4 lecture peptidoglycan synthesis and antibiotics Flashcards
what blood pressure is considered to be hypotensive?
Any systolic blood pressure below 90/x is considered hypotension.
what is macular erythroderma?
a skin condition characterized by flat reddened skin.
what is the number one thing you do for a septic patient to control their blood pressure?
give them fluids and electrolytes.
If you take cultures and find out that the bacteria you are dealing with is MRSA, what antibiotic do you quickly give?
1) vancomycin
What does CA-MRSA mean? What toxin does it release?
1) Community associated Methacillin resistant S. Aureous.2) The toxin it releases is enterotoxin C
Why would you ever give IVIG’s?
During sepsis with excess superantigen release. IG’s bind up the Toxin.
The peptidoglycan wall is bound by which two types of covalent bonds?
1) glycosidic2) peptide
what happens to bacteria that do not have an intact cells wall?
they lyse due to turgor pressure
When does peptidoglycan synthesis/hydrolysis occur in normal bacterial cultures?
during cell division
T/F Peptidoglycan is unique to bacteria?
True. (many antibiotic targets)
Where is the gram - peptidoglycan layer located?
within the periplasm
what percentage of gram + peptidoglycan is cross linked? Gram -?
1) 75%2) 25%
what is the reason for the decreased cross linking in gram - bacteria compared to gram +?
It is because the peptidoglycan of a gram - bacteria is partially covalently bound to lipoproteins.
what kind of covalent bond binds NAG to NAM?
Beta 1-4 glycosidic bond
how do you make NAM?
NAG + lacteal group
what group carries the tetrapeptide with alternating L and D amino acids?
The NAM is the polysaccharides that carries the four amino acids. Therefore, it is the where the cross linking is occuring. NAM to NAM
What makes the peptide cross link that connects the 4th amino acid of one NAM to the 3rd amino acid of another NAM?
5 glycine residues
To make NAG into Nam, where does the lacteal group have to be attached?
The lacteal group attaches to the C3 carbon
T/F Only MA carries the tetrapeptide chains?
True. Recall that MA=NAM
What is so significant about the D amino acids in the bacterial cell wall?
The body cannot breakdown/process D amino acids and they are only found in bacteria.
Which amino acids make up the tetrapeptide link?
1) L-alanine2)D-Glutamate3)L-lysine or diaminopimelic acid4)D-alanine
Penicillin and cephalosporin do what?
They block the enzymes that form the crosslink between the 3rd and 4th amino acid that is connected to NAM. This disrupts the formation of peptidoglycan.