Antimicrobial Drugs Flashcards
1
Q
Define Chemotherapy
A
-Anything that requires chemicals (what she said)
-the use of drugs to treat a disease (slide definition)
2
Q
Define antimicrobial drugs
A
-interfere with the growth of microbes within a host
3
Q
Define antibiotic
A
A substance produced by a microbe that, in small amounts, inhibit another microbe
4
Q
Define selective toxicity
A
-killing harmful microbes without damaging the host
(Which kills the microbe but not the host)
5
Q
Define antimicrobial drugs
A
-synthetic substances that interfere with the growth of microbes
6
Q
Who discovered penicillin?
What year?
A
-Alexander Fleming
-1928
7
Q
What red dye was used for streptococcal infections ?
A
-Prontosil red dye
8
Q
When were the first trials of penicillin?
A
1940
9
Q
What is a growing problem today with antibiotics?
A
Antibiotic resistance
10
Q
What does the term “magic bullet” mean ?
Who coined the term?
A
-kills microbes easy to make stable on shelf, safe to host
-Paul Erlich
11
Q
Penicillin is produced by what mold?
Who discovered?
What year?
A
-Penicillium
-Alexander Fleming
-1928
12
Q
Who performed the first clinical trials of penicillin?
What year?
A
-Howard Florey & Ernst Chain
-1940
13
Q
Define Narrow spectrum of Antimicrobial activity
A
-drugs that affect a narrow range of microbial Types
14
Q
Define Broad-spectrum antibiotics
A
-affect a broad range of gram-positive or gram-negative bacteria
15
Q
Narrow spectrum antibiotics are used more for ?
-eukaryotes
-prokaryotes
A
-eukaryotes
16
Q
Broad spectrum antibiotics are used more for?
-prokaryotes
-eukaryotes
A
-prokaryotes
17
Q
What antibiotic (from the slides) has the broadest spectrum ?
A
Tetracycline
18
Q
What 4 antimicrobial drugs are used for prokaryotes ?
(From the slide)
A
-isoniazid (mycobacteria)
-streptomycin (mycobacteria, gram -)
-penicillin (gram +)
-tetracycline (mycobacteria, gram -, gram +, chlamydia, rickettsia)
19
Q
What 5 antimicrobial drugs are used for eukaryotes?
(From the slide)
A
-ketoconazole (fungi)
-mefloquine [malaria] (Protozoa)
-niclosamide (Helminthes)
-praziquantel (Helminthes)
-acyclovir (viruses)
20
Q
Define bacteriocidal
A
Kills microbe directly
21
Q
Define bacteriostatic
A
-prevents microbes from growing
(Along with immune system, can clear infection)
22
Q
Define superinfection
A
Overgrowth of normal microbiota that is resistance to antibiotics
(Usually long term in the hospital )
23
Q
What are the 5 major action modes of antimicrobial drugs?
A
-inhibition of cell wall synthesis
-inhibition of protein synthesis
-inhibition of nuclei acid
-injury to plasma membrane
-inhibition of metabolite synthesis
24
Q
Explain inhibition of cell wall synthesis
(Antimicrobial drugs)
What drugs?
A
*affect cell wall
-Very selective to bacteria
-penicillins
-bacitracin
-vancomycin
-cephalosporins
25
Explain inhibition of protein synthesis
(Antimicrobial drugs)
What drugs?
*affect translation
-usually attack 70s ribosome in different places
-erythromycin,
-streptomycin
-chloramphenicol
-tetracyclines
26
Explain inhibition of nucleic acid replication & transcription
(Antimicrobial drugs)
*affect replication & transcription
-drugs that are virus specific usually
-quinolones
-rifampin
27
Explain injury to plasma membrane
(Antimicrobial drugs)
*affect plasma membrane
-very few can be used because host also has plasma membrane
-polymyxin B
28
Explain inhibition of essential metabolite synthesis
(Antimicrobial drugs)
* affect enzyme
-sulfanimide trimethoprim
29
Is polymyxin b selectively toxic?
Explain?
- it is not selectively toxic
-polymyxin b affects plasma membrane of microbes but can also damage plasma membrane of host , hence NOT selectively toxic
30
What are some inhibitors of cell wall synthesis?
Which was the first one?
-penicillin (first one)
-natural penicillins (penicillin G, original penicillin)
-semisynthetic penicillins (tweaked for resistant forms)
-extended-spectrum penicillins (tweaked for resistant forms)
31
Explain how inhibitors of cell wall synthesis works.
-does not stop current grown cell wall, only PREVENTS new cell wall forming
32
Does penicillin affect previously formed cross links of cell wall? What about new cross links?
-previous cross links are not affected, but penicillin inhibits new cross links from being formed
33
What is the active ingredient that prevents cross linking of NAM units ? (In penicillin)
- B-lactam ring
34
B-lactam ring?
Prevents the cross-linking of peptidoglycans, interfering with the cell wall construction (especially gram-positive)
35
How are natural penicillins made?
-extracted from Penicillium cultures
36
What 2 natural penicillins are there?
How are they taken ?
-penicillin G (injected)
-penicillin V (oral)
37
What is natural penicillin susceptible to ?
-penicillinases (B-lactamases)
38
How did penicillinase come to be?
Penicillinase evolved from certain microbes
39
Is natural penicillin broad or narrow spectrum?
Narrow
40
Explain semisynthetic penicillin.
Contain chemically added side chains, making them resistant to penicillinases
41
Penicillinases can affect which penicillin ?
-natural penicillin
-semisynthetic penicillin
-natural penicillin
Semisynthetic penicillin can resist penicillinases
42
Which penicillin requires injection ?
-penicillin G
43
Which penicillin can be taken orally ?
-penicillin V
44
Explain the concentration in blood of penicillin G (injection version)
-high initial concentration, but then drops quickly
(Highest concentration)
45
Explain the concentration in blood for penicillin g (oral version)
Not as high of concentration but last a little longer
(2nd highest concentration)
46
Explain the concentration in blood for procaine penicillin
Lower concentration, must be taken multiple time because of this.
(3rd highest concentration)
47
Explain the concentration in blood for Benzathine penicillin
-lowest concentration, last longest must be taken continuously
48
What are some penicillinase-resistant penicillins ?
-methicillin
-oxacillin
49
-What are some extended-spectrum penicillins
-what are they effective against ?
-aminopenicillins, ampicillin, amoxicillin
-effective against gram-negative and gram-positive
50
Explain penicillins plus B-lactamase inhibitors
-contain clavulanic acid, a non competitive inhibitor of penicillinase
51
explain Carbapenems
-substitute a C for an S and add a double bond to the penicillins nucleus
-Broad spectrum
-Primaxin, doripenem
52
Explain monobactum
-not used much because there’s better alternatives
-synthetic; single ring instead of the B-lactation double ring
-low toxicity; works against only CERTAIN gram-negatives
-aztreonam
53
What drug works similar to penicillin ?
Cephalosporins
54
Is the B-lactam ring similar or different than penicillin?
Different
55
Some polypeptide antibiotics?
-bacitracin (topical, works against gram +)
-vancomycin (keeps cell from secreting NAG, NAM)
*Glycopeptide
*Last line against antibiotic resistant MRSA
56
What antibiotic is considered a “last resort” for antibiotic resistant MRSA?
Vancomycin
57
2 antimycobacterial antibiotics?
-Isoniazid (INH)
*inhibits mycolic acid synthesis in mycobacteria
-Ethambutol
*inhibits incorporation of mycolic acid into the cell wall
58
Isoniazid and ethambutol will work for people who have ?
-tuberculosis
-leprosy
59
How does Inhibition of cell wall synthesis work?
-prevents bacteria from increasing the amount of peptidoglycan by interfering cross bridge formation
60
Does cell wall synthesis inhibitors work on fully formed bacteria? Y/N
Explain
NO, it only inhibits new cross bridges from forming, does not affect previously formed cross bridges
61
What phase does cell wall synthesis inhibitors affect?
Log phase of growth curve
62
Do cell wall synthesis inhibitors affect plant or animal cells ?
Explain ..
-Does NOT affect either because neither have peptidoglycan
63
What do protein synthesis inhibitors do?
Examples of some
-target bacterial 70s ribosomes
-chloramphenicol, erythromycin, streptomycin, tetracyclines
64
*** KNOW THIS
What does chloramphenicol do ?
Binds to 50s portion and inhibits formation of peptide bond
65
*** KNOW THIS
What does erythromycin do ?
Binds to the 23s rRNA molecule in the 50s subunit not allowing tRNA to attach
66
*** KNOW THIS
What does tetracyclines do ?
Interfere with attachment of tRNA to mRNA-ribosome complex
67
*** KNOW THIS
What does streptomycin do ?
Changes shape of 30s portion, causing code on mRNA to be read incorrectly
68
Is chloramphenicol broad or narrow spectrum ?
-broad spectrum
69
What does chloramphenicol do?
-inhibits peptide bond formation
-can suppress bone marrow and affect blood cell formation
70
What antibiotic should NOT be given to children or pregnant women ?
Explain.
-Chloramphenicol
-suppresses bone marrow and affect blood cell formation
71
What are antibiotics that should NOT be used during pregnancy?
-chloramphenicol
-streptomycin
-kanamycin
-tetracycline
-bactrim
-ciprofloxacin
-furadantin
-macrodantin
-macrobid
-minocyline
-Septra
-aminoglyosides
-
72
Why can’t streptomycin, kanamycin & tetracycline be used during pregnancy ?
-They are teratogenic (agent causing malformation in embryo)
-Streptomycin & kanamycin can cause hearing loss
-tetracycline can lead to weakening hypoplasia and discoloration of long bones and teeth
73
Characteristics of aminoglycosides
-amino sugars linked by glycoside bonds
-change the shape of the 30s subunit of the 70s ribosome
-can cause auditory damage (not recommended for pregnant)
-streptomycin, neomycin, gentamicin
-teratogenic. — harmful to a pregnancy
74
Define teratogenic
-harmful to a pregnancy
75
Characteristics of tetracyclines
-produced by streptomyces spp.
-interfere with the tRNA attachment to the ribosome
-broad spectrum penetrates tissues, making them valuable against rickettsias and chlamydias
-can suppress normal intestinal microbiota
76
What is good against rickettsias and chlamydias?
Tetracyclines
77
What can kill normal intenstinal microbiota ?
Should probiotics be taken with this ?
-tetracyclines
-since intestinal microbiota can be affected, probiotics SHOULD be taken with tetracyclines
78
What are some protein synthesis inhibitors ?
-glycylcyclines
-macrolides
79
Characteristics of glycylcyclines
-broad spectrum; bacteriostatic
-bind to the 30s ribosomal subunit
-inhibits rapid effluent; administered intravenously
-useful agains MRSA
80
Characteristics of macrolides
-Contain a macrocyclic lactose ring
-narrow spectrum against gram-positives
*erythromycin
81
Example of macrolide?
Erythromycin
82
Describe erythromycin
“Large & spiky”
83
Other antibiotics that inhibit proteins synthesis and attach to 50s or 30s subunits of ribosome
-streptogramins
-oxazolididnones
-pleuromutilins
84
Stretpogramins attach to what ?
50s subunit
85
Streptogramins work against gram _________ that are _______to other antibiotics
-positive
-resistant
86
Oxazolidinones bind to ?
-50s/30s subunit interface
87
Oxazolidinones helps combat ?
Is it natural or synthetic?
-MRSA
-synthetic
88
Pleuromutilins are effective against what?
How is it administered ?
-gram positives
-topical
89
What causes injury to the plasma membrane ?
-lipopeptides
-polymyxin B
-amphotericin B
90
Inhibition of nucleic acid synthesis, what are the effects?
-interfere with DNA replication replication and transcription
-nucleoside analogs (used against viruses)
(Viruses dont have any proofreading, that’s how its used)
91
Inhibition of synthesis of essential metabolites, what are the effects.
-anti-metabolites compete with normal substrates for an enzyme
*sulfanilamide competes with para-aminobenzoic acid (PABA), stopping the synthesis of folic acid.
*main metabolite pathway attacked is the pathway that makes folic acid.
*bacteria have to make own folic acid
92
What are some nucleic acid inhibitors ?
-Rifamycin
-quinolone & fluoroquinolones
93
What does rifamycin do ?
-inhibits mRNA synthesis
-penetrates tissues; antitubercular activity
94
What do quinolone and fluoroquinolones do ?
-Nalidixic acid inhibits DNA gyrase , is synthetic
-norfloxacin and ciprofloxacin is broad spectrum, affects normal flora, so usually last choice
95
Characteristics of sulfonamides
-inhibit the folic acid synthesis needed for nucleic acid and protein synthesis
-competitively bind to the enzyme for PABA production, a folic acid precursor
-combination of trimethoprim and sulfamethoxazole (TMP-SMZ) is an example of a drug synergism
96
What are some anti fungal drugs that inhibit ergosterol synthesis?
-Polyenes
-S Amphotericin B
-azoles
-miconazole
-triazole
-allylamines
-for azole-resistant infections
97
Example of anti fungal that affects fungal cell wall?
Echinocandins - inhibit synthesis of B-glucan
98
Example of antifungal that inhibit nucleic acid
Flucytosine- cytosine analog interferes with RNA synthesis
99
characteristics of griseofulvin
-produced by penicillium
-inhibits microtubule formation
-active against superficial dermatophytes
100
What is tolnaftate used for ?
Athletes foot
101
What does pentamidine do?
-anti pneumocystis; may bind to DNA
102
What is the newest drug?
Antiviral drug
103
What do antiviral drugs do ?
-Block receptors on host cell
-Block entry/exits from host cell
104
Antiviral drugs are entry and fusion inhibitors , explain
-block the receptors on the host cell that bind to the virus
-block fusion of the virus and cell
105
Antiviral drugs additional functions: uncoating, genome integration, and nucleic acid synthesis inhibitors. Further explain .
-prevent viral uncoating
-inhibit viral DNA integration into the host genome
-nucleoside analogs inhibit RNA or DNA synthesis
106
Acyclovir is a treatment for what ?
Herpes
107
What are usually good for RNA viruses?
Interferons
108
What promotes interferon production ?
Imiquimod
109
Explain interferons
-produced by viral-infected cells to inhibit further spread of the infection
110
Antivirals for treating HIV/AIDS?
Antiretroviral
-nucleoside analog (zidovudine)
-nucleotide analog (tenofovir)
-non-nucleoside inhibitors (nevirapine)
-protease inhibitors (raltegravir)
-integrase inhibitors (miraviroc)
-fusion inhibitors (enfuvirtide)
Various combinations for each pt
111
What are some anti protozoan drugs? (Mostly preventative)
What does it treat ?
-Quinine & chloroquine
-malaria
112
Where is artemisinin harvested from ?
A plant
113
What does artemisinin kill ?
Kills plasmodium that causes malaria
114
What is the standard for most parasitical infections and C. Dif?
Metronidazole (flagyl)
115
What does metronidazole (flagyl) interfere with?
-interferes with anaerobic bacteria
116
What does metronidazole treat?
-Trichomonas
-giardiasis
-amebic dysentery
117
Some anti Helminthic drugs?
-niclosamide
-praziquantel
-mebendazole & albendazole
-ivermectin
118
What does niclosamide do?
What does it treat?
-prevents ATP
-treats tapeworms
119
What does praziquantel do ?
What does it treat ?
- alters membrane permeability
-treats tapeworms & flukes
120
What does mebendazole & albendazole do ?
What does it treat ?
-interfere with nutrient absorption
-treat intestinal helminths
121
What does ivermectin do?
What does it treat?
-paralysis of helminths
-treats roundworms and mites
122
What can lead to antibiotic resistance ?
-a variety of mutations
123
Resistance genes are often on ______________ or ___________ that can be transferred between bacteria.
-plasmids
-transposons
124
How does antibiotic resistance work ?
Can get resistance from a plasmid gene because bacteria multiplies fast and has many generations it can mutate easier.
Usually when a DNA is altered so is a protein
125
What is the mechanism of resistance?
1. Blocking entry
2. Inactivation by enzymes
3. Alterations of target molecule
4. Effluent of antibiotic
126
Resistant antibiotic genes can form eflux pump that inactivate?
-Penicillin
-molecule
127
Mechanisms of resistance (additional)
-enzymatic destruction or inactivation of the drug
-prevention of penetration to the target site within the microbe (any protein blocking drug)
-alteration of the drug’s target site (adding molecule; unrecognizable)
-variations of mechanism
128
Does mycoplasma have a cell wall?
What is it resistant to ?
-does NOT have cell wall
-resistant to penicillin
129
Define Persister cells
-microbes with genetic characteristics allowing for their survival when exposed to an antibiotic
130
Define superbug
Bacteria that are resistant to large numbers of antibiotics
131
How are resistant genes often spread ?
Horizontally among bacteria on plasmids or transposons via conjugation or transduction
132
Does someone need to finish antibiotics even if they fell better?
-Yes, so a persons immune system can get rid of microbes while antibiotics keep levels low
133
What are some misuses that create antibiotic resistance ?
-using outdated or weakened antibiotics
-using antibiotics for the common cold and other inappropriate conditions
-using antibiotics in animal feed
-failing to complete prescribed regimen
-using someone else’s leftover prescriptions
134
Define synergism
The effect of 2 drugs together is GREATER than the effect of either alone
135
Define antagonism
The effect of two drugs together is less than the effect of either one
136
Give example of antagonism
Organism that is treated with penicillin and treated with protein synthesis
137
Define efficacy
-safety & factors involved; how much needed to work
138
Another name for disk-diffusion method
- Kirby-Bauer test
139
What does the disk-diffusion method do ?
-Tests the effectiveness of chemotherapeutic agents
*paper disks s with a chemotherapeutic agent are placed
agar containing organism
*zone of inhibition - around the disk determines the sensitivity of the organism to the antibiotic
140
What determines the sensitivity of the organism to the antibiotic ?
What is this method called ?
-zone of inhibition
- Disk-diffusion method (Kirby-Bauer test)
141
What is done with the zone of inhibition ?
-diameter is measured and compared to chart to see if it is acceptable
142
What does the E TEST determine?
-determines the minimal inhibitory concentration (MIC)
*lowest antibiotic concentration preventing bacterial growth
143
What does the dilution test determine?
-determines the MIC and minimal bactericidal concentration(MBC) of an antimicrobial drug
-test organism is placed into the wells of a tray containing dilutions of a drug; growth is determined
144
What are antibiograms ?
Reports that record the susceptibility of organisms encountered clinically
145
What are examples of the future of chemotherapeutic agents?
-target virulence factors
-sequester iron, which feeds pathogens
-antimicrobial peptides produced by various organisms
-phage (bacterial virus) therapy -bacteria viruses do not harm humans
-bacteriocins: antimicrobial peptides produce by bacteria
