Microbial Toxins and Antimicrobial Resistance Flashcards
_____ activates membrane-associated guanylate cyclase activity
Heat-stable enterotoxin (E coli)
_____ are hybrid molecules that have a toxin fragment and an altered receptor-binding domain that is used to target a specific population of cells (Ex. tumor cells)
Immunotoxin
_____ increase intracellular cAMP and ____ increase intracellular cGMP
Heat-labile enterotoxin (Vibrio cholerae and E coli), pertussis toxin, Anthrax edema factor, and adenylate cyclase toxin; Heat-Stable enterotoxin (E coli)
_____ is an endopeptidase that cleaves several MAP kinase kinases and inactivates their function in signal transduction
Anthrax Lethal factor
______ alter actin cytoskeleton by transferring glucose to Rho GTPases (inactivating them)
Clostridium Difficile Toxins A and B
______ can inactivate specific SNARE proteins required for neuroexocytosis
Zinc-dependent endopeptidase
______ causes flaccid paralysis of skeletal muscles by inhibiting acetylcholine release
Botulinum toxin
______ inhibit Gi and increase membrane-associated adenylate cyclase activity
Pertussis
______ remove an adenine residue from 28S rRNA, which inhibits the ribosome and protein synthesis
Shiga toxin, ricin
_______ activate Gs and increase membrane-associated adenylate cyclase activity
Heat labile-enterotoxin (Vibrio cholerae and E coli)
_______ are adenylate cyclases that enter cells and increase cAMP (require activation by calmodulin and calcium).
Anthrax edema factor and adenylate cyclase toxin
_______ causes sustained muscular contraction (spastic paralysis) of skeletal muscles by inhibiting release of neurotransmitters from inhibitory interneurons in the spinal cord
Tetanus toxin
_______ inhibit EF-2 via ADP-ribosylation, which inhibits protein synthesis
Diphtheria toxin and Pseudomonas aeruginosa exotoxin A
Altered PBPs (2), organism, affected drug class
mecA (Staphylococci) and Mosaic PBPs (Strep pneumoniae and Neisseria gonorrhoeae); Beta-lactams
AmpC Beta-lactamase differs from narrow and extended spectrum beta-lactamases in that it is ______. Found in _______.
Not affected by Beta-lactamase inhibitors; Enterobacter and Pseudomonas (c)
Antimicrobial resistance to _____ is intrinsic in anaerobic bacteria that do not have a necessary electrochemical gradient for drug molecules to enter
Aminoglycosides
Antimicrobial resistance to _____ occurs via dimethylation of 23S rRNA.
Macrolides
Antimicrobial resistance to _____ occurs via methylation of the 16S rRNA.
Aminoglycosides
Antimicrobial resistance to _____ occurs via mutations in the QRDR.
Quinolones
Antimicrobial resistance to _____ occurs with constitutive expression of erm; this drug does not induce erm
Clindamycin
Antimicrobial resistance to ______ occurs due to the ___ gene which expresses ______ ribosome methylase
Macrolides; erm; erythromycin
Antimicrobial resistance to ______ occurs via a change in the terminal five-member peptide in peptidoglycan (Organism: ______)
Vancomycin; enterococcus
Antimicrobial resistance to ______ occurs via N-acetylation, O-phosphorylation, or O-nucleotidylation of the drug
Aminoglycosides
Bla is a narrow spectrum beta-lactamase, most commonly found in _______.
Staphylococci
Carbapenemases: plasmid vs. chromosome, drug resistance, organism
plasmid; All beta-lactams and carbapenems; Klebsiella
Carbapenemases (2)
Klebsiella Pneumoniae Carbapenemase (KPC) and New Delhi Metallobetalactamase-1 (NDM-1)
Common methods of resistance that decrease drug access to target (2)
Porins, efflux pumps
CTX-1 is a/an ______ spectrum beta-lactamase, mostly found in ______.
extended; E. coli
Extended spectrum Beta-lactamases (2), plasmid vs. chromosome, drug resistance
CTX-M (p) and SHV-type (p); PCNs, ampicillin, and Cephalosporins
Inducible genes conferring resistance
AmpC (PCNs, ampicillin, and cephalosporins) and erm (macrolides and clindamycin)
Lipopolysaccharides of gram-negative bacteria may be referred to as _____ due to association with cells.
Endotoxin
Macromolecular products of microbes that cause harm to susceptible animals by altering cellular structure or function
Microbial Toxins
Mechanims of microbicidal action (3)
Inhibit cell wall synthesis, Disrupt cell membrane, Interfere with DNA function/synthesis
Mechanism of microbial toxin action: adenylate cyclase toxin
Modify intracellular pathways
Mechanism of microbial toxin action: Anthrax edema factor and lethal factor
Modify intracellular pathways
Mechanism of microbial toxin action: Botulinum and Tetanus
Inhibit neurotransmitter release
Mechanism of microbial toxin action: Clostridium difficile Toxins A and B
Modify intracellular pathways
Mechanism of microbial toxin action: Diphtheria toxin and Pseudomona aueruginosa exotoxin A
Inhibit protein synthesis
Mechanism of microbial toxin action: Heat-labile enterotoxin (Vibrio cholerae and E coli)
Modify intracellular pathways
Mechanism of microbial toxin action: Heat-stable enterotoxin (ST-I of E coli)
Modify intracellular pathways
Mechanism of microbial toxin action: hemolysins
Damage cell membranes
Mechanism of microbial toxin action: hyaluronidase, collagenase, elastase
Facilitate microbe spread through tissue
Mechanism of microbial toxin action: pertussis toxin
Modify intracellular pathways
Mechanism of microbial toxin action: pyrogenic exotoxins, including enterotoxins and Toxic Shock Syndrome Toxin (TSST-1)
Stimulate cytokine production
Mechanism of microbial toxin action: Shiga toxin, ricin
Inhibit protein synthesis
Mechanism of microbial toxin action: superantigens
Stimulate cytokine production
Mechanism of microbial toxin action: Zinc-dependent endopeptidase
Inhibit neurotransmitter release
Mechanisms of antimicrobial resistance (3)
Change in target, change in access to target, Drug inactivation/modification
Mechanisms of antimicrobial selective toxicity (4)
Different metabolic pathway, Different enzyme structures, non-existent structural feature, different structural feature
Mechanisms of microbial toxin action (6)
Facilitate microbe spread through tissue, damage cell membranes, stimulate cytokine production, Inhibit protein synthesis, modify intracellular pathways, inhibit neurotransmitter release
Mechanisms of microbiostatic action (2)
Inhibit protein synthesis, Inhibit metabolic pathways
Mechansms of Beta-lactam resistance (2)
Modification of PBP, Modification by Beta-lactamases
Narrow spectrum Beta-lactamases (3), plasmid vs. chromosome, and drug resistance
Bla (p), TEM-1 (p), SHV-1 (c); PCNs and ampicillin
Renal dosing required (6)
Penicillins, Cephalosporins, Carbamazepines, Vancomycin, Aminoglycosides, Fluoroquinolones
SHV-1 is a/an _______ spectrum beta-lactamase, most commonly found in _______.
narrow; Klebsiella pnuemoniae
SHV-type are _______ spectrum beta-lactamases, mostly found in ______.
extended; Klebsiella pneumonia
TEM-1 is a/an _______ spectrum beta-lactamase, most commonly found in _______.
narrow; E. coli and H. influenzae
