Broad-spectrum synthetic antimicrobials were discovered by
Gerhard Domagk.
An antimicrobial that inhibits cell wall synthesis will result in which of the following?
Cells become more susceptible to osmotic pressure.
Beta-lactam antibiotics have an effect on which of the following types of cells?
bacterial cells
Which of the following is a primary advantage of semisynthetic drugs?
They have a broader spectrum of action.
A medication which specifically targets cell walls that contain arabinogalactan-mycolic acid is
isoniazid.
Which of the following antibiotics disrupts cytoplasmic membrane function?
amphotericin B
A new antibacterial medication prevents the assembly of ribosomes on
mRNA. The new
medication would be
either an antisense RNA or a type of oxazolidinone.
This figure represents a Petri plate. The gray area is where bacteria
A is growing. The black area
is where bacteria B is growing. The
white area is a zone where neither organism is growing.
What is
the best interpretation of what is observed on the plate?
Bacteria B is producing an antibiotic that inhibits the growth of bacteria A.
Which of the following types of antimicrobial agent has the narrowest spectrum of action?
antivirals
The first synthetic antimicrobial widely available for treatment of infections
was an antimetabolite.
In the compound lamivudine an -SH group replaces an -OH group found
in cytosine. When
used as a medication it will
interfere with nucleic acid synthesis.
Medications which should NOT be prescribed for a pregnant woman include
sulfonamides and tetracyclines.
Which of the following can result when antibiotic therapy disrupts the normal microbiota?
both pseudomembranous colitis and thrush
A compound is extracted from a microbial culture and is modified in
the laboratory for use
as an oral medication. This product would
be a(n)
semisynthetic antimicrobial.
The CDC issued alerts about a bacterial strain known as NDM1 (New
Delhi metalo-
lactamase 1). What type of antibiotic resistance is
indicated by the name?
inactivation of the drug
Bacillus licheniformis secretes a compound that inhibits the growth
of other Gram-positive
bacteria. This is an example of a(n)
antibiotic.
Most drugs that inhibit the synthesis of the cell wall act by
preventing the cross-linkage of NAM subunits.
Most broad-spectrum antibiotics act by
inhibiting protein synthesis.
A medication that inhibits synthesis of ergosterol would be effective in treating
fungal infections.
A compound is structurally similar to PABA and inhibits folic acid
synthesis. It is most
likely a(n)
sulfonamide.
Which of the following pathways is specifically inhibited by trimethoprim?
the conversion of dihydrofolic acid to tetrahydrofolic acid
Inhibiters of DNA synthesis specifically effective on prokaryotes are
quinolones.
The cooperative activity of drugs such as beta-lactam antibiotics and
clavulanic acid, a β-
lactamase inhibitor, is known as
synergism.
Alterations in the structure of which of the following are an
important aspect of Gram-
negative bacterial resistance to
antimicrobial drugs?
porins
A sulfonamide and trimethoprim may be administered in combination to
reduce development of antibiotic resistance.
Who discovered the first antibiotic widely available to the general public?
Domagk
Bacterial DNA replication requires the enzyme gyrase, but eukaryotic
replication does not.
Ciprofloxacin ("Cipro") inhibits
gyrase activity. This is an example of
selective toxicity.
Synthetic antimicrobials that block protein synthesis by binding to the mRNA are
antisense nucleic acids.
The E-test determines which of the following?
both susceptibility and MIC (minimum inhibitory concentration)
The therapeutic range of an antimicrobial is the
range of concentrations at which the antimicrobial is both effective and non-toxic.
Which of the following interferes with cell wall synthesis by
blocking alanine bridge
formation?
both cycloserine and vancomycin
Antimicrobial sugar analogs are effective for
preventing virus attachment.
Which of the following is measured in the broth dilution test?
lack of turbidity
Infection of the ________ would be the hardest to treat with antimicrobial drugs.
brain
Disruption of the normal microbiota can result in infections caused
by which of the
following microbes?
Candida albicans, Mycobacterium, and Clostridium difficile
The β-lactams are narrow spectrum antibacterials because
the outer membrane prevents their entry into cells.
How does resistance to drugs spread in bacterial populations?
Both horizontal gene transfer and the growth of biofilms spread drug resistance.
The mechanism of action of the antibiotic vancomycin is
inhibition of cell wall synthesis.
Several antiviral medications used to treat HIV interfere with
nucleic acid synthesis.
Pentamidine is an example of an antimicrobial that
binds to DNA.
The mechanism of action of erythromycin is
inhibition of protein synthesis.
Antiviral medications can best be described as
extremely narrow spectrum synthetic antimicrobials.
Ribavirin is an antiviral that interferes with
nucleic acid synthesis.
The antimicrobial polymyxin is primarily effective for treating superficial infections with
Gram-negative bacteria.
Drug-resistant populations of microbes arise when
exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells.
Paul Ehrlich coined the term antibiotics for the "magic bullet" antimicrobials he pursued.
FALSE
Antisense nucleic acids are designed to have no side effects against humans.
TRUE
Nucleic acid analog drugs act by inhibiting ribosome function.
FALSE
A side effect known as "black hairy tongue" may result from antifungal therapy.
FALSE
R-plasmids are extrachromosomal DNAs that contain genes for antimicrobial resistance.
TRUE
Some bacterial cells are resistant to a variety of antimicrobials
because they actively pump the
drugs out of the cell.
TRUE
The outer membrane of Gram-negative bacteria enables many
antimicrobial drugs to enter the
cell more easily.
FALSE
If a subculture of an MIC test grows in an MBC test, the
concentration of the drug was
bactericidal.
FALSE
Medications administered intravenously can provide much higher
effective concentrations
than other delivery methods.
TRUE
A compound that slows the activity of efflux pumps, when administered
with an antibiotic
which requires high concentration to be
effective, the combination is highly effective for
treating
bacterial infections. This is an example of synergy.
TRUE
While not the first person to discover antibiotics _____ discovered the sources of many useful antibiotics.
Waksman
Selective _____ means that a given antimicrobial agent is more toxic
to a
pathogen than to the host being treated.
toxicity
Nucleotide or nucleoside _____ are antimicrobial agents that mimic
the
chemical structure of DNA building blocks.
analogs
The majority of broad spectrum antibacterial medications inhibit _____ synthesis.
protein
Secondary infections that result from the killing of some of the normal microbiota are called ______.
superinfections
Competition between beneficial microbes and potential pathogens is called microbial _____.
antagonism
A _____ concentration of a drug is one at which microbes
survive
but are not able to grow and reproduce.
bacteriostatic
The action of some antivirals prevent _____, an event shortly
after
entry of the virus into the cell.
uncoating
Some bacteria develop resistance to groups of drugs because the drugs
are all structurally
similar to each other; this is a phenomenon
known as _____ resistance.
cross
Second-generation drugs are semisynthetic drugs developed to combat
______
against an existing drug.
resistance
Drugs that slow bacterial growth would be _____ to
penicillin.
antagonistic
External infections can be treated by ______ administration, in which
a drug is
applied directly to the site of infection.
topical
The abbreviation _____ stands for the smallest amount of a drug that
will inhibit
the growth and reproduction of a pathogen.
MIC
Antiviral medications frequently block unique ______ to
prevent
production of new virus.
enzymes
Macrolides inhibit protein synthesis by blocking _____ of the
ribosome.
movement