Antibiotics Part 2 - Multidrug-Resistant Organisms & Specific Antibiotic Classes

Vocabulary flashcards covering multidrug-resistant organisms, key pharmacology concepts, aminoglycosides, quinolones, and miscellaneous antibiotics from the lecture notes.

Multidrug-Resistant Organisms

Organisms that are resistant to one or more classes of antimicrobial drugs.

MRSA

Methicillin-resistant Staphylococcus aureus; a multidrug-resistant organism that can be health-care associated or community acquired, posing a threat of becoming resistant to all currently available antibiotics.

VRE

Vancomycin-resistant enterococcus; a multidrug-resistant organism usually seen in urinary tract infections (UTIs).

ESBL

Extended-spectrum beta-lactamase; organisms resistant to all beta-lactam antibiotics and aztreonam, usually treated with carbapenems or sometimes quinolones.

CRE

Carbapenem-resistant Enterobacteriaceae; organisms resistant to carbapenems due to carbapenemase, requiring alternative treatments like tigecycline and colistimethate along with strict contact precautions and handwashing.

Minimum Inhibitory Concentration (MIC)

The lowest concentration of an antimicrobial drug required to inhibit the visible growth of a microorganism.

Peak Drug Level

The highest concentration of a drug in the patient's bloodstream, monitored during therapeutic drug monitoring to prevent toxicity.

Trough Drug Level

The lowest concentration of a drug in the patient's bloodstream, monitored to ensure adequate renal clearance of the drug and avoid toxicity.

Post-Antibiotic Effect

A period of continued bacterial growth suppression that persists after brief exposure to an antibiotic.

Synergistic Effect

An enhanced therapeutic outcome produced when two antibiotics given in combination produce an effect greater than the sum of their individual effects.

Therapeutic Drug Monitoring

The process of measuring serum peak and trough drug levels to maximize efficacy, maintain the minimum inhibitory concentration (MIC), and prevent toxicity.

Time-Dependent Killing

A property of certain antibiotics where prolonged exposure above the minimum inhibitory concentration (MIC) is required for maximum bacterial kill.

Aminoglycosides

A class of bactericidal antibiotics (including parenteral gentamicin and oral/rectal/topical neomycin) used against multidrug-resistant Gram-negative and some Gram-positive organisms, carrying key risks of nephrotoxicity and ototoxicity.

Gentamicin

A prototype aminoglycoside antibiotic administered parenterally for serious multidrug-resistant bacterial infections.

Neomycin

An aminoglycoside antibiotic administered orally, rectally, or topically; indicated for pre-op bowel preparation and hepatic encephalopathy.

Ciprofloxacin

A prototype bactericidal quinolone/fluoroquinolone antibiotic indicated for complicated infections, sexually transmitted infections, and anthrax.

Quinolones Black Box Warning

A major drug warning associated with quinolone antibiotics due to risks of tendonitis, ruptured tendons, and peripheral neuropathy.

Clindamycin

A miscellaneous antibiotic indicated for chronic bone, genitourinary, intraabdominal, and other serious infections; contraindicated in patients with $\text{age} < 1\text{ month}$ or ulcerative colitis/enteritis, with a major adverse effect of C. difficile infection.

Linezolid

A miscellaneous antibiotic indicated for VRE, MRSA, and healthcare-associated infections with excellent GI absorption suitable for prolonged outpatient therapy; interacts with vasopressors, SSRIs, and tyramine-containing foods.

Metronidazole

A miscellaneous antibiotic indicated for intraabdominal, gynecologic, and protozoal infections; contraindicated during the $\text{1st}$ trimester of pregnancy and requires avoiding alcohol from $24\text{ hr}$ prior to $36\text{ hr}$ post-administration.

Vancomycin

A bactericidal antibiotic reserved for resistant Gram-positive infections including MRSA and oral treatment for C. difficile or staph enteritis; requires serum drug level monitoring due to ototoxicity, nephrotoxicity, and Red Man Syndrome.

Red Man Syndrome

An adverse reaction from rapid vancomycin infusion characterized by fever/chills, hives, hypotension, tachycardia, nausea/vomiting, and a red rash on the neck/chest; managed by slowing the infusion to at least $1\text{ hour}$.