Drugs & Bugs- Lectures Flashcards
(176 cards)
1
Q
Bacteria and archaea are both (prokaryotes/eukaroytes) but only _ can cause disease
A
Bacteria and archaea are both prokaryotes but only bacteria can cause disease
* Prokaryotes are unicellular
* Like eukaryotes they have a cell membrane, cytoplasm, ribosomes, and DNA
2
Q
Fungi, helminths, protozoa, and algae are all (prokaryotes/ eukaryotes)
A
Fungi, helminths, protozoa, and algae are all eukaryotes
* Fungi, helminths, and protozoa can cause disease
* Because they are eukaryotes they have a nucleus and membrane bound organelles
3
Q
Bacteria that are vibrio have _ shape
A
Bacteria that are vibrio have comma-like shape
4
Q
We call bacteria that are spiral-shaped _ and bacteria that are corkscrew-shaped _
A
We call bacteria that are spiral-shaped spirillum and bacteria that are corkscrew shaped spirochete
5
Q
The cell wall provides the bacterium with rigidity and shape; also prevents osmotic shock; it contains _
A
The cell wall provides the bacterium with rigidity and shape; also prevents osmotic shock; it contains peptidoglycan
6
Q
The outer membrane is only found in _ bacteria and its major component is _
A
The outer membrane is only found in gram-negative bacteria and its major component is LPS
7
Q
Identify the nucleoid and cell wall
A
8
Q
(Gram-positive/ gram-negative) has porins
A
Gram-negative has porins
9
Q
(Gram-positive/ gram-negative) has LPS or “endotoxin”
A
Gram-negative has LPS or “endotoxin”
10
Q
(Gram-positive/ gram-negative) has teichoic acid and lipoteichoic acid
A
Gram-positive has teichoic acid and lipoteichoic acid
11
Q
(Gram-positive/ gram-negative) has thick peptidoglycan
A
Gram-positive has thick peptidoglycan
12
Q
(Gram-positive/ gram-negative) has a periplasm
A
Gram-negative has a periplasm
(between the cytoplasmic membrane and the outer membrane)
13
Q
Both gram-positive and gram-negative bacteria have a cell wall that is composed of peptidoglycan; peptidoglycan is made up of repeating units of alternating sugars, _ and _
A
Both gram-positive and gram-negative bacteria have a cell wall that is composed of peptidoglycan; peptidoglycan is made up of repeating units of alternating sugars, NAM and NAG
14
Q
Peptide chains of amino acids get added to (NAM/NAG)
A
Peptide chains of amino acids get added to NAM
* Strands are cross-linked by peptide bonds
15
Q
_ is the enzyme that catalyzes the bond between sugars (NAM and NAGs)
A
Transglycosylase is the enzyme that catalyzes the bond between sugars (NAM and NAGs)
16
Q
_ is the enzyme that catalyzes the bond between peptide chains
A
Transpeptidase is the enzyme that catalyzes the bond between peptide chains
17
Q
What are the three domains of the outer membrane?
A
Outer membrane:
1. Lipid A : endotoxin
2. Core of conserved sugars
3. O-antigen: polysaccharide; O serotyping
Recall that only gram-negative bacteria have an outermembrane and LPS
18
Q
_ have their own outer membrane with a thick, waxy coat of mycolic acid (no LPS); they are neither gram-positive or gram-negative and have to be identified using _
A
Mycobacterium have their own outer membrane with a thick, waxy coat of mycolic acid (no LPS); they are neither gram-positive or gram-negative and have to be identified using acid-fast staining (aka Ziehl-Neelsen stain)
19
Q
Some bacteria (both gram-positive and gram-negative) contain a capsule external to the cell wall; it functions to protect the bacteria from _
A
Some bacteria (both gram-positive and gram-negative) contain a capsule external to the cell wall; it functions to protect the bacteria from phagocytosis
20
Q
One important example of bacteria containing a capsule is _ ; its capsule allows it to get passed the blood brain barrier and it is known to cause nuchal rigidity
A
One important example of bacteria containing a capsule is Neisseria meningitidis ; its capsule allows it to get passed the blood brain barrier and it is known to cause nuchal rigidity (neck pain/soreness)
* It’s capsule can also help to distinguish it from Neisseria gonorrhea, which does not have a capsule
21
Q
Give four examples of bacteria with a capsule
A
- Streptococcus pneumoniae
- Klebsiella pneumoniae
- Neisseria meningitidis
- Haemophilus influenzae
22
Q
The only spore-forming species of bacteria that are known are (gram-positive/ gram-negative)
A
The only spore-forming species of bacteria that are known are gram-positive
* Spores are formed during adverse environmental conditions
* They are dormant and metabolically inactive
* Internal spore stains with malachite green
23
Q
Name two important spore-forming bacteria
A
- Clostridioidies
- Bacillus anthracis
24
Q
What are the four stages of bacteria growth?
A
Lag: adapt to new environment
Log: exponential growth (binary fission)
Stationary: nutrients begin to deplete; death rate = production rate
Death: population decreases
25
What equation represents exponential bacteria growth by binary fission?
26
If oxygen is present and aerobic respiration can be carried out, _ serves as the final electron carrier and _ ATP will be produced
If oxygen is present and aerobic respiration can be carried out, **oxygen** serves as the final electron carrier and **38** ATP will be produced (glycolysis + TCA + oxidative phosphorylation)
27
Under anaerobic conditions, _ occurs and only _ ATP are produced (from glycolysis)
Under anaerobic conditions, **fermentation** occurs and only **2** ATP are produced (from glycolysis)
28
(True/ False) Oxygen kills obligate anaerobes
False; oxygen *does not* kill obligate anaerobes, **radicals (ROS)** kill obligate anaerobes
29
Obligate aerobes and facultative anaerobes will settle at the (top/bottom) of the test tube
Obligate aerobes and facultative anaerobes will settle at the **top** of the test tube --> more O2 there = more ATP
30
Facultative anaerobes vs. aerotolerant anaerobes
**Facultative anaerobes** can grow with or without O2 but will prefer O2 conditions because they can generate more ATP
**Aerotolerant anaerobes** are unaffected by the presense of O2 because they will not use it even if it is available; they only use fermentation
31
_ require lower levels of O2 (5-10%) for respiration
**Microaerophiles** require lower levels of O2 (5-10%) for respiration
32
All bacterial genetic material, whether chromosomal or plasmid, will be _ , _ , and _
All bacterial genetic material, whether chromosomal or plasmid, will be **closed** , **circular** , and **double-stranded**
33
_ are extrachromosomal and replicate independently of the chromosome; they often carry virulence factors or antibiotic resistance genes
**Plasmids** are extrachromosomal and replicate independently of the chromosome; they often carry virulence factors or antibiotic resistance genes
34
Bacterial chromosomal dsDNA replicates at a single origin of replication and requires _ enzyme
Bacterial chromosomal dsDNA replicates at a single origin of replication and requires **DNA-dependent DNA polymerase**
35
There is only one mechanism of vertical gene transmission and that is _
There is only one mechanism of vertical gene transmission and that is **binary fission** --> yields identical progeny
36
Horizontal gene transfer between bacteria can occur by one of three mechanisms:
Horizontal gene transfer between bacteria can occur by one of three mechanisms:
1. **Transformation**
2. **Transduction**
3. **Conjugation**
*The purpose is to generate diversity (also spread resistance)*
37
If a bacteria is described as *competent*, you should think (transformation/ transduction/ conjugation)
If a bacteria is described as *competent*, you should think **transformation!**
38
What is transformation?
Bacteria lyses -->
Releases naked DNA -->
Naked DNA gets integrated into bacterial chromosome by homologous recombination
*naked DNA can be either in fragments or plasmids*
39
Bacteriophage = (transformation/ transduction/ conjugation)
Bacteriophage = **transduction!**
*The bacteriophage is a virus that infects bacteria*
40
During *lytic growth* some bacteriophage accidentally packaged up some of the bacterial DNA into the phage head; now they can inject that bacterial DNA into the next host; this is called _
During *lytic growth* some bacteriophage accidentally packaged up some of the bacterial DNA into the phage head; now they can inject that bacterial DNA into the next host; this is called **generalized transduction**
41
Recall that a bacteriphage head contains *viral DNA* --> When the bacteriphage infects the bacteria we get incorporation of the viral DNA into the bacterial DNA --> forms a prophage --> when the prophage is excised sometimes the adjacent bacterial chromosome gets removed too and now will go into the next host; this is called _
Recall that a bacteriphage head contains *viral DNA* --> When the bacteriphage infects the bacteria we get incorporation of the viral DNA into the bacterial DNA --> forms a prophage --> when the prophage is excised sometimes the adjacent bacterial chromosome gets removed too and now will go into the next host; this is called **specialized transduction**
42
_ requires direct bacterium-to-bacterium contact so that F+ plasmid can transfer 1 strand of the plasmid to the F-
**Conjugation** requires direct bacterium-to-bacterium contact so that F+ plasmid can transfer 1 strand of the plasmid to the F- --> both donor and recipient need to complete the second strand --> now both are F+
43
Antibiotic resistant genes that are encoded on F plasmids are called _
Antibiotic resistant genes that are encoded on F plasmids are called **R plasmids**
44
If the F plasmid is incorporated *into the chromosome* it is called a _ cell; importantly, when these bacterial cells undergo conjugation they do not transfer the entire chromosome so the recipient remains _
If the F plasmid is incorporated *into the chromosome* it is called a **Hfr (high frequency recombinant)** cell; importantly, when these bacterial cells undergo conjugation they do not transfer the entire chromosome so the recipient remains **F-**
45
Both gram-negative and gram-positive bacterium can have exotoxins but only _ can have endotoxins
Both gram-negative and gram-positive bacterium can have exotoxins but only **gram-negative** can have endotoxins (*they contain outer membranes)*
46
Endotoxins are the _ portion of the LPS/ outer membrane
Endotoxins are the **lipid A** portion of the LPS/ outer membrane)
* Triggers inflammatory shock
* Can induce endotoxic septic shock
47
Explain the steps of endotoxin signal transduction (that leads to endotoxic septic shock)
1. **LPS** binds to **LPS-binding protein**
2. The LPS-LBP complex binds to **host cell receptor, CD14**
3. Co-receptors **MD2** and **TLR4** come in
4. TLR4 has an transmembrane domain --> induces **intracellular signaling**
5. Activates transcription factors which promote transcription and translation of **pro-inflammatory cytokines**
48
What are the three mechanisms that are induced by endotoxins?
Endotoxin release -->
1. **Macrophage activation** (TLR4) --> produces pro-inflammatory cytokines
2. **Complement activation**: releases C3a and C5a
3. **Tissue factor activation**: activates clotting cascade (DIC)
49
Macrophage activation (TLR4) via endotoxins will manifest as _ and _
Macrophage activation (TLR4) via endotoxins will manifest as **fever** (IL-1, IL-6, TNF-a) and **hypotension** (TNF-a, NO)
50
Complement activation via endotoxins will manifest with _ and _
Complement activation via endotoxins will manifest with **histamine release** (hypotension and edema) and **neutrophil chemotaxis** (via C5a)
51
Tissue factor activation via endotoxins will manifest with _
Tissue factor activation via endotoxins will manifest with **DIC (disseminated intravascular coagulation)** aka abnormal clotting
52
Exotoxins can act (locally/ systemically/ both)
Exotoxins can act **both locally and systemically**
* Three different classes based on interaction with the host cell
53
What are type I exotoxins?
**Type I exotoxins** bind on the *surface of the host cell* and activate *intracellular pathways*
54
What are type II exotoxins?
**Type II exotoxins** are *membrane-damaging toxins*
55
What are type III exotoxins?
**Type III exotoxins** are *intracellular-acting toxins*
56
All heat-stable enterotoxins are type _ exotoxins
All heat-stable enterotoxins are **Type I exotoxins**
* *E.coli* and *Yersinia*
57
*E.coli* and *Yersinia* bind and activate _ --> which increases _ --> and leads to electrolyte and fluid loss (diarrhea)
*E.coli* and *Yersinia* bind and activate **guanylate cyclase** --> which increases **cGMP** --> and leads to electrolyte and fluid loss (diarrhea)
58
All superantigens are _ type exotoxins
All **superantigens** are **Type I exotoxins**
* Ex: *S. aureus* and *S. pyogenes*
* Causes *toxic shock syndrome*
59
Superantigens work by binding the "pocket" between _ and _ , locking them together, and producing a massive cytokine storm
**Superantigens** work by binding the "pocket" between **TCR** and **MHC II** , locking them together, and producing a massive cytokine storm
60
Type II exotoxins work by damaging cell membranes; this either occurs via enzymes that degrade the membranes directly or by forming _ in the membrane
**Type II exotoxins** work by *damaging cell membranes*; this either occurs via *enzymes* that degrade the membranes directly or by forming **pores** in the membrane
61
_ is an example of a bacteria with type II exotoxin activity; its alpha toxin oligomerizes to form pores in the cell membrane
***S. aureus*** is an example of a bacteria with type II exotoxin activity; its alpha toxin oligomerizes to form pores in the cell membrane
62
_ has an alpha toxin that has phospholipase activity --> this enzyme degrades the cell membrane and releases gas that builds up under the skin
***C. perfringens*** has an alpha toxin that has phospholipase activity --> this enzyme degrades the cell membrane and releases gas that builds up under the skin
* This is **gas gangrene**!
63
Type III exotoxins are AB toxins that act intracellularly;
The A subunit does _
The B subunit does _
Type III exotoxins are AB toxins that act intracellularly;
The A subunit **has enzymatic activity**
The B subunit **binds to the host cell** ("B for binds")
64
*Diphtheriae toxin* is a type III exotoxin; how does it function inside the cell?
*Diphtheriae toxin* **ADP-ribosylates EF-2** --> inhibits protein synthesis
* If you block an elongation factor, you block protein synthesis
65
*Cholerae toxin* is a type III exotoxin; how does it function inside the cell?
*Cholerae toxin* **ADP-ribosylates GTP-binding protein** --> increases cAMP --> watery diarrhea
66
"Rice water stools" =
"Rice water stools" = ***V. cholerae***
67
Why would WBC be normal with V. cholerae?
The bacteria itself is no problem for the body; it is the toxin that is doing all of the damage
68
Multiple gram negative bacteria carry the *cytolethal distending toxin* (ex: E.coli, C. jejuni, S. dysenteriae); how does this work?
Multiple gram negative bacteria carry the *cytolethal distending toxin* (ex: E.coli, C. jejuni, S. dysenteriae) --> triggers **DNase activity** --> chops up DNA --> cell cycle arrest
69
Cytotoxin necrotizing factor (E.coli and Yersinia) works how?
Cytotoxin necrotizing factor (E.coli and Yersinia) **activates Rho GTPases** --> alters cytoskeletal arrangements ---> induces stress fibers
70
Dermonecrotic toxin (*Bordetella*) works by activating _
Dermonecrotic toxin (*Bordetella*) works by activating **Rho GTPases** (same as cytotoxin necrotizing factor)
71
Why are microbiota/ "commensals" beneficial to us?
1. They **produce metabolites** that inhibit pathogens (like lactic acid)
2. They **block binding of pathogens** (via competitive exclusion)
3. They provide **low level immune stimulation** (so that our immune system is primed and ready)
4. They **produce vitamins** (B12, K2)
72
Nosocomial vs HAI infection
**Nosocomial** = hospital acquired
**Healthcare-associated infection** = hospital, nursing home, rehab facility, outpatient clinic
73
Name some common causes of surgical site infections (SSI)
Surgical site infections:
* *S. aureus*
* *Enterococcus*
* *E.coli*
* *P. aeruginosa*
74
Name some common causes of ventilator-associated pneumonia (VAP)
Ventilator-associated pneumonia (VAP):
* *A. baumannii*
* *P. aeruginosa*
* *S. aureus*
75
Name some common causes of central line-associated bloodstream infections (CLABSI)
Central line-associated bloodstream infections (CLABSI):
* *S. aureus*
* *S. epidermidis*
* *Candida*
* *Enterobacteriaceae* (E.coli)
76
Name some common causes of catheter-associated UTIs
Catheter-associated UTIs:
* *E.coli*
* *S. aureus*
* *S. epidermidis*
* *Enterococcus*
* *Candida*
* *P. aeruginosa*
77
Biofilms are microbial communities that adhere to surfaces like central lines and indwelling catheters; bacteria secrete _ that causes the encasing
**Biofilms** are microbial communities that adhere to surfaces like central lines and indwelling catheters; bacteria secrete **extracellular polysaccharide (EPS)** that causes the encasing
* *Can cause persistant infections (ear, dental plaque) that are hard to treat*
78
What does bacillus look like on a slide?
**Bacillus** is *gram-positive*, spore-forming
* **Green**- because of the spores
* **Boxcar**- rods are lined up in chains
79
"Reheated fried rice" think _
"Reheated fried rice" think **B cereus** aka food poisoning
80
B. cereus is _-hemolytic
B. cereus is ***beta-hemolytic*** --> complete lysis of RBCs
81
_ is a bacteria that is nonmotile, non-hemolytic, and is found in soil and livestock; it causes anthrax
**B. anthracis** is a bacteria that is nonmotile, non-hemolytic, and is found in soil and livestock; it causes anthrax
* Has a unique **D-glutamate** capsule
82
B. anthracis has two AB toxins _ and _
B. anthracis has two AB toxins **edema toxin** and **lethal toxin**
* Edema toxin: adenylate cyclase --> increases cAMP
* Lethal toxin: activates MAPK --> cell death
83
Usually B. anthracis will be treated with _ or _
Usually B. anthracis will be treated with **ciprofloxacin (FQ)** or **doxycycline (Tetracycline)**
84
Name three drugs (one is a drug class) that target the bacterial cell wall
Cell wall:
1. **Beta-lactams**
2. **Vancomycin**
3. **Bacitracin**
85
**Bacitracin** is an antibacterial that targets the cell wall and is only active against _
**Bacitracin** is an antibacterial that targets the cell wall and is only active against **Staphylococci** and **Streptococci** (gram-positives)
* Only used topically! Too toxic
86
**Vancomycin** is an antibacterial that targets the cell wall and is only active against _ ; one specific use is against _
**Vancomycin** is an antibacterial that targets the cell wall and is only active against **gram-positive**; one specific use is against **MRSA**
87
Beta-lactams like penicillin were originally only effective against _ but are now broader spectrum
**Beta-lactams** like penicillin were originally only effective against **gram-positive** but are now broader spectrum
88
The two classes of antibacterials that target the 30S ribosome are _ and _
The two classes of antibacterials that target the 30S ribosome are **Aminoglycosides** and **Tetracyclines**
89
_ antibiotics require active transport into bacteria, meaning they need oxidative metabolism, meaning they are only active against aerobes
**Aminoglycosides** antibiotics require active transport into bacteria, meaning they need oxidative metabolism, meaning they are **only active against aerobes**
90
Name two of the classes that target 50S ribosomes: _ and _
Name two of the classes that target 50S ribosomes: **Macrolides** and **Streptogramins**
91
Aside from the macrolides and the streptogramins, _, _, _ also target 50S ribosome
Aside from the macrolides and the streptogramins, **Linezolid**, **Clinadmycin**, **Chloramphenicol** also target 50S ribosome
92
Macrolides and streptogramins are mostly active against (gram-positive/ gram-negative)
Macrolides and streptogramins are mostly active against **gram-positive**
* Macrolides are huge hydrophobic molecuels that can't get through the outer membrane
93
If you wanted to use an antibiotic that targets the 50S ribosome and is effective against gram-positive *and gram-negative*, a good choice would be _
If you wanted to use an antibiotic that targets the 50S ribosome and is effective against gram-positive *and gram-negative*, a good choice would be **Clindamycin**
94
The main antibiotics that target folic acid synthesis are _ and _
The main antibiotics that target folic acid synthesis are **sulfonamides** (class) and **trimethoprim**
* Often combined, ex: TMP-SMX
95
Sulfonamides/trimethoprim are active against (gram-positive/ gram-negative/ both)
Sulfonamides/trimethoprim are active against **both gram-positive & gram-negative**
96
The major antibiotic class that targets DNA gyrase/ topoisomerase is _ and they are active against (gram-positive/ gram-negative/ both)
The major antibiotic class that targets DNA gyrase/ topoisomerase is **fluoroquinolones** and they are active against **both gram-positive & gram-negative**
97
Metronidazole targets _
Metronidazole targets **DNA integrity** (via free radicals)
98
Rifampin targets _
Rifampin targets **RNA pol**
99
Metronidazole is only active against _ type bacteria
Metronidazole is only active against **anaerobes**
* Recall it targets DNA integrity via ROS
100
Rifampin is used to treat _ bacteria
Rifampin is used to treat *Mycobacteria*
* Recall it targets RNA Pol
101
What are 4 mechanisms of antibacterial resistance?
1. **Drug inactivating enzymes** (beta-lactamase)
2. **Alteration of target molecule** (MRSA & PBP2a)
3. **Decreased drug uptake** (decrease porins)
4. **Increased drug elimination** (efflux pumps)
102
MRSA has gained resistance by altering the target molecule _ --> _
* Methicillin can no longer bind
* Comes from _ gene
MRSA has gained resistance by altering the target molecule **PBP2** --> **PBP2a**
* Methicillin can no longer bind
* Comes from ***mecA* gene**
*Normally beta-lactam drugs bind to penicillin binding proteins (PBP) to inhibit transpeptidation*
103
*E.coli* and *P. aeruginosa* can become resistant to tetracyclines or aminoglycosides via _ mechanism
*E.coli* and *P. aeruginosa* can become resistant to tetracyclines or aminoglycosides via **increasing drug elimination** (increasing efflux pumps)
104
Most antibiotics that target protein synthesis are (bacteriostatic/ bactericidal) the exceptions are _ and _
Most antibiotics that target protein synthesis are **bacteriostatic** the exceptions are **aminoglycosides** and **combined streptogramins** which are bactericidal
*Be careful, individual streptogramins are bacteriostatic*
105
Antibiotics that target folate synthesis are (bacteriostatic/ bactericidal) on their own
Antibiotics that target folate synthesis are **bacteriostatic** *on their own*
* When combined (TMP-SMX) they become *bactericidal*
106
Antibiotics that target the cell wall or cell membrane are (bacteriostatic/ bactericidal)
Antibiotics that target the cell wall are **bactericidal**
* Can't live without cell wall/ cell membrane
107
Most antibiotics that target DNA or RNA are (bacteriostatic/ bactericidal); the exception is _
Most antibiotics that target DNA or RNA are **bactericidal** the exception is *Sulfonamides* (DNA)
108
What does it mean when MBC >> MIC?
**MBC >> MIC**: drug is **bacteriostatic**
* *B stands for bactericidal*
* *I stands for inhibitory*
* It takes a lot lot more of the drug to actually kill the bacteria
* It takes much less to just inhibit growth
109
What does it mean is MBC = MIC?
MIC = MBC: drug is **bactericidal**
* At the concentration that it take to *inhibit growth* you are also *killing*
110
Kirby-Bauer Disc diffusion and the E-test are two tests that measure _
Kirby-Bauer Disc diffusion and the E-test are two tests that measure **antibiotic susceptibility**
111
112
Beta-lactam antibiotics target _
Beta-lactam antibiotics target **PBP (penicillin binding protein)** otherwise known as *transpeptidase*
113
Beta-lactams like penicillin can have a side effect of _
Beta-lactams like penicillin can have a side effect of **hypersensitivity**
* Type I, Type II, Type III, Type IV
114
Type I hypersensitivity to penicillin presents with _
**Type I** hypersensitivity to penicillin presents with **anaphylaxis**
115
Type II hypersensitivity to penicillin presents with _
Type II hypersensitivity to penicillin presents with **hemolytic anemia**
116
Type III hypersensitivity to penicillin presents with _
**Type III hypersensitivity** to penicillin presents with **serum sickness SLE**
117
Type IV hypersensitivity to penicillin presents with _
Type IV hypersensitivity to penicillin presents with **rash**
118
If patients have hypersensitivity to penicillins, a good alternative is _
If patients have hypersensitivity to penicillins, a good alternative is **monobactams** (no hypersensitivity)
* Cephalosporins are another option with low hypersensitivity risk
119
Name the three beta-lactamase resistant penicillins
1. Methicillin
2. Nafcillin
3. Oxacillin
*"NOM"* take out those beta-lactamase bugs
120
Name beta-lactam drugs from worst against beta-lactamase to best
Penicillins --> Cephalosporins --> Monobactams --> Carbapenems
*So a bug that has evolved to have beta-lactamase is best treated with carbapenems*
121
Sometimes beta-lactam antibiotics are combined with a beta-lactamase inhibitors such as _
Sometimes beta-lactam antibiotics are combined with a beta-lactamase inhibitors such as:
* **Sulbactam**
* **Clavulanic acid** (with amoxicillin = augmentin)
* **Tazobactam**
* **Cilastatin**
* **Vaborbactam**
122
_ is a drug that inhibits the transport of peptidoglycan subunits to the bacterial periplasm
**Bacitracin** is a drug that inhibits the transport of peptidoglycan subunits to the bacterial periplasm
* Normally, peptidoglycan subunits get synthesized in the cytoplasm
* They must get flipped into the periplasm
* They then get incorporated into the cell wall (transpeptidase)
*When administered, bacitracin prevents PG monomers from leaving the cytoplasm, so they never get to the cell wall*
123
The specific target for bacitracin is _
The specific target for bacitracin is **C55 isoprenyl pyrophosphate** (related to bactoprenol)
124
Vancomycin blocks peptidoglycan cross-linking (transpeptidation) by physically blocking _
**Vancomycin** blocks peptidoglycan cross-linking (transpeptidation) by physically blocking **D-Ala-D-Ala**
* *It blocks transpeptidation but not by blocking transpeptidase*
* Instead, it blocks by binding to the peptides D-Ala-D-Ala
* *Can only be given IV* because it is too big to be absorbed
* First line of defense against **MRSA**
125
Two unique side effects of vancomycin are _ and _
Two unique side effects of vancomycin are **injection site thrombophlebitis** and **Red Man syndrome**
* Red Man syndrome is a nonspecific histamine release
* Both can generally be avoided by slowing down IV administration
126
One way that vancomycin can become resistant is to mutate the peptidoglycan peptide from _ to _
One way that vancomycin can become resistant is to mutate the peptidoglycan peptide from **D-Ala-D-Ala** to **D-Ala-D-Lac**
127
_ are drugs that inhibit topoisomerase II (DNA gyrase) and topoisomerase IV
**Fluoroquinolones** are drugs that inhibit topoisomerase II (DNA gyrase) and topoisomerase IV
128
Topoisomerase II (DNA gyrase) functions to _
Topoisomerase II (DNA gyrase) functions to **unwind the DNA double helix during replication and transcription**
129
Topoisomerase IV functions to _
Topoisomerase IV functions to **decatenate, or separate the daughter chromosomes** following DNA replication
130
Most of the FQs are effective against respiratory illnesses/pneumoniae; the exception is that _ is not effective against *Streptococcus pneumoniae*
Most of the FQs are effective against respiratory illnesses/pneumoniae; the exception is that **Ciprofloxacin** is not effective against *Streptococcus pneumoniae*
131
Most of the FQs are effective against UTIs; the exception is _ because it is not cleared renally
Most of the FQs are effective against UTIs; the exception is **Moxifloxacin** because it is not cleared renally
132
Which of the FQs are effective against *Pseudomonas aeruginosa*
**Ciprofloxacin** and **Ofloxacin** are effective agaisnt *Pseudomonas aeruginosa*
133
Only one of the FQs, _ is effective against MRSA
Only one of the FQs, **Levofloxacin** is effective against MRSA
134
Arrhythmia, QT interval prolongation, Torsade de Pointes are side effects of _ drug
Arrhythmia, QT interval prolongation, Torsade de Pointes are side effects of **Fluoroquinolones**
* Moxifloxacin in particular causes cardiac side effects
* *Do not combine FQs with other K+ channel blocking drugs*
135
Photosensitivity is a toxicity of _ (primarily) but also can result from the use of _
Photosensitivity is a toxicity of **tetracyclines** (primarily) but also can result from the use of **fluoroquinolones**
136
A rash, otherwise called a type _ hypersensitivity can result from FQ use
A rash, otherwise called a **Type IV** hypersensitivity can result from FQ use
137
In very rare cases, FQ use can result in an autoimmune skin condition called _
In very rare cases, FQ use can result in an autoimmune skin condition called **Stevens-Johnson syndrome**
138
Achilles tendon rupture is a side effect of _ toxicity
Achilles tendon rupture is a side effect of **fluoroquinolone** toxicity
* Damage to cartilage and bone
* FQs should be avoided during pregnancy and in children under 8 yo; patients over 60 at increased risk
139
Trimethoprim is a competitive antagonist of _
**Trimethoprim** (folic acid synthesis diruptor) is a competitive antagonist of **dihydrofolic acid** --> blocks its binding to DHFR
140
Sulfonamides are competitive antagonists of _
**Sulfonamides** are competitive antagonists of **PABA** --> block the binding of PABA to dihydropteroate synthase
141
Sulfonamides block the step in folic acid synthesis that is catalyzed by the enzyme _
Sulfonamides block the step in folic acid synthesis that is catalyzed by the enzyme **dihydropteroate synthase**
142
Trimethoprim blocks the step in folic acid synthesis that is catalyzed by the enzyme _
Trimethoprim blocks the step in folic acid synthesis that is catalyzed by the enzyme **dihydrofolate reductase**
143
_ is a common side effect of sulfonamides and trimethoprim
**Hypersensitivity** is a common side effect of sulfonamides and trimethoprim
* Type I: anaphylaxis
* Type IV: rash
* Rare cases of Steven-Johnson syndrome
144
Jaundice and kernicterus are side effects of _
Jaundice and kernicterus are side effects of **sulfonamides**
* Sulfonamides displace bilirubin from serum albumin
145
Sulfonamides and bilirubin both compete for _
Sulfonamides and bilirubin both compete for **albumin**
146
Sulfonamides are contraindicated for patients taking _ medications because they increase the patient's bleeding risk
**Sulfonamides** are contraindicated for patients taking **warfarin** medications because they increase the patient's bleeding risk
* They inhibit **CYP2CP** --> therefore inhibit the metabolism of warfarin
* Warfarin is an anti-coagulation drug
147
Macrolides (which target 50S subunit of ribosomes) are broadly effective against gram-positive strains; it also covers one gram-negative organism, _
Macrolides (which target 50S subunit of ribosomes) are broadly effective against gram-positive strains; it also covers one gram-negative organism, **H. influenza**
148
Ototoxicity from antibiotic use is most commonly caused by _
Ototoxicity from antibiotic use is most commonly caused by **aminoglycosides**
* Can lead to permanent high frequency hearing loss
149
Aminoglycosides can cause ototoxicity and also _ toxicity
Aminoglycosides can cause ototoxicity and also **nephrotoxicity**
* Acute tubular necrosis (reversible)
150
Aminoglycosides are contraindicated in patients with _ because they inhibit Ach signaling at the neuromuscular junction
Aminoglycosides are contraindicated in patients with **myasthenia gravis** because they inhibit Ach signaling at the neuromuscular junction
151
Permanent tooth discoloration can occur in children from _ use
Permanent tooth discoloration can occur in children from **tetracycline** use
* Avoid in pregnancy and kids under 8
152
_ is a macrolide that stimulates neurons in the GI tract and triggers excess smooth muscle contraction --> cramping and diarrhea
**Erythromycin** is a macrolide that stimulates neurons in the GI tract and triggers excess smooth muscle contraction --> cramping and diarrhea
153
What are the four steps of gram staining?
1. **Gram violet** (primary stain)
2. **Iodine** (mordant)
3. **Ethanol** (decolorization)
4. **Safranin** (counterstain)
Gram negative will be blue/ purple
Gram positive will be red/pink
154
Gram positive, cocci in clusters
*Staphylococci*
155
Gram positive rods in chains
*Streptobacilli*
156
Mycoplasma are unique because they do not have a _ ; therefore they can not be gram stained
Mycoplasma are unique because they do not have a **cell wall** ; therefore they can not be gram stained
157
Chlamydia can't be gram stained because it is _
Chlamydia can't be gram stained because it is an **obligate intracellular bacteria**
158
Mycobacterium (ex: tuberculosis) can't be gram stained because of the _ in their cell wall
Mycobacterium (ex: tuberculosis) can't be gram stained because of the **mycolic acid** in their cell wall
* Must be acid-fast stained instead
159
Name some examples of bacteria that are more protected against phagocytosis due to the presense of a capsule?
* *Klebsiella pneumoniae*
* *Niesseria meningitidis*
* *Streptococcus pneumoniae*
* *Haemophilus influenzae*
160
What does E.coli look like on a slide?
E.coli has **single rods** and is **gram-negative** (pink/red)
161
What does *Bacillus subtilis* look like on a slide?
Bacillus is a **rod-shape in chains** and is **gram-positive** (blue/purple)
162
What does *Staphylococcus aureus* look like on a slide?
Staphylococcus aureus is **cocci in clusters** and is **gram positive** (blue/purple)
163
*Staphylococci* are catalase (positive/ negative)
*Staphylococci* are **catalase positive**
*A positive test means that staph is able to break down hydrogen peroxide into water and oxygen*
164
*Streptococci* are catalase (positive/ negative)
*Streptococci* are **catalase negative**
165
*S. aureus* is coagulase (postive/ negative)
*S. aureus* is **coagulase postive**
*This means when S. aureus comes in contact with blood it coats is surface with a fibrin barrier which protects it from phagocytosis*
166
*S. epidermidis* is coagulase (positive/ negative)
*S. epidermidis* is **coagulase negative**
167
Which bacteria will have positive oxidase tests?
1. *Neisseria*
2. *Pseudomonas*
3. *M. catarrhalis*
It means that they produce cytochrome c --> aerobic respiration
168
We use the optochin sensitivity test (P disc) to differentiate between _ and _ ; _ is sensitive to the test
We use the optochin sensitivity test (P disc) to differentiate between **S. pneumoniae** and **Streptococci** ;
**S. pneumoniae** is sensitive to the test
**Streptococci** is alpha-hemolytic and is resistant
169
Bacitracin sensitivity (A disc) is used to distinguish _ from the rest of its species
Bacitracin sensitivity (A disc) is used to distinguish **S. pyogenes** from the rest of its species (streptococci)
* The others are beta-hemolytic
170
The bile esculin test can distinguish _ from the other _ bacteria
The bile esculin test can distinguish **enterococcus faecalis** from the other **gamma-hemolytic** bacteria
* Black color = positive test
171
Plating on sheep blood agar is useful to test for _
Plating on sheep blood agar is useful to test for **hemolysis**
* **Alpha hemolysis**: partial RBC breakdown (green)
* **Beta hemolysis**: complete RBC breakdown (clearing)
* **Gamma hemolysis**: no RBC breakdown (no change)
172
Only species that can tolerate high salt conditions can be grown on mannitol salt agar; specifically, it differentiates pathogenic and non-pathogenic strains of _
Only species that can tolerate high salt conditions can be grown on mannitol salt agar; specifically, it differentiates pathogenic and non-pathogenic strains of **Staphylococci**
173
What does S. epidermidis look like on MSA?
***S. epidermidis*** is a **non-fermenter** (it is non-pathogenic); it does not ferment mannitol --> medium stays **pink**
174
What does S. auerus look like on MSA?
***S. aureus*** is pathogenic; it does ferment mannitol --> produces an acid that turns the medium **yellow**
175
The MacConkey agar test is going to only select for (gram-positive/ gram-negative) and it will differentiate based on the ability to _
The **MacConkey agar test** is going to only select for **gram-negative** and it will differentiate based on the ability to **ferment lactose**
* Bile salts inhibit the growth of most gram-positive bacteria
176
Bacteria that can ferment lactose cause a drop in pH that makes the MAC test _ color
Bacteria that can ferment lactose cause a drop in pH that makes the MAC test **pink**
