MED 118: CHAPTER 11. AN ULTIMATE A+ QUESTIONS
AND ANSWERS BREAKDOWN
antimicrobial
able to destroy or suppress the growth of pathogens and other micro-organisms
gram positive
organism that stains purple under a microscope, lets us know that there are fewer
layers, meaning they are more susceptible to bacterial growth.
gram negative
organism that fails to color when stained and viewed under a microscope, meaning it
has extra layers of protection against bacteria
bacteriostatic
inhibits growth of bacteria, keep bacteria from replicating. Body's immune system
required to fully eliminate the infecting bacteria
bactericidal
antibiotics that kill bacteria directly. not always the better option because it can kill some
of the host's good bacteria as well. Body's immune system NOT required for bacterial
elimination. Often more toxic
broad-spectrum antibiotic
an antibiotic that is effective against a wide range of both gram-positive and gram-
negative bacteria. this is best when the provider is working against an unknown
organism. downfalls of this is that good bacteria might be affected and antibiotic
resistance might develop
narrow-spectrum antibiotic
antibiotic that is effective against specific microbes. the organism causing the infection
must be known in order to use this type of antibiotic
What are the 4 ways bacteria can form resistance?
1. reduce the site of action-drug concentration by either pumping the drugs out or
preventing it from entering at the site of action
2. create an antagonist that works to block a site of action
, 3. alter the drug target to a shape that no longer allows the antibiotic to fit
4. inactivate the drug entirely
superinfection
secondary infection that is usually caused by an agent resistant to the treatment for the
primary infection
ex: pt is being treated for an ear infection but ends up getting a vaginal yeast infection
Clostridium difficile
C. diff; bacterial infection causing diarrhea and serious colon inflammation; common
after antibiotic use. C.diff is already in the gut but the good bacteria there keeps it from
proliferating. A broad-spectrum antibiotic might wipe out some of the gut's normal flora,
opening up the door for C.diff to take over
Methicillin-resistant Staphylococcus aureus
MRSA: resistant strain of bacteria that many common antibiotics cannot kill. It changes
penicillin-binding proteins, reducing affinity of the penicillins and cephalosporins to
target sites making them less effective. Requires strong antibiotics that do not depend
on the PBPs
amoxicillin
Amoxil: penicillin antibiotic. Can treat bacterial infections of respiratory tract, H. Pylori,
genitourinary, skin and skin structures. Does not treat MRSA
Birth control may not work as well when taking this drug
ADR:diarrhea, vaginal infection, headache
amoxicillin/clavulanate
Augmentin: penicillin combo, works to distract beta-lactamase enzyme (beta-lactamase
inhibitor) does not treat MRSA
ADR: diarrhea, candidiasis
Penicillin drugs
Drugs that bind to penicillin-binding proteins on bacterial membranes, weakening the
cell walls allowing them to burst, killing the bacteria.
Work well against gram positive bacteria
beta-lactam ring
AND ANSWERS BREAKDOWN
antimicrobial
able to destroy or suppress the growth of pathogens and other micro-organisms
gram positive
organism that stains purple under a microscope, lets us know that there are fewer
layers, meaning they are more susceptible to bacterial growth.
gram negative
organism that fails to color when stained and viewed under a microscope, meaning it
has extra layers of protection against bacteria
bacteriostatic
inhibits growth of bacteria, keep bacteria from replicating. Body's immune system
required to fully eliminate the infecting bacteria
bactericidal
antibiotics that kill bacteria directly. not always the better option because it can kill some
of the host's good bacteria as well. Body's immune system NOT required for bacterial
elimination. Often more toxic
broad-spectrum antibiotic
an antibiotic that is effective against a wide range of both gram-positive and gram-
negative bacteria. this is best when the provider is working against an unknown
organism. downfalls of this is that good bacteria might be affected and antibiotic
resistance might develop
narrow-spectrum antibiotic
antibiotic that is effective against specific microbes. the organism causing the infection
must be known in order to use this type of antibiotic
What are the 4 ways bacteria can form resistance?
1. reduce the site of action-drug concentration by either pumping the drugs out or
preventing it from entering at the site of action
2. create an antagonist that works to block a site of action
, 3. alter the drug target to a shape that no longer allows the antibiotic to fit
4. inactivate the drug entirely
superinfection
secondary infection that is usually caused by an agent resistant to the treatment for the
primary infection
ex: pt is being treated for an ear infection but ends up getting a vaginal yeast infection
Clostridium difficile
C. diff; bacterial infection causing diarrhea and serious colon inflammation; common
after antibiotic use. C.diff is already in the gut but the good bacteria there keeps it from
proliferating. A broad-spectrum antibiotic might wipe out some of the gut's normal flora,
opening up the door for C.diff to take over
Methicillin-resistant Staphylococcus aureus
MRSA: resistant strain of bacteria that many common antibiotics cannot kill. It changes
penicillin-binding proteins, reducing affinity of the penicillins and cephalosporins to
target sites making them less effective. Requires strong antibiotics that do not depend
on the PBPs
amoxicillin
Amoxil: penicillin antibiotic. Can treat bacterial infections of respiratory tract, H. Pylori,
genitourinary, skin and skin structures. Does not treat MRSA
Birth control may not work as well when taking this drug
ADR:diarrhea, vaginal infection, headache
amoxicillin/clavulanate
Augmentin: penicillin combo, works to distract beta-lactamase enzyme (beta-lactamase
inhibitor) does not treat MRSA
ADR: diarrhea, candidiasis
Penicillin drugs
Drugs that bind to penicillin-binding proteins on bacterial membranes, weakening the
cell walls allowing them to burst, killing the bacteria.
Work well against gram positive bacteria
beta-lactam ring
