Infectious Diseases I & II Flashcards

Comprehensive vocabulary flashcards covering bacterial pathogens, antibiotic mechanisms, resistance patterns, and clinical treatment guidelines for infectious diseases.

Gram-positive bacteria

Organisms characterized by a thick cell wall that stain dark purple or blue.

Gram-negative bacteria

Organisms characterized by a thin cell wall that stain pink.

Atypical bacteria

Organisms that have no cell wall and do not stain (e.g., Legionella, Mycoplasma, and Chlamydophila).

Presence of infection (criteria)

Clinical signs including fever ($> 100.4^{\circ}F$), elevated WBC ($> 11,000\,\text{cells/mm}^3$), and site-specific symptoms like dysuria.

ESBL

Extended-spectrum beta-lactamase.

CRE

Carbapenem-resistant Enterobacterales.

VRE

Vancomycin-resistant Enterococcus.

Concentration-dependent killing

Dosing strategy where antibiotics like aminoglycosides are administered less frequently and in higher doses.

Time-dependent killing

Dosing strategy where antibiotics like beta-lactams are dosed more frequently or for longer durations (extended/continuous infusions) to stay above the MIC.

Bactericidal antibiotics

Antibiotics that kill bacteria, including cell wall inhibitors, cell membrane inhibitors, DNA/RNA inhibitors, and aminoglycosides.

Bacteriostatic antibiotics

Antibiotics that inhibit bacterial growth, including protein and folic acid synthesis inhibitors.

Hydrophilic antibiotics

Classes such as beta-lactams, vancomycin, and aminoglycosides that have small volumes of distribution, poor bioavailability, and are renally eliminated.

Lipophilic antibiotics

Classes such as quinolones, macrolides, and tetracyclines that have large volumes of distribution, excellent bioavailability (1:1 IV:PO), and hepatic elimination.

Penicillin G Benzathine (Bicillin L-A)

A natural penicillin administered IM only; IV administration can cause cardioresp arrest and death.

Antistaphylococcal Penicillins (e.g., Nafcillin, Oxacillin)

Antibiotics preferred for MSSA soft tissue, bone, joint, and bloodstream infections that do not require renal dose adjustments.

Aminopenicillins (e.g., Amoxicillin, Ampicillin)

Antibiotics covering Streptococci, Enterococci, and HNPEK; Amoxicillin is first-line for acute otitis media ($90\,mg/kg/day$).

Piperacillin/Tazobactam (Zosyn)

The only penicillin with Pseudomonas coverage; typically administered via extended 4-hour infusions.

1st Generation Cephalosporins (e.g., Cephalexin, Cefazolin)

Cephalosporins covering Gram-positive cocci (Strep, MSSA) and PEK; Cefazolin is used for surgical prophylaxis.

2nd Generation Cephalosporins (e.g., Cefotetan, Cefoxitin)

Cephalosporins with added anaerobic coverage (B. fragilis) often used for GI surgery prophylaxis; Cefotetan can cause disulfiram-like reactions.

3rd Generation Cephalosporins (e.g., Ceftriaxone, Ceftazidime)

Ceftriaxone is used for meningitis and CAP; Ceftazidime (Fortaz) has Pseudomonas activity but no Gram-positive activity.

4th Generation Cephalosporin (Cefepime)

A broad-spectrum antibiotic covering HNPEK, CAPES, Pseudomonas, and Gram-positives.

5th Generation Cephalosporin (Ceftaroline fosamil)

The only cephalosporin with activity against MRSA.

Ceftriaxone Contraindications

Should not be used in hyperbilirubinemic neonates or with Calcium-containing IV fluids in neonates < 28 days due to risk of biliary sludging.

Ertapenem (Invanz)

A carbapenem that lacks coverage against Pseudomonas, Acinetobacter, or Enterococcus (PEA).

Aztreonam (Azactam)

A monobactam with Gram-negative coverage only (including Pseudomonas) that has no cross-reactivity with penicillin allergies.

Aminoglycosides (Side Effects)

Major boxed warnings include nephrotoxicity, ototoxicity, and neuromuscular blockade; requires monitoring of peak and trough levels.

Gentamicin/Tobramycin Traditional Dosing

$1-2.5\,mg/kg/dose$ with a goal trough of $< 2\,\mu g/mL$ ($< 1\,\mu g/mL$ for synergy).

Quinolones (Mechanism of Action)

Antibiotics that inhibit bacterial DNA topoisomerase IV and DNA gyrase.

Quinolone Black Box Warnings

Tendon inflammation and rupture, peripheral neuropathy, and CNS effects (seizures, tremor, suicidality).

Respiratory Quinolones

Levofloxacin and Moxifloxacin; specifically used for S. pneumoniae and atypicals in CAP.

Moxifloxacin (Avelox)

The only quinolone that cannot be used to treat UTIs.

Macrolides (e.g., Azithromycin, Clarithromycin)

Antibiotics with excellent atypical coverage (Legionella, Mycoplasma, Chlamydia); warnings include QT prolongation and hepatotoxicity.

Tetracyclines (Contraindications)

Avoid in children < 8 years old, pregnancy, and breastfeeding due to tooth discoloration and skeletal development suppression.

SMX/TMP (Bactrim) Warnings

Sulfa allergy, SJS/TEN, thrombotic purpura, and hyperkalemia; compatible with D5W only.

Vancomycin (Vancocin)

First-line IV treatment for MRSA; requires AUC/MIC ratio monitoring (goal 400-600) and can cause infusion reactions ('Red Man Syndrome').

Daptomycin (Cubicin)

A cyclic lipopeptide used for MRSA and VRE; should NOT be used for pneumonia as it is inactivated by lung surfactant.

Linezolid (Zyvox)

An oxazolidinone covering MRSA and VRE; warnings include myelosuppression (thrombocytopenia), serotonin syndrome, and optic neuropathy.

Quinupristin/Dalfopristin (Synercid)

A medication used for VRE (E. faecium) that is poorly tolerated and requires a central line to prevent phlebitis.

Tigecycline (Tygacil)

A broad-spectrum antibiotic with a BBW for increased risk of death; has no activity against the '3 Ps' (Pseudomonas, Proteus, Providencia).

Clindamycin (Cleocin)

A lincosamide with a BBW for C. diff colitis; requires an induction test (D-test) if S. aureus is resistant to erythromycin.

Metronidazole (Flagyl)

An anaerobic and protozoal agent; contraindicated with alcohol due to disulfiram-like reactions and causes a metallic taste.

Nitrofurantoin (Macrobid)

Drug of choice for uncomplicated cystitis; contraindicated in patients with CrCl $< 60\,mL/min$.

Meningitis Empiric Treatment (Neonates)

Ampicillin (for Listeria) plus Cefotaxime or Gentamicin.

Meningitis Empiric Treatment (> 50y or Immunocompromised)

Ampicillin (for Listeria) plus Ceftriaxone (or Cefotaxime) plus Vancomycin.

Active Tuberculosis Treatment (RIPE)

Intensive phase for 2 months consisting of Rifampin, Isoniazid, Pyrazinamide, and Ethambutol.

Isoniazid (INH) Side Effects

Boxed warning for hepatitis and known to cause peripheral neuropathy (mitigated with Vitamin B6/pyridoxine).

Infective Endocarditis Dental Prophylaxis

Amoxicillin $2\,g$ PO once (30-60 mins before procedure); if allergic to penicillin, use Azithromycin ($500\,mg$) or Doxycycline ($100\,mg$).

Syphilis (Primary/Secondary) Treatment

Penicillin G Benzathine (Bicillin L-A) $2.4\,\text{million units}$ IM x 1.