Exam III Microbiology: Chapter 10 Flashcards
Founded the antibiotic Penicillin in 1928
Alexander Fleming
Describe the goal of antimicrobial chemotherapy
Administer a drug to an infected person that destroys the infective agent without harming the host’s cells
What must:
Be easy to administer and able to reach the infectious agent anywhere in the body
An “ideal” drug
What are common metabolic products of aerobic bacteria and fungi that are produced to inhibit the growth of competing microbes in the same habitat?
Antibiotics
What are derived from:
Bacteria in the genera: Streptomyces and Bacillus
Molds in the genera: Penicillium and Cephalosporium
Antibiotics
Any chemical used in the treatment, relief, or prophylaxis of a disease
Chemotherapuetic Drug
Use of a drug to prevent imminent infection of a person at risk
Prophylaxis
The use of chemotherapeutic drugs to control infection
Antimicrobial Chemotherapy
All-inclusive term for any antimicrobial drug regardless of its origin
Antimicrobials
Substances produced by the natural metabolic processes of some microorganisms that can inhibit or destroy other microorganisms
Antibiotics
Drugs that are chemically modified in the laboratory after being isolated from natural sources
Semisynthetic Drugs
Drugs produced entirely by chemical reactions
Synthetic Drugs
Antimicrobials effective against a limited array of microbial types
For example: A drug effective mainly against gram-positive bacteria
Narrow (Limited) Spectrum
Antimicrobials effective against a wide variety of microbial types
For example: A drug effective against both gram-positive and gram-negative bacteria
Broad (Extended) Spectrum
What must:
Be selectively toxic - absolutely toxic to the infectious agent and absolutely nontoxic to the host
An “ideal” drug
What must:
Remain in the body as long as needed and be safely and easily broken down and excreted
An “ideal”
The nature of the microorganism causing the infection is?
One of the three factors that must be known before actual antimicrobial therapy can begin
The degree of the microorganism’s susceptibility (or sensitivity) to various drugs is?
One of the three factors that must be known before actual antimicrobial therapy can begin
The overall medical condition of the patient is?
One of the three factors that must be known before actual antimicrobial therapy can begin
What technique measures the zone of inhibition surrounding the discs, and is measured and compared with a standard for each drug?
This technique also looks for susceptibility and resistance
Kirby-Bauer technique
In which technique is the antimicrobial diluted serially in tubes of broth, each tube is inoculated with a small uniform sample of pure culture, and the smallest concentration (highest dilution) of drug that visibly inhibits growth (Minimum inhibitory concentration (MIC)?
Tube dilution tests
What are some laboratory techniques that test for drug susceptibility?
Tube dilution tests
Kirby-Bauer technique
What laboratory test can be expanded to determine a MBC (Minimum bactericidal concentration)?
Tube dilution tests
The ratio of the dose of the drug that is toxic to humans as compared to its minimum effective (therapeutic) dose is referred to as?
Therapeutic index
The higher the therapeutic index ____________?
The stronger the drug; Penicillin
Why is it necessary for a physician to record a careful history before prescribing an antibiotic?
Preexisting conditions that might influence the activity of the drug
History of allergy to a certain class of drugs
Underlying liver or kidney disease
Infants, the elderly, and pregnant women require special precautions
Name a few drug tests techniques
Laboratory tests (tube dilution tests; Kirby-Bauer technique)
Animal tests
Human Clinical Trials
Which phase is done in healthy young people (usually males) to test for toxicity?
Phase I: Human Clinical Trials (1)
Which phase is done in persons with the infection or disorder to see if the drug is effective?
Phase II: Human Clinical Trials (2)
Which phase continues phase II, but compares the drug to any current treatments on the market?
Phase III: Human Clinical Trials (3)
Which phase occurs after market studies?
Phase IV: Human Clinical Trials (4)
Inhibition of cell wall synthesis – most drugs in this category target peptidoglycan
One of the modes of actions for antimicrobial drugs
Inhibition of nucleic acid structure and function – drugs target DNA or RNA structure or synthesis
One of the modes of actions for antimicrobial drugs
Inhibition of protein synthesis – targets the prokaryotic ribosome
One of the modes of actions for antimicrobial drugs
Interference with cell membrane structure and function – targets the plasma membrane
One of the modes of actions for antimicrobial drugs
Inhibition of a metabolic process – targets a metabolic process in the microbe that is different
One of the modes of actions for antimicrobial drugs
Drugs that target the inhibition of cell wall synthesis?
most drugs in this category target peptidoglycan
Drugs that target DNA or RNA structure or synthesis?
Inhibition of nucleic acid structure and function
Drugs that inhibit protein synthesis?
targets the prokaryotic ribosome
Drugs that interfere with cell membrane structure and function?
targets the plasma membrane
Drugs that target the inhibition of a metabolic process?
targets a metabolic process in the microbe that is different
What is effective against more than one group of bacteria?
Broad-spectrum drugs
What type of drug:
Advantage is that you don’t have to know the cause of the infection first
Disadvantage is that you will kill normal flora and cause a superinfection
Broad-spectrum drugs
What drugs targets only a specific group?
Narrow-spectrum drugs
What type of drug:
Advantage is that you will not kill normal flora (at least not as much)
Disadvantage is that you must be reasonably sure of the cause of the infection
Narrow-spectrum drugs
What are microbes that were once small in number that have overgrown when normal resident biota are destroyed by broad-spectrum antimicrobials called?
Superinfection
Urinary tract infection caused by E. coli treated with antibiotics:
Lactobacilli in the female vagina are killed by the broad-spectrum tetracycline used to treat the UTI
Oral therapy with tetracyclines, clindamycin, and broad-spectrum penicillins kills off normal biota of the colon.
Overgrowth of Clostridium difficile invades the intestinal lining and releases toxins that cause diarrhea, fever, and abdominal pain.
Antibiotic-associated colitis
When a drug is altered biochemically in a lab to give it better qualities it is called a?
semisynthetic drug
It was narrow-spectrum and killed mostly Gram positive bacteria. A later version could be taken as a pill but had to be taken every 4 hours
Penicillin
What can be taken as a pill, last longer in the body and are more broad spectrum that the natural penicillins?
Semisynthetic penicillin
Antibacterials that target the cell wall?
Penicillin Clavulanic acid Cephalosporins Carbepenems Bacitracin Vancomycin Isoniazid Ethambutol
Name the drug: (targets cell wall)
Prevents the encorporation of mycolic acid in the cell wall. Used in combination with isoniazid
Ethambutol
Name the drug: (targets cell wall)
Inhibits the synthesis of mycolic acid. Used in combination therapy to treat tuberculosis and leprosy
Isoniazid
Name the drug: (targets cell wall)
Used for multi-drug resistant staph or strep infections
Vancomycin
Name the drug: (targets cell wall)
Used topically against staph and step. Found in triple antibiotic ointment
Bacitracin
Name the drug: (targets cell wall)
Good for people allergic to penicillin
Broad Spectrum
Reserved for more serious infections
Resistant to beta lactamase enzymes
Carbepenems
Name the drug: (targets cell wall)
Many generations available
Good for people allergic to penicillin
Can be affected by beta lactamase producing microbes
Cephalosporins
Name the drug: (targets cell wall)
Inhibits beta lactamase enzymes
Added to penicillins to reduce resistance
Example: Augmentin (clavulanic acid + amoxicillin)
Clavulanic acid
Name the drug: (targets cell wall)
Many semisynthetics available
Only problem in allergic reactions
Resistant microbes produce beta lactamase that break the central ring of the penicillin molecule (the beta lactam ring)
Penicillin
Antibacterials that target 70S ribosomes (protein synthesis) are?
Streptomycin
Tetracycline
Neomycin
Erythromycin
Clindamycin
Name the antibacterial that target 70S ribosomes (protein synthesis) and:
first drug to treat Gram negative infection and tuberculosis
Broad spectrum
Can cause nephrotoxicity and ototoxicity
Streptomycin
Name the antibacterial that target 70S ribosomes (protein synthesis) and:
Very broad spectrum
Can stain growing teeth brown
Causes superinfections
Tetracycline
Name the antibacterial that target 70S ribosomes (protein synthesis) and:
Treats Gram negative infection
Is nephrotoxic so is usually used topically (part of the triple antibiotic ointment)
Neomycin
Name the antibacterial that target 70S ribosomes (protein synthesis) and:
Family of antibiotics (includes the “Z pack”)
Good for patients allergic to penicillin
Used of respiratory, ear and skin infections
Erythromycin - transient deafness
Name the antibacterial that target 70S ribosomes (protein synthesis) and:
Used to treat drug resistant staph, stomach, and intestinal infections that do not respond to other medications
Good for anaerobic infections
Clindamycin
Name an antibacterial that targets microbial metabolism
Sulfonamides
What inhibits the synthesis of folic acid?
Sulfonamides
Trimethoprim is one ____________ that is used for UTI’s
Sulfonamides
What is needed to synthesize DNA and RNA nucleotides? Humans do not make their own _____ ______, but obtain it in their diet.
Folic Acid
What antibacterials targets DNA or RNA?
Fluoroquinolones and Rifamycin
What antibacterial inhibits bacterial topoisomerases or helicases
(inhibit DNA synthesis)
Fluoroquinolones
What antibacterial is used for serious infections like anthrax, kidney infections, pneumonia?
Fluoroquinolones
What antibacterial inhibits RNA synthesis?
Rifamycin
What antibacterial is used for tuberculosis (in combination with isoniazid and ethambutol)?
Also used for meningitis
Rifamycin
Name an antibacterial that targets the plasma membrane?
Polymyxin B
What antibacterial targets the plasma membrane, is most effective against Gram negative bacteria, and is typically used topically,?
Polymyxin B
What antibacterial interacts with phospholipids and distorts the plasma membrane (making it leaky), and
can be used against Pseudomonas?
Polymyxin B
Macrolide polyenes
Azoles
Echinocandins
Nucleotide cytosine analog
are all drug groups used to treat _______?
Fungal infections
Amphotericin B is a drug used to fight fungal infections. It is mostly used in an _________ form.
Injectable
__________ is an antifungal drug used to target cutaneous mycoses, vaginal and oral candidiasis, systemic mycoses
Ketoconazole
__________ is an antifungal drugs used to target AIDS-related mycoses
Fluconazole
Clotrimazole and miconazole are antifungal drugs used to treat _____________?
Infections in the skin, mouth, and vagina
What antifungal drug is rapidly absorbed orally, readily dissolves in the blood and CFS, and used to treat cutaneous mycoses?
Flucytosine
Quinine
Metronidazole
are agents to treat to __________ infections
protozoal
What antiprotozoal drug has been the principal treatment of malaria for hundreds of years?
Quinine
What antiprotozoal drug is a widely used amoebicide and general purpose antiprotozoal?
Metronidazole
What antiprotozoal drug treats Giardia lamblia and Trichomonas vaginalis?
Metronidazole
What antiprotozoal drug treats intestinal infections and hepatic disease caused by Entamoeba histolytica?
Metronidazole
These challenges of
___________ _________ include:
Their physiology is much more similar to humans.
Blocking reproduction does not affect adult worms.
Most effective drugs immobilize, disintegrate, or inhibit the metabolism of all stages of the life cycle.
Antihelminthic Drugs
___________ and ______ are antihelminthic drugs that inhibit microtubules of worms, eggs, and larvae. Used to kill roundworms
Mebendazole and albendazole
__________ is an antihelminthic drug that paralyzes the muscles of intestinal roundworms
Pyrantel
___________ an antihelminthic drug that treats tapeworm
Niclosamide
___________ is an antihelminthic drug that treats tapeworm and fluke infections
Praziquantel
_____________ is an Veterinary antihelminthic drug that treats river blindness and lymphatic filariasis in humans.
Used to prevent heartworms in dogs
Ivermectin
What type of virus does Enfuvirtide block from binding to the host cell?
HIV
Amantadine, zanamivir, and oseltamivir all block the ________ from binding
flu
Acyclovir
herpes virus
Ribavirin is an antiviral drug used to treat _____________?
RSV Lassa fever (hemorrhagic fever)
Mostly affects infants
AZT inhibits ________?
reverse transcriptase
Saquinavir inhibits ________ ?
Protease (AIDS)
What is an adaptive response in which microorganisms begin to tolerate an amount of drug that would normally be inhibitory?
Drug resistance
Drug resistance for antimicrobials is in the __________ – not the host
microbe
Acquisition of entire new genes or sets of genes via horizontal transfer from another species
is the cause of?
Drug resistance
Spontaneous mutations is the cause of?
Drug resistance
New enzymes that inactivates the drug is an example of?
Beta-lactamase
Drug resistance
Permeability of the drug is decreased is another cause of?
Drug resistance
Drug is immediately eliminated from microbe is an example of?
Drug resistance
Changing the drug’s target is a way microbe a microbe can become?
Ex: 70s ribosome changes to a different type of ribsome
Drug resistant
Change of metabolic pathway is another way microbes can become?
Drug resistant
Can replace microbes lost during antimicrobial therapy
Probiotics
Nutrients that encourage the growth of beneficial microbes
Prebiotics
