USMLE Step 2 – High-Yield Antibiotics &
Treatments Overview | 2026 Exam-
Focused Infectious Disease &
Pharmacology Notes|| LATEST UPDATE!
Prophylaxis in HIV based on CD4 count (3 big ones) -CORRECTANSWER CD4 < 200
= ppx for PCP w/ bactrim
CD4 < 100 = ppx for toxo w/ double bactrim
CD4 < 50 = ppx for MAC w/ azithromycin
if cant use bactrim, use dapsone
if G6PD deficiency = use atovaquone
post-exposure prophylaxis following HIV exposure? -CORRECTANSWER Tenofovir
and Emtricitabine
Tx for disseminated MAC? -CORRECTANSWER clarithromycin and ethambutol (SE is
optic neuritis)
prophylaxis vs actual treatment of toxoplasmosis -CORRECTANSWER ppx is double
strength bactim
treatment is pyrimethamine and sulfadiazine for 6wks
,antibiotics for bacterial meningitis -CORRECTANSWER Vancomycin and Ceftriaxone
if young or old, give ampicillin to cover for listeria
antibiotics used for crypotoccal meningitis -CORRECTANSWER will be in an AIDS pt w/
CD4<200
IV Amphotericin and FLucytosine
tx for lyme disease?
what about lyme meningitis? -CORRECTANSWER lyme disease = doxycycline
if causes meningitis = Ceftriaxone
antibiotic treatment for cellulitis based on presentation -CORRECTANSWER if walk in
to office and not super sick: Cephalexin, Clindamycin, or Bactrim
if septic or inpatient = Vancomycin, linezolid
antibiotic treatment for clostridium perfringens (gas gangrene, crepitus, air in soft tissue
on xray) -CORRECTANSWER Clindamycin and penicillin
and rapid surgical debridment, especially if signs of NEC fascititis
, treatment of bronchitis vs CAP pneumonia vs hospital acquired pneumonia -
CORRECTANSWER bronchitis (productive cough, fever, neg CXR): first line is
azithromycin. Alt = Doxy or moxiflox
CAP: Azithromycin and Ceftriaxone (FQ is alt)
HAP: Vanc and Zosyn
Aspiration pneumonia or abscess is just like CAP: Ceftriazone and a macrolide
ATYPICAL/WALKING pneumonia is treated like bronchitis = azithromycin only
tx for CAP and Hospital acquired pneumonia -CORRECTANSWER CAP = azithromycin
and ceftriaxone
HAP = Vanc and zosyn
Tx of walking/atypical pneumonia -CORRECTANSWER tx like bronchitis: just
azithromycin
Doxyclycine or moxifloxacin are alternative
tx for gonorrhea and chlamydia -CORRECTANSWER gonorrhea = ceftriaxone IM 1
time
Treatments Overview | 2026 Exam-
Focused Infectious Disease &
Pharmacology Notes|| LATEST UPDATE!
Prophylaxis in HIV based on CD4 count (3 big ones) -CORRECTANSWER CD4 < 200
= ppx for PCP w/ bactrim
CD4 < 100 = ppx for toxo w/ double bactrim
CD4 < 50 = ppx for MAC w/ azithromycin
if cant use bactrim, use dapsone
if G6PD deficiency = use atovaquone
post-exposure prophylaxis following HIV exposure? -CORRECTANSWER Tenofovir
and Emtricitabine
Tx for disseminated MAC? -CORRECTANSWER clarithromycin and ethambutol (SE is
optic neuritis)
prophylaxis vs actual treatment of toxoplasmosis -CORRECTANSWER ppx is double
strength bactim
treatment is pyrimethamine and sulfadiazine for 6wks
,antibiotics for bacterial meningitis -CORRECTANSWER Vancomycin and Ceftriaxone
if young or old, give ampicillin to cover for listeria
antibiotics used for crypotoccal meningitis -CORRECTANSWER will be in an AIDS pt w/
CD4<200
IV Amphotericin and FLucytosine
tx for lyme disease?
what about lyme meningitis? -CORRECTANSWER lyme disease = doxycycline
if causes meningitis = Ceftriaxone
antibiotic treatment for cellulitis based on presentation -CORRECTANSWER if walk in
to office and not super sick: Cephalexin, Clindamycin, or Bactrim
if septic or inpatient = Vancomycin, linezolid
antibiotic treatment for clostridium perfringens (gas gangrene, crepitus, air in soft tissue
on xray) -CORRECTANSWER Clindamycin and penicillin
and rapid surgical debridment, especially if signs of NEC fascititis
, treatment of bronchitis vs CAP pneumonia vs hospital acquired pneumonia -
CORRECTANSWER bronchitis (productive cough, fever, neg CXR): first line is
azithromycin. Alt = Doxy or moxiflox
CAP: Azithromycin and Ceftriaxone (FQ is alt)
HAP: Vanc and Zosyn
Aspiration pneumonia or abscess is just like CAP: Ceftriazone and a macrolide
ATYPICAL/WALKING pneumonia is treated like bronchitis = azithromycin only
tx for CAP and Hospital acquired pneumonia -CORRECTANSWER CAP = azithromycin
and ceftriaxone
HAP = Vanc and zosyn
Tx of walking/atypical pneumonia -CORRECTANSWER tx like bronchitis: just
azithromycin
Doxyclycine or moxifloxacin are alternative
tx for gonorrhea and chlamydia -CORRECTANSWER gonorrhea = ceftriaxone IM 1
time
