Week 7 Flashcards
What class of antibiotics are responsible for causing discoloration and hypoplasia of teeth and bone?
tetracyclines
What class of antibiotics are responsible for preventing binding of tRNA to the mRNA by binding to the 30S subunit?
tetracyclines
This type of antibiotic is slowly degraded into nephrotoxic compounds in the container, so they shouldn’t be given to patients if over 6 months old.
tetracyclines
Which antibiotic was developed to combat resistant to tetracyclines?
Glycylcycline (Tigecycline)
Which class of antibiotics bind to the 30S ribosome subunit and distort its structure causing misreading of the mRNA?
aminoglycosides
What are some major side effects of aminoglycosides?
Ototoxicity (may be irreversible), nephrotoxicity, neuromuscular paralysis
Which class of antibiotics bind to the 50S subunit of ribosome and inhibits translocation steps of protein synthesis?
Macrolides
Which class of antibiotics is known for its drug-drug interactions with inhibition of CYP3A4 (grape juice)?
Macrolides
Which class of antibiotics is similar to macrolides, but its MOA is inhibiting RNA synthesis by RNA polymerases?
Macrocyclics (Fidaxomicin)
Which class of antibiotics is similar to macrolides and binds to 50S ribosome subunit and inhibits protein synthesis by blocking the polypeptide exit tunnel?
Lincosamides (clindamycin)
Which class of antibiotics bind to the bacterial 23S ribosomal RNA of the 50S subunit which inhibits the formation of the 70S initiation complex and translation of bacterial proteins?
Oxazolidinones (linezolid, tedizolid)
Which class of antibiotics inhibits both A & B subtypes of monoamine oxidase?
Oxazolidinones (linezolid, tedizolid)
Which class of antibiotics disrupts elongation and typically used in combination?
Streptogramins (dalfopristin/quinupristin)
Which class of antibiotics attacks the 50S ribosomal subunit and inhibits protein synthesis at the peptidyl transferase reaction?
Chloramphenicol
Which form of penicillin is orally administered and more stable in acidic conditions?
Penicillin V
Penicillin V is the oral form of penicillin and is more stable in acidic conditions. It is typically used for minor infections due to its poor bioavailability, narrow spectrum, and requirement of multiple daily dosing.
Which antibiotic is the standard therapy for primary, secondary, or early latent syphilis?
Penicillin G
A single dose of benzathine penicillin G is the standard therapy for primary, secondary, or early latent syphilis caused by the spirochete Treponema pallidum, providing low but persistent serum levels of penicillin.
What is the most common mechanism of antibiotic resistance in penicillin?
The most common mechanism of antibiotic resistance in penicillin is the production of beta-lactamases by bacteria, such as Staphylococcus aureus. These enzymes degrade the beta-lactam ring of penicillin, rendering them ineffective.
Which molecular structure makes the antibiotics nafcillin, oxacillin, methicillin, and dicloxacillin resistant to cleavage by bacterial beta-lactamases?
bulky R group
What are the antistaphylococcal penicillins?
Oxacillin, Nafcillin, Dicloxacillin (Methicillin)
Why are anti-staphylococcal penicillins not effective against MRSA?
Methicillin-resistant Staphylococcus aureus (MRSA) produces altered penicillin binding proteins that have a low affinity for binding beta-lactam antibiotics. This renders anti-staphylococcal penicillins ineffective.
For which bacterial infections is empiric treatment with nafcillin, oxacillin, or dicloxacillin most appropriate?
skin and soft tissue infections
Which of the following best describes the mechanism of action shared by the tazobactam and sulbactam?
Tazobactam and sulbactam inhibit bacterial β-lactamases. These drugs protect penicillin antibiotics from destruction by β-lactamases, enabling penicillin-based therapy for bacteria such as methicillin-sensitive Staph aureus.
When compared to other penicillins, piperacillin and ticarcillin have important additional indications due to activity against which of the following bacteria?
Pseudomonas species
Pseudomonas is a gram-negative aerobic bacteria that can cause a wide variety of serious infections, including pneumonia, urinary tract infection, and otitis externa. Piperacillin and ticarcillin are extended-spectrum penicillins, which unlike other penicillins, can be used to treat Pseudomonas infections.
What is the difference between the pharmacokinetic properties of the amino-penicillins amoxicillin and ampicillin?
The amino-penicillins, amoxicillin and ampicillin, have similar spectrums of activity, but amoxicillin has better oral bioavailability; a mnemonic is that aMOxacillin is administered by MOuth, and AMPicillin comes in AMPules. Amoxicillin is often given orally for common pediatric illness, including infections of the ear, sinuses, or throat. On the other hand, ampicillin is administered intravenously for more serious infections that require anaerobic coverage such as aspiration pneumonia.
Which of the following best describes the mechanism by which Enterococcus may become resistant to ampicillin?
Ampicillin-resistant strains of Enterococcus produce β-lactamase, which cleaves the β-lactam ring and prevents β-lactam antibiotics from blocking bacterial transpeptidase peptidoglycan cross-linking. Resistant Enterococcus infections may be treated with ampicillin plus sulbactam or with vancomycin.
What is a distinguishing feature of cephalosporin antibiotics in comparison to the penicillin antibiotic ampicillin?
They are resistant to penicillinase, but vulnerable to other beta-lactamases
Like ampicillin, cephalosporins are β-lactam antibiotics that bind penicillin binding protein (transpeptidase), preventing it from cross-linking peptidoglycan in the bacterial cell wall. However, while ampicillin is susceptible to β-lactamase (penicillinase), β-lactamases are ineffective against cephalosporins.
Aztreonam is most effective in treating infections caused by which of following pathogens?
gram negative aerobics
What is the primary treatment for Listeria monocytogenes?
Ampicillin
Vancomycin is an important antibiotic used to treat gram _____ bacterial infections.
positive
Vancomycin is often used as empiric treatment when methicillin-resistant Staphylococcus aureus (MRSA) is suspected. Vancomycin is not effective against gram negative organisms.
What is the mechanism of action of vancomycin?
Vancomycin is a glycopeptide antibiotic which obstruct the synthesis of bacterial cell walls. Vancomycin binds to the cell wall precursors D-alanine-D-alanine. By binding to these oligopeptides, vancomycin inhibits the synthesis of peptidoglycan necessary to make up the cell wall.
What is the difference between lipoglycopeptides and glycopeptide antibiotics?
lipoglycopeptides are more potent
Imipenem is administered as a broad spectrum antibiotic but it is easily degraded by the kidneys. What is administered alongside to prevent this?
Cilastatin
The lowest concentration of drug required to inhibit the growth of an organism.
Minimum inhibitory concentration
Why do you need to use a loading dose?
for rapid onset and establishment above MIC levels
This refers to the phenomenon where bacterial growth remains suppressed even after the concentration of an antibiotic has fallen below the minimum inhibitory concentration (MIC).
post-antibiotic effect
Acrosomal rxn
Fertilin and integrin are two molecular determinants involved in which process?
The fusion of sperm head and secondary oocyte membranes. It is also responsible for blocking polyspermy.
Which structure secretes hCG and what is its function?
syncytium and it maintains the corpus luteum
What happen to estrogen levels throughout pregancy?
Increases due to secretion of estrogen from placenta. Has roles in mammary gland development and myometrial growth (smooth muscle of the uterus)
Which protein expressed by the cytotrophoblasts allows the mother’s immune system to recognize the fetus as “self”?
HLA-G
What is the role of progesterone secreted by the placenta?
decreases myometrial excitability, maintains cervical mucus plug, increases development of secretory milk glands
What is the role of hCS?
like growth hormone
Early in pregnancy which hormones are responsible for inhibiting myometrial contractility?
progesterone and relaxin
Relaxin
Which hormone secreted by the placenta acts as the “placental clock”
CRH
Which hormones play an important role in the initiation and control of labor?
prostaglandins and leukotrienes
Pregnant women may experience mild fasting hypoglycemia and postprandial hyperglycemia and hyperinsulinemia due to what?
peripheral insulin resistance (cause of gestational diabetes)
What happens to LDL and HDL concentrations during pregnancy?
Increase due to effects of progesterone and estrogen, respectively
The physical act of a baby suckling at the breast sends nerve signals to the hypothalamus. This inhibits the release of ____ (which normally inhibits prolactin), thereby increasing prolactin secretion.
dopamine
This hormone is important for milk ejection and milk letdown. It can also be secreted due to other stimuli such as a crying baby
oxytocin
What is the MOA for fluoroquinolones?
inhibits DNA synthesis specifically blocking activity of DNA gyrase
What is the common suffix ending for the drugs which are part of the fluoroquinolone family?
-oxacin
“flock-of-oxen”
A patient being treated with fluoroquinolones for pneumonia is found to have an abnormal EKG. What is the most likely abnormality?
prolonged QT interval
Fluoroquinolones should be given a few hours before or after the ingestion of:
dairy (bc calcium, iron, and aluminium interact)
what is the mechanism of action for rifamycins
block RNA synthesis
What is the most common therapeutic use for rifampins?
tuberculosis (always used in combo w/ other drugs)
What is a major common side effect of rifampin use?
red/orange color to urine, sweat, tears
Sulfamethoxazole and trimethoprim combo is used to treat what type of infections?
UTIs
What is the MOA for Sulfamethoxazole and trimethoprim combo?
inhibits the tetrahydrofolic acid (THF) pathway
Metronidazole is effective against anaerobic bacteria and certain protozoan infections, including Giardia. However, it is not effective against _____.
aerobes
What is metronidazole’s mechanism of action?
Disrupts bacterial DNA
Metronidazole forms toxic free radical metabolites in the cell that disrupt bacterial DNA. This leads to bacterial cell death (metronidazole is bactericidal).
Ingesting _____ while receiving metronidazole therapy can trigger a disulfiram-like reaction, characterized by flushing, palpitations, nausea, and vomiting.
alcohol
What is the MOA for Mupirocin?
acts on gram-positive cocci and inhibits RNA and protein synthesis
What is the therapeutic use for Mupirocin?
topical application for impetigo (school sores)
What is Nitrofurantoin used to treat?
acute uncomplicated UTIs
What is the MOA for methenamine?
Methenamine works by breaking down into formaldehyde in acidic urine, which then kills bacteria and helps prevent urinary tract infections.
For a patient with chronic UTIs, what would you recommend medication wise?
methenamine
A pregnant woman experiences constipation and bloating. Which hormone can you attribute this to and why?
progesterone because it slows peristalsis and gastric emptying
Anemia is common in early pregnancy. Why is this and what should you recommend for the patient?
The body is starting to prepare for delivery and the possibility of blood loss. Hemoglobin levels don’t increase right away. Recommend iron supplement.
What pulmonary changes does a woman experience during pregnancy?
functional residual capacity/residual volume decreased due to uterus pushing up on diaphragm which pushes lungs
You are listening for murmurs in a pregnant patient. You hear a systolic murmur. Is this a normal finding?
Yes. Diastolic murmurs are NEVER normal!
Is lower back lordosis normal for a pregnant patient?
Yes, it is to accommodate the baby and to change center of gravity for balance.
Vast majority of inborn errors of metabolism are inherited in a ____ manner.
recessive
A biochemical test which measures enzyme activity in patient cells is considered a direct or indirect test?
direct
A biochemical test which measures levels of metabolites in blood via tandem mass spectrometry (MS/MS) is considered a direct or indirect test?
indirect
This indirect test allows for simultaneous identification of multiple compounds in a dried blood spot. It measures the products of enzyme activity in the circulation.
MS/MS
____ is performed on asymptomatic people NOT seeking medical care
screening
____ is performed in symptomatic people to establish or confirm a diagnosis
diagnostic testing
_____ is performed on asymptomatic people that had a positive screen in order to confirm or refute the positive result
diagnostic testing
What is the most common bacteria in the vagina and is it anaerobic and aerobic?
lactobacillus; gram-positive aerobic
Lactobacilli produce these two compounds which help to inhibit pathogenic processes.
lactic acid and H2O2
Name the condition in which there is an alteration in the composition of normal flora. Typically occurs when the anaerobic bacteria overtake the normal aerobic bacteria.
bacterial vaginosis
Anaerobes are linked to an increased incidence of what?
HIV
An increase in this bacteria is typically seen in bacterial vaginosis.
gardnerella vaginalis
This fungus is a part of the normal vaginal flora but can overgrow if the normal flora experiences a disruption
candida albicans
Fungal wall is made up of this compound.
chitin and ergosterol (cholesterol)
This hormone in oral contraceptive increases the risk of DVT.
estrogen
During 1st trimester, when trying to establish date of pregnancy using ultrasound, what is the most accurate measurement?
crown rump length
Definition of labor
cervical changes and uterine contractions
For a woman who has had a baby in the past, how long should she push until other measures should be taken?
<2 hours
Spider angiomas and nasal congestion/nose bleeds during pregnancy is attributed to which hormone?
estrogen
nausea and vomiting of pregnancy is attributed to which hormone?
hCG and estrogen
