Snapshot A 48-year-old woman presents to the urgent care clinic after finding a tick on her leg. She had recently gone camping in New England. She pulled off the tick on her own but was not able to show the tick to the physician. She denies having any rashes or symptoms. However, she is concerned about Lyme disease. She is given the first-line treatment for Lyme disease and reassured. She is advised to wear sunscreen or avoid the sun while on this treatment. (Lyme disease) Introduction Drugs tetracycline doxycycline minocycline Mechanism of action reversibly binds to the bacterial ribosomal 30S subunit, inhibiting the elongation phase of RNA synthesis by preventing the attachment of aminoacyl tRNA to mRNA acceptor site accumulates inside bacterial cells, making it good for intracellular agents bacteriostatic absorption inhibited by milk and antacids eliminated via stool Mechanism of resistance bacterial transport pumps will prevent accumulation of drug inside the cell by increasing efflux out or decreasing uptake of the drug Clinical use infections gram-positive aerobes gram-negative rods spirochetes atypical respiratory pathogens Mycoplasma Legionella Chlamydophila anaerobes tick-mediated infections dermatologic conditions acne rosacea no activity against Pseudomonas high-yield uses doxycycline is used for Chlamydia trachomatis tick-borne infections (Rickettsia, Borrelia, Ehrlichia, and Anaplasma) Adverse effects gastrointestinal upset (most common) discoloration of teeth inhibition of bone growth in children photosensitive rash teratogenic and contraindicated in pregnancy
QUESTIONS 1 of 2 1 2 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.MC.14.1) A 45-year-old female presents to her family medicine physician complaining of fever for 2.5 weeks, enlarged lymph nodes in her right axilla, and a small bump that formed when her recently adopted cat bit her 3 weeks ago. Based on her symptoms and history, the physician prescribed an antiobitic to treat her current illness. Several days later, she experienced erythema and itchiness on her shoulders, arms, and back after spending only several minutes a day in the sun (Figure A). Which of the following is the mechanism of action of the antibiotic prescribed? Tested Concept QID: 106430 FIGURES: A Type & Select Correct Answer 1 Blocks the peptidyltransferase on the 50S ribosomal subunit 14% (7/50) 2 Forms toxic free radicals that damage DNA 8% (4/50) 3 Binds to the 30S ribosomal subunit preventing aminoacl-tRNA attachment 56% (28/50) 4 Binds to PBP3 preventing the cross-linking of the peptidoglycan layer 8% (4/50) 5 Blocks peptide translocation by binding to the 23S rRNA of the 50S ribosomal subunit 8% (4/50) L 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review tested concept