule |
| What are the two main lab tests used to ID pneumococcus? |
Quellung (abs bind to capsular antigens --> capsule swells); optochin (S. pneum growth will be inhibited, while S. viridans will continue to grow) |
| Most common cause of pneumonia in adults |
Strep pneumoniae (typicl community acquired pneumonia) |
| Most common cause of otitis media in children |
Strep pneumoniae |
| Most common cause of bacterial meningitis in adults |
Strep pneumoniae |
| Most common cause of septic arthritis in children and elderly (over 50) |
Staph aureus (infection of synovial membrane in joints - synovial fluid will reveal infective organisms) |
| What two organisms most likely are the cause of skin infections? |
Strep pyogenes and staph aureus |
| What is treatment for infection with MRSA (methicillin-resistant staph aureus) |
Methicillin is penicillinase-resistant drug. Can use vancomycin. |
| Infection from foley catheters or IV lines |
Staph epi |
| Infection of prosthetic devices |
Staph epi |
| Gold on sheep blood agar |
Staph aureus |
| Can you use Penicillin G for staph infections? |
No because staph makes penicillinase, which inactivates penicillin G. |
| What is coagulase and what does it do? |
In staph aureus. activates prothrombin --> causes blood to clot around the org --> protects against phagocytosis |
| Protein A |
In Staph aureus. Binds the Fc portion of IgG --> prevent opsonization |
| Food poisoning by Staph aureus lasts how long? |
Grows in food --> that food is ingested --> 12 to 24 hrs. |
| Infection of umbilicus in neonate |
Staph aureus, scalded skin syndrome |
| UTI's in sexually active young woman |
Staph saprophyticus |
