Chapter 1: General Microbiology Flashcards
Cytoplasmic membranes in Gram negative and gram positive bacteria contain what enzymes that helps construct the cell wall or peptidoglycan?
transpeptidases and carboxypeptidases
Toxic portion of LPS in Gram negative organisms?
lipid A
Understand this image.
NAG NaM
3rd L lysine cross links
4th and 5th Dala
link between NAG and NAM B-1,4
Bacitracin effect on PG synthesis.
Interferes with recycling of the pyrophosphobactoprenol back to phosphobactoprenol
β-lactam effect on PG synthesis?
targets the PBPs
What are resistance mechanisms used by bacteria to resist β lactams?
- decreased binding of antibiotic to the PBP
- decreased concentration of antibiotic at target (gram negative only)
- β-lactamases
What organisms have capsules? Use mnemonic to try to remember.
Some Killers Have Pretty Nice Capsules
Streptococcus pneumoniae
Klebsiella pneumoniae
Haemophiluus influenzae
Pseudomonas aeruginosa
Neisseria meningitidis
Cryptococcus neoformans
Pili/fimbriae are the primary mechanism of adherence in gram negative or gram positive cells?
gram negative
Teichoic acids are the primary mechanisms of adherence in gram negative or gram positive cells?
gram positive
What are invasins?
surface proteins that allow an organism to bind to and invade normally non phagocytic human cells; escaping the immune system
What are the best examples of organisms that have invasins?
Yersinia psedotuberculosis
What are exotoxins?
protein toxins, quite toxic and secreted by bacterial cells
Describe endotoxins?
structural toxins (i.e) LPS, Peptidoglycan, teichoic acids
Antigenic variation found evidenced in N. gonorrhoeae.
pili and outer membrane proteins
Antigenic variation
changing surface ag to avoid immune destruction
Antigenic variation example of enterobacteriaceae?
capsular and flagellar ag may or may not be expressed
Antigenic variation HIV?
antigenic drift
Antigenic variation influenza.
antigenic drift
Antigenic variation Trypanosoma brucei rhodesiense?
phase variation
Antigenic variation T.b gambiense?
phase variation
Antigenic drift?
A subtle change in the surface glycoprotein (either hemagglutinin or neuraminidase) caused by a point mutation or deletion in the viral gene
