ULTIMATE CRAM

SID 02: MENINGITIS

🧠 1. ANATOMY & CSF BASICS

Meningitis =

Inflammation between pia + arachnoid (subarachnoid space = CSF lives here)

Normal CSF:

Clear
WBC < 5
Glucose = 1/2–2/3 serum
Protein < 0.4 g/L
Opening pressure 10–20 cm H₂O

🔥 2. CLASSIC BACTERIAL MENINGITIS CSF

If you see this → it’s bacterial:

⬆ Opening pressure
⬇ Glucose
⬆ Protein
⬆ WBC (NEUTROPHILS)
CSF:Serum glucose < 0.3
Cloudy

💡 Monocytes → think Listeria
💡 Lymphocytes → think viral

👶 3. AGE = ORGANISM

Neonates (<1 month)

GBS
E. coli
Listeria

Empiric =
Ampicillin + Cefotaxime

1 month – 50 years

S. pneumoniae
N. meningitidis

Empiric =
Ceftriaxone or Cefotaxime

(Add Vanco if high PRSP rates)

>50 years

Add LISTERIA coverage.

Empiric =
Ceftriaxone + Ampicillin

Post-op / head trauma / CSF shunt

Staph aureus
Staph epidermidis
Pseudomonas

Empiric =
Meropenem + Vancomycin
OR
Cefepime + Vancomycin

💡 ALWAYS add vanco here

🧬 4. TARGETED THERAPY HIGH YIELD

S. pneumoniae

Pen sensitive → Pen G or Ampicillin
Pen resistant → Ceftriaxone + Vanco
Duration: 10–14 days

N. meningitidis

Penicillin G
Duration: 5–7 days

Petechial rash classic

H. influenzae

Beta-lactamase + → 3rd gen ceph
Duration: 7–10 days

Listeria

Ampicillin
Duration: 14–21 days

(TMP-SMX if pen allergic)

MSSA

Cloxacillin

MRSA

Vancomycin

💊 5. DEXAMETHASONE

Dose:
0.15 mg/kg IV q6h (max 10 mg)
for 2–4 days

Timing:
⚠ BEFORE or WITH first antibiotic dose
(max 4 hours after)

Best evidence:
Children + S. pneumoniae

🚨 6. PROPHYLAXIS

N. meningitidis close contacts:

Rifampin 600 mg PO BID x 4 doses
OR
Ceftriaxone 250 mg IM once

(Cipro no longer recommended)

H. influenzae contacts:

Rifampin 600 mg PO daily x 4 days

💉 7. VACCINES – HIGH YIELD

Hib

2, 4, 6, 18 months

Men C

2 + 12 months

Men B

Close contacts
High risk
Military
Travelers

Quadrivalent (A,C,Y,W)

Grade 9
High risk
Travelers

PCV20

All kids
Age 65+
High risk (asplenia, HIV, immunosuppressed, etc.)

🧠 8. PENETRATION RULES

Better penetration when:

Inflamed meninges
Small MW
Lipophilic
Low protein binding
Unionized

Worse activity when:

Low pH
High protein
High temperature

⚡ 9. MOST TESTED TRAPS

50 years = ADD AMPICILLIN

Post-op = ADD VANCO
Monocytes = LISTERIA
Petechial rash = MENINGOCOCCAL
LP contraindicated with papilledema
Dexamethasone timing is CRITICAL
N. meningitidis duration = 5–7 days

🧠 10. CLASSIC TRIAD

Fever
Headache
Nuchal rigidity

(95% have at least 2 of 4: fever, headache, stiff neck, AMS)

SID 03A: Line Infections

💉 CRBSI (Catheter Related Bloodstream Infection)

🔥 5-Minute Master Sheet

🧠 1⃣ Risk Factors

👤 Patient

Bone marrow transplant
Immunodeficiency / neutropenia
Malnutrition
Parenteral nutrition (TPN 🚨)
Previous BSI
Extremes of age
Loss of skin integrity
ICU admission (kids with GI disease/cancer)

🧵 Catheter

Femoral site (WORST) 🚨
No maximal barrier precautions
Poor site care
Long duration
Hemodialysis use
Bare catheter (not antibiotic-impregnated)

🏆 Best site = Subclavian

🚫 Worst site = Femoral

⏳ 2⃣ Ideal Catheter Durations

Peripheral < 4 days
Central venous < 6 days
Arterial < 4–6 days
PICC / surgically inserted → weeks–months

If longer → infection risk climbs.

🦠 3⃣ Pathophysiology

🔥 MOST COMMON = Skin colonization

Biofilm = fibrinogen + fibrin + bacterial glycocalyx

Other:

Hematogenous seeding (often GI source)
Infusate contamination (rare, epidemic)

If exam asks “most common mechanism” → SKIN.

🧫 4⃣ Likely Pathogens

🟣 Majority (70–85%) = Gram positive

CoNS (most common)
Staph aureus
Enterococcus
Streptococcus

🔵 Gram negative (15–30%)

E. coli
Klebsiella
Pseudomonas
Enterobacter
Serratia
Acinetobacter

🟡 Candida = 13–25%

High risk with:

TPN
Broad antibiotics
Transplant
Femoral line

🌡 5⃣ Clinical Criteria (Adults)

Temp > 38°C
Hypotension
Tachycardia
Purulence at site
Positive blood culture
No other source
Has vascular catheter

Infants:

Fever OR hypothermia
Apnea
Bradycardia

🚫 6⃣ DO NOT TREAT If:

Positive catheter tip culture only
Catheter positive, peripheral negative
Phlebitis without systemic infection

💊 7⃣ Empiric Therapy Logic

Gram positive → VANCOMYCIN

Because:

CoNS often resistant to cloxacillin & cefazolin
Covers MRSA

Gram negative

Immunocompromised?
→ Meropenem or Imipenem

Other?
→ Ceftriaxone or Cefotaxime

🎯 8⃣ Definitive Gram Positive Therapy

Vancomycin
Cefazolin
Cloxacillin
Daptomycin (resistant only)
Linezolid (resistant only)

⏳ 9⃣ Duration

🧠 START counting AFTER FIRST NEGATIVE BLOOD CULTURE

7–14 days
14 days minimum if Staph aureus

Longer if:

Endocarditis
Foreign material
Metastatic infection

🗑 🔥 10⃣ REMOVE THE LINE IF:

Severe sepsis / shock
Hemodynamic instability
Pus/swelling at site
Persistent bacteremia > 72 hrs
Short-term catheter with:
- Staph aureus
- Enterococci
- Gram negative bacilli
- Fungi
- Mycobacteria
Long-term catheter with:
- Staph aureus
- Pseudomonas
- Fungi
- Mycobacteria

If possible → REMOVE THE LINE.

🔒 11⃣ Antibiotic Lock Therapy

Use only if catheter cannot be removed AND:

CoNS
Non-resistant gram negative

🚫 NEVER for:

Staph aureus
Pseudomonas
Candida
Resistant GNB

Lock solutions:

Gentamicin + heparin
Vancomycin + heparin
Cefazolin + heparin

📊 12⃣ Monitoring

Routine:

Vitals q4H
Temp q4H
LOC q4H
IV site q4H
WBC daily
Blood cultures daily until negative x2

Drug-specific:

Vanco levels
Vancomycin infusion syndrome
SCr 2–3x/week
Urine output
Rash
Bowel movements

🚨 EXAM TRAPS TO REMEMBER

Duration starts after FIRST NEGATIVE culture
CoNS = most common
Femoral = highest risk
Subclavian = lowest risk
Vancomycin is empiric gram positive
Antibiotic lock NEVER for Candida or S aureus
Persistent bacteremia >72 hrs → remove

SID 03B: SEPSIS

🧠 SEPSIS CORE CONCEPTS

✅ Definition

Sepsis = Life-threatening organ dysfunction caused by a dysregulated host response to infection.

Septic Shock = Sepsis + persistent hypotension despite adequate IV fluids → requires vasopressors.

🚨 SIGNS & SYMPTOMS

Think: ↑ HR, ↑ RR, ↓ BP, ↑/↓ Temp, ↑/↓ WBC

Temp <36 or >38
HR >90
RR >20
SBP ≤100
Confusion / ↓ LOC
↓ urine output
Lactate elevation

🧮 SCORING

qSOFA (≥2 = organ dysfunction)

RR ≥22
SBP ≤100
Altered mental status

NEWS ≥5 = flag for septic shock

💧 MANAGEMENT (ORDER MATTERS)

1⃣ Medical emergency
2⃣ Fluids: 0.9% NS 30 mL/kg initially

May repeat up to 60 mL/kg total
3⃣ Cultures BEFORE antibiotics (if possible)
4⃣ IV antibiotics within 1 hour
Each 1-hour delay → ↑ mortality by 8%
5⃣ If still hypotensive → VASOPRESSORS

🦠 SITE → BUG → DRUG

🧠 CNS

Bugs

Strep pneumoniae (G+)
H. influenzae (G-)
Neisseria meningitidis (G-)

Empiric

Ceftriaxone 2 g IV q12h

Why q12h? → BBB → need higher sustained CSF levels.

🫁 PNEUMONIA

Bugs

Strep pneumo (G+)
H flu (G-)
Mycoplasma, Chlamydia (atypical)

Empiric

Ceftriaxone 2 g IV q24h

Azithromycin 500 mg daily (or doxy)
OR

Moxifloxacin 400 mg daily

🫀 ENDOCARDITIS

Bugs

Staph aureus (G+)
Viridans strep (G+)

Empiric

Ceftriaxone 2 g IV q24h

Vancomycin 30 mg/kg IV loading
→ then 15 mg/kg q8–12h

Why loading? → Rapid therapeutic levels (vegetations, high mortality).

🍽 INTRA-ABDOMINAL

Bugs

E. coli (G-)
Klebsiella (G-)
Bacteroides fragilis (ANAEROBE)
Enterococcus

Empiric

Ceftriaxone 2 g IV q24h

Metronidazole 500 mg q12h
OR

Cefazolin + Metronidazole

Metro = ANAEROBE coverage.

🚽 URINARY TRACT (Sepsis)

Bugs

Gram negative rods
ESBL risk

Empiric

Meropenem 500 mg IV q6h

Why?

Severe sepsis → broad
ESBL coverage
Strong bactericidal

🩹 SSTI

Bugs

MSSA
Strep pyogenes
CoNS (less common)

Empiric

Cefazolin 2 g IV q8h
If MRSA suspected → Vancomycin 15 mg/kg q12h

💉 IV LINE

Bugs

CoNS (high resistance)
Staph aureus
Strep

Empiric

Vancomycin 15 mg/kg q12h

Why not cefazolin?
CoNS often resistant to beta-lactams.

❓ UNKNOWN SOURCE + SEVERE

Meropenem 500 mg q6h

Vancomycin 15 mg/kg q12h
(especially if septic shock or MRSA risk)

🔬 GRAM INSTINCT REFRESH

Gram Positive

Staph
Strep
Enterococcus

Gram Negative

E. coli
Klebsiella
Proteus
Enterobacter
Pseudomonas
H. influenzae

Atypical

Mycoplasma
Chlamydia
Legionella

🎯 FINAL RAPID MEMORY HOOKS

CNS = q12h (BBB)
Pneumonia = + azithro (atypicals)
Endocarditis = vanco loading
Abdomen = add metro (anaerobes)
Urine = carbapenem if sick
IV line = vanco (CoNS resistant)

SID 09: ADULT IMMUNIZATIONS

🫁 INFLUENZA (≥65 = HUGE EXAM AREA)

📊 BURDEN

≥65 = 15% population
But:
- 70% hospitalizations
- >90% deaths

🫀 Risk Multiplier

5× ↑ death → chronic heart disease
12× ↑ death → chronic lung disease
20× ↑ death → BOTH

💉 NACI ≥65 Prefers:

IIV3-Adj
IIV-HD
RIV

📈 High Dose Trial

24.2% more efficacious
↓ 6.9% all-cause hospitalization
↓ 39.8% serious pneumonia
↓ 17.7% serious cardio-respiratory events

🧨 HERPES ZOSTER (SHINGLES)

📌 Risk

Prior VZV (natural or vaccine)
Immunocompromised
Cancer, HIV, transplant
Steroids

⚡ PHN

Pain >90 days
Worse in:
50
- Females
- Severe rash
- Severe acute pain

💉 RZV (Shingrix)

≥50 years
2 doses (2–6 months)
Even if prior Zostavax or shingles
97% efficacy
NOT publicly funded in BC

🦠 PNEUMOCOCCAL

Disease Types

Invasive
Non-invasive (mucosal)
Pneumonia ± bacteremia

Risk Factors

HIV
Chronic lung/heart disease
Diabetes
Smoking
Alcoholism
Asplenia
Immunocompromised
CKD

🆕 2025 Update

PCV20 or PCV21
- All ≥65
- ≥18 with risk factors
If previously got PCV13/15/PPSV23:
- Give PCV20/21 after ≥1 year
- Then done

👶 TDAP

1 dose in adulthood
Td booster q10 years
Every pregnancy (27–32 weeks)
Maternal VE in infants <3 months = 91%

🧪 HEPATITIS

🅱 Hep B

DNA virus
Blood, sexual, perinatal
Schedule: 0, 1, 6 months
NOT publicly funded for travel

🅰 Hep A

RNA virus
Fecal-oral
Travel-related
95–100% seroconversion
NOT publicly funded for travel

🐶 RABIES (PRE-EXPOSURE)

Who?

Vets
Lab/wildlife workers
Cave explorers
Long-term travelers to endemic areas

High Risk Schedule

3 doses (0, 7, 21–28)
Booster if Ab < 0.5 IU/mL

💧 CHOLERA (DUKORAL)

Protects against:
- Vibrio O1
- Short-term ETEC
2 doses
85% → ~50% by year 2
Limited benefit
NOT publicly funded in BC

🌍 TYPHOID

💉 Typh-I (IM)

≥2 years
Single dose 0.5 mL IM
Re-dose q3 years
55% efficacy

💊 Typh-O (Oral)

≥5 years
4 capsules alternate days
Re-dose q7 years
Contraindicated in:
- Immunocompromised
- Pregnant
- Acute GI / IBD

💊 TYPHOID TREATMENT

Susceptible:

Ciprofloxacin 500 mg BID 7–10 days

MDR:

Azithromycin
Ceftriaxone

XDR:

Carbapenem (meropenem)

🧠 HALO APPROACH (EXAM KEYWORD)

Health Conditions
Age
Lifestyle
Occupation

🚨 PUBLIC FUNDING (BC EXAM TRAP)

NOT publicly funded for travel:

Hep A
Hep B
Rabies
Cholera
Typhoid
Shingrix

🏁 FINAL MEMORY HOOKS

≥65 = FLU & PNEUMO = HUGE
Shingles = 97%
Tdap pregnancy = 27–32 weeks
Rabies booster <0.5 IU/mL
Typhoid IM = q3 yrs, Oral = q7 yrs
PCV20/21 = done

SID 04: INFECTIVE ENDOCARDITIS

1⃣ What Is It?

Infection of the endocardial surface of the heart
→ usually heart valves
→ formation of vegetations (platelet + fibrin + bacteria)

2⃣ Epidemiology – Who Gets It?

🔹 IV drug use
🔹 Prosthetic valves
🔹 Congenital heart disease
🔹 Prior IE
🔹 Central lines
🔹 Hemodialysis
🔹 Degenerative valve disease (older adults)

Native valve → most common overall
Prosthetic valve → higher complication rate

3⃣ Pathogenesis (VERY TESTABLE)

Step 1⃣ Endothelial damage
• turbulent blood flow
• abnormal valves
• prosthetic material

Step 2⃣ Platelet + fibrin deposition
→ sterile vegetation forms

Step 3⃣ Bacteremia
→ bacteria adhere to vegetation

Step 4⃣ Vegetation growth
→ bacteria + fibrin shield
→ immune system cannot penetrate

Why Are Vegetations Hard To Treat?

• High bacterial burden
• Poor blood supply
• Low metabolic activity
• Biofilm formation (prosthetic valves)
• Immune evasion

4⃣ Microbiology Patterns

Native Valve (most common overall)

👉 Staphylococcus aureus

Also:
• Strep viridans
• Enterococcus

Prosthetic Valve

Early (< 60 days):
👉 CoNS
👉 S. aureus

Late:
👉 Similar to native (strep, enterococcus)

IVDU

👉 S. aureus
👉 Tricuspid valve

HACEK

Gram-negative fastidious organisms
Oral flora
Cause subacute IE

5⃣ Clinical Presentation

Classic Triad:

• Fever
• New murmur
• Positive blood cultures

But not always all 3.

Peripheral Stigmata (LOVE TO TEST THESE)

Immune complex:
• Osler nodes (painful)
• Roth spots

Vascular:
• Janeway lesions (painless)
• Splinter hemorrhages

Embolic:
• Stroke
• Splenic infarct
• Septic pulmonary emboli (right-sided IE)

6⃣ Duke Criteria (HIGH YIELD)

Major Criteria

• Positive blood cultures (typical organism, 2 separate cultures)
• Evidence of endocardial involvement on echo
• New valvular regurgitation

Minor Criteria

• Fever
• Predisposing heart condition
• Vascular phenomena
• Immunologic phenomena
• Positive blood culture not meeting major

Definite IE =

• 2 major
OR
• 1 major + 3 minor
OR
• 5 minor

7⃣ Complications

💥 Embolic events
• Stroke
• Splenic infarct
• Septic pulmonary emboli

💥 Cardiac
• Heart failure (most common cause of death)
• Valve perforation
• Abscess

💥 Immune mediated
• Glomerulonephritis

8⃣ When To Call Surgery

• Heart failure
• Persistent bacteremia
• Large vegetations
• Recurrent emboli
• Valve perforation
• Abscess

9⃣ Blood Cultures

• Always draw BEFORE antibiotics
• 3 sets from different sites
• Duration clock starts from FIRST negative culture

🔟 Right vs Left-Sided IE

Left-sided:
• Systemic emboli
• Stroke

Right-sided:
• Septic pulmonary emboli
• IVDU common

🧠 Pattern Memory Trick

If you see:
• IVDU → think tricuspid → S. aureus
• Prosthetic valve → think CoNS + biofilm
• Subacute slow course → think viridans
• Rapid destructive course → think S. aureus

🚨 Exam Trap Reminders

• New regurgitation = MAJOR criteria
• Fever alone = minor
• CoNS = prosthetic
• Viridans = dental/oral
• Vegetations = platelet + fibrin + bacteria
• Duration counts from first negative culture
• Heart failure = most common cause of death

🧠 STEP 1: Identify the Organism

Viridans / Oral strep → MIC based
Enterococcus → synergy required
Staph aureus → anatomy based
Staph epi → prosthetic = triple therapy

🟠 VIRIDANS / ORAL STREP

MIC ≤ 0.12 (Highly susceptible)

Native Valve

Uncomplicated
<65 yrs
Normal renal + hearing

👉 2-week short course
Penicillin G 12–18 MU/day IV
OR Ceftriaxone 2 g IV daily

Gentamicin 3 mg/kg IV daily
🕒 Duration: 2 weeks total

If ≥65 or ↓ renal or hearing
👉 NO short course
Penicillin G 12–18 MU/day IV x 4 weeks
OR Ceftriaxone 2 g IV daily x 4 weeks

Prosthetic Valve

Penicillin G 24 MU/day IV x 6 weeks
OR Ceftriaxone 2 g IV daily x 6 weeks

Gentamicin 3 mg/kg daily x 2 weeks

🔑 If MIC > 0.12 → gent x 6 weeks

MIC 0.12–0.5 (Intermediate)

Native valve
Penicillin G 24 MU/day IV

Gentamicin 3 mg/kg daily
🕒 4–6 weeks (often 6 if intermediate)

MIC ≥ 0.5 (Resistant)

Treat as resistant
🕒 6 weeks total therapy

🔵 ENTEROCOCCUS

⚠ ALWAYS requires combination therapy
Monotherapy = fail

Susceptible to Penicillin + Gentamicin

Penicillin G 18–30 MU/day IV
OR Ampicillin 2 g IV q4h

Gentamicin 1 mg/kg IV q8h

🕒 4–6 weeks

CrCl <50 OR 8th nerve dysfunction

👉 Avoid gent

Ampicillin 2 g IV q4h

Ceftriaxone 2 g IV q12h
🕒 6 weeks

(Double beta-lactam synergy)

Gentamicin Resistant

Ampicillin 2 g IV q4h

Ceftriaxone 2 g IV q12h
🕒 6 weeks

Penicillin Resistant

Vancomycin 15 mg/kg IV q12h

Gentamicin 1 mg/kg q8h
🕒 6 weeks

🔴 STAPH AUREUS (ANATOMY BASED)

MSSA

Left-sided (Mitral / Aortic)

Cloxacillin 2 g IV q4h
🕒 6 weeks

Right-sided Uncomplicated (IVDU)

Cloxacillin 2 g IV q4h
🕒 2 weeks

Right-sided Complicated

Cloxacillin 2 g IV q4h
🕒 6 weeks

Prosthetic Valve MSSA

Triple Therapy:

Cloxacillin 2 g IV q4h ≥6 weeks

Gentamicin 1 mg/kg q8h x 2 weeks
Rifampin 300 mg PO TID ≥6 weeks

⚠ Start rifampin 3–5 days after vanco/gent

MRSA (Native)

Vancomycin 15 mg/kg IV q12h
🕒 6 weeks

If vanco intolerant → Daptomycin 8–10 mg/kg daily

🟣 STAPH EPIDERMIDIS (Prosthetic)

Always treat like prosthetic staph:

Vancomycin 15 mg/kg IV q12h ≥6 weeks

Gentamicin 1 mg/kg q8h x 2 weeks
Rifampin 300 mg PO TID ≥6 weeks

Rifampin delayed 3–5 days

🧠 GENTAMICIN RULES

Used for synergy
Duration often 2 weeks (prosthetic staph + viridans prosthetic)
4–6 weeks in enterococcus (unless double beta-lactam used)
Peak ~3 mg/L
Trough <1 mg/L

🧠 PENICILLIN DOSING MEMORY

Viridans susceptible → 12–18 MU/day
Viridans intermediate/resistant → 24 MU/day
Enterococcus → 18–30 MU/day

Prosthetic = usually 6 weeks

🧠 RIFAMPIN RULES

Only for prosthetic staph
300 mg PO TID
Delayed start 3–5 days
Never monotherapy
Biofilm penetration

🧠 DURATION PATTERNS

2 weeks → right-sided uncomplicated MSSA OR short-course viridans
4 weeks → native viridans susceptible
6 weeks → prosthetic OR resistant OR enterococcus OR left-sided staph

When in doubt → 6 weeks

🚨 EXAM TRAPS

• Gentamicin duration differs depending on organism
• MIC determines viridans duration
• Enterococcus never monotherapy
• Prosthetic staph = triple therapy
• Rifampin delayed
• Right-sided uncomplicated staph = only 2 weeks

🧠 THE MASTER FLOW

If IVDU + tricuspid + MSSA → 2 weeks clox

If prosthetic + staph → triple therapy

If viridans → check MIC

If enterococcus → combo therapy mandatory

If resistant or unsure → 6 weeks

SID 07: THERAPEUTICS OF INFECTIONS W/ MULTI DRUG RESISTANT ORGANISMS

1⃣ What is MRSA?

Staphylococcus aureus

Gram-positive cocci
Catalase +
Coagulase +
Clusters on Gram stain
Normal flora: nares, skin, GI tract
Forms biofilm on devices
Produces exotoxins

2⃣ MRSA Resistance Mechanism (VERY TESTABLE)

mecA gene → PBP2a

PBP2a:

Altered penicillin-binding protein
↓ affinity for beta-lactams
Cell wall synthesis continues despite beta-lactam exposure

🔑 Oxacillin resistance = resistant to ALL standard beta-lactams
EXCEPTION → 5th gen cephalosporins (ceftaroline, ceftobiprole)

🧠 MEMORY ANCHOR:
mecA = “Makes beta-lactams useless”

3⃣ MRSA RISK FACTORS

Recent hospitalization
Surgery
LTC facility
Indwelling devices
Hemodialysis
Broad-spectrum antibiotics
IVDU
Close-contact environments
Skin trauma

Common infection sites:

SSTI (most common)
Bacteremia
Endocarditis
Pneumonia
Bone & joint

4⃣ VANCOMYCIN (GOLD STANDARD)

MOA

Binds D-Ala-D-Ala
Prevents cell wall elongation
Bactericidal
Time-dependent killing

Dosing (NORMAL RENAL)

Loading: 20 mg/kg IV x1
Maintenance: 15 mg/kg IV q8–12h

TDM:
Target trough 10–15 mg/L
Or AUC/MIC monitoring

Spectrum

Gram positives:

MRSA
Enterococcus (non-VRE)
CoNS
Strep

Penetration

Good: skin, valves, lungs, urine, CSF (high dose)
Low–moderate: bone, biliary

ADRs

Nephrotoxicity (concentration dependent)
Ototoxicity
Infusion reaction (“Red man”)
Neutropenia
Rash

🧠 MEMORY ANCHOR:
Vanco = “Valves & Veins”
(Endocarditis + bacteremia first line)

5⃣ DAPTOMYCIN

MOA

Cyclic lipopeptide
Calcium-dependent insertion into membrane
Causes depolarization → stops DNA/RNA/protein synthesis

Bactericidal
Concentration-dependent killing

🚨 Inactivated by pulmonary surfactant
→ DO NOT use in pneumonia

Dosing (Normal Renal)

SSTI: 4–6 mg/kg IV daily
Osteomyelitis: 6–10 mg/kg IV daily
Bacteremia / IE: 8–10 mg/kg IV daily

Spectrum

Gram positives including:

MRSA
VRE
CoNS

ADRs

Myopathy
↑ CK
GI symptoms

Monitoring:
CK weekly
Consider stopping statins

🧠 MEMORY ANCHOR:
DAPTO = “Don’t use in pneumonia”

6⃣ LINEZOLID

MOA

Oxazolidinone
Binds 23S rRNA of 50S
Inhibits protein synthesis

Bacteriostatic (Staph & Enterococcus)
Bactericidal vs Strep
Time-dependent

Dosing

600 mg IV or PO q12h
No renal adjustment

Penetration

Excellent:

Lungs
CSF
Skin
Urine

ADRs

Myelosuppression (platelets!)
Peripheral neuropathy
Optic neuropathy
Lactic acidosis

DDIs

Serotonergic meds → serotonin syndrome
Adrenergic meds → ↑ BP

Food interaction:
High tyramine foods → ↑ BP

🧠 MEMORY ANCHOR:
LINEZOLID = “Platelets & Psych interactions”

7⃣ DALBAVANCIN

Long-acting lipoglycopeptide
Half-life: 14.4 days
Once weekly dosing

Used for:

SSTI
Outpatient management
Sometimes osteo/IE off-label

Renal adjustment required

🧠 Memory: DALBA = “Discharge early”

8⃣ ORAL CA-MRSA OPTIONS (Uncomplicated SSTI)

TMP-SMX

160/800 mg (DS) PO BID
Bactericidal
Limited data in bacteremia

Doxycycline

100 mg PO BID
Bacteriostatic
Low serum levels

Clindamycin

Dose varies
Bacteriostatic
High C. diff risk
Inducible resistance (D-test)

⚠ These are NOT for bacteremia or endocarditis

9⃣ 5TH GEN CEPHALOSPORINS

Ceftaroline
Ceftobiprole

Bind PBP2a
Used for:

Persistent bacteremia
Salvage therapy
High vanco MIC ≥2
Daptomycin failure

May combine with daptomycin

🔟 SITE-BASED TREATMENT PATTERN

SSTI

Preferred IV: Vancomycin
Mild oral: Doxy, TMP-SMX, Clinda
Alt: Dapto, Linezolid, Dalba

Bacteremia / Endocarditis

Preferred: Vancomycin
Alternative: Daptomycin
Off-label: Linezolid

Pneumonia

Preferred: Vancomycin
Alternative: Linezolid
🚫 NO DAPTOMYCIN

Bone & Joint

Preferred: Vancomycin
Alt: Dapto, Linezolid

🚨 HIGH-YIELD EXAM TRAPS

Daptomycin CANNOT treat pneumonia
Linezolid = no renal adjustment
Vanco requires TDM
Clindamycin → inducible resistance
TMP-SMX unreliable for bacteremia
5th gen ceph = only beta-lactams that work in MRSA
Persistent bacteremia ≥7 days → think salvage therapy

🧠 MASTER DECISION FLOW

If MRSA + bacteremia → Vancomycin
If Vanco failure or intolerance → Daptomycin
If Pneumonia → Vanco or Linezolid
If Mild SSTI → oral options
If persistent bacteremia → consider Ceftaroline ± Dapto

🟣 VRE: VANCOMYCIN RESISTANT ENTEROCOCCUS

Clean. High-yield. Pattern-based. No chaos.

1⃣ ENTEROCOCCUS BASICS (TESTABLE MICRO)

Morphology

Gram-positive cocci
Catalase negative
Coagulase negative
Seen in pairs & short chains

Normal Flora

GI tract (main)
Perineum occasionally

Two Important Species

🔵 Enterococcus faecalis (THE COMMON ONE)

80–90% of infections
Community + hospital
Ampicillin susceptible (~100%)
Vancomycin susceptible (~99%)
Daptomycin susceptible
Linezolid susceptible
Tigecycline susceptible
Ciprofloxacin ~75% (UTI only)

🧠 Memory anchor:
faeCALIS = Friendly + Community + Ampicillin works

🔴 Enterococcus faecium (THE BAD ONE)

~10%
Mostly nosocomial
Ampicillin resistant (~90%)
Vancomycin ~54% susceptible
→ If resistant = VRE
Daptomycin susceptible
Linezolid susceptible
Tigecycline susceptible

🧠 Memory anchor:
faeCIUM = ICU + Resistant

2⃣ INTRINSIC RESISTANCE (VERY TESTABLE)

Enterococcus (both species) are intrinsically resistant to:

❌ ALL cephalosporins
❌ Clindamycin
❌ TMP-SMX

🚨 This is HIGH-YIELD.

🧠 Memory anchor:
Enterococcus laughs at cephalosporins

3⃣ COMMON INFECTION SITES

UTI
Intra-abdominal
Bacteremia
Catheter-related
Endocarditis

4⃣ VRE MECHANISM (EXTREMELY TESTABLE)

VanA / VanB gene clusters

They modify:
D-Ala-D-Ala → D-Ala-D-Lactate

Result:
↓ Vancomycin binding (1000-fold reduction)

🧠 Memory anchor:
VRE = Vancomycin can’t Recognize End

5⃣ TIGECYCLINE (LAST-LINE DRUG)

Class:
Glycylcycline

MOA:
Binds 30S → inhibits protein synthesis
Bacteriostatic

Spectrum

Gram positive:

MRSA
VRE
CoNS
Strep

Gram negative:

ESBL
AmpC
Carbapenemase producers

Anaerobes
Atypicals

🚨 EXCEPTIONS:
The 3 P’s:

Pseudomonas
Proteus
Providencia

🧠 Memory anchor:
Tige covers everything except the 3 P’s

Dosing

Loading:
100–200 mg IV x1

Maintenance:
50–100 mg IV q12h

No renal adjustment
BUT hepatic adjustment (Child-Pugh C)

Penetration

Good:

Biliary
Lungs
Skin

Poor:

Urine
Serum (LOW SERUM CONCENTRATION; IT DISTRIBUTES TO THE TISSUES)

🚨 DO NOT use for:

Active bacteremia
UTIs

ADRs

Nausea (very common)
Vomiting
Pancreatitis
↑ LFTs
Photosensitivity

🚨 FDA Black Box:
↑ All-cause mortality
Use only if alternatives not suitable

🔥 HIGH-YIELD DIFFERENTIATION

faecalis → ampicillin works

faecium → often resistant

If VRE:
→ Vancomycin is useless

Use:

Linezolid
Daptomycin
Tigecycline (not bacteremia or UTI)

🚨 EXAM TRAPS

Enterococcus resistant to cephalosporins
Tigecycline NOT for bacteremia
Tigecycline NOT for UTI
VRE = D-Ala-D-Lactate
faecium more resistant than faecalis

🧠 MASTER DECISION FLOW

If Enterococcus:
→ Check species

If faecalis:
→ Ampicillin works

If faecium:
→ Often ampicillin resistant

If VRE:
→ Linezolid or Daptomycin
→ Tigecycline only salvage, not bacteremia

🟣PSEUDOMONAS AERUGINOSA

1⃣ MICRO + IDENTITY (VERY TESTABLE)

Morphology

Gram-negative bacillus
Non-lactose fermenter
Seen singly or in pairs

🧠 Memory:
Pseudo = Pale on MacConkey (non-lactose fermenter)

Habitat

Soil
Water
Moist environments
Hospital reservoirs

Thrives in:

Sinks
Ventilators
Catheters

Virulence Factors

Exotoxin A → inhibits protein synthesis
Pyocyanin → blue-green pigment
Proteases
Mucoid exopolysaccharide → biofilm

🧠 Memory:
Pseudo = Blue + Biofilm

Common Infection Sites

Pneumonia (ventilator-associated)
UTI
Bacteremia
SSTI (burns)
Ear infections (swimmer’s ear)

2⃣ RESISTANCE MECHANISMS (EXAM GOLD)

Pseudomonas is resistant because it’s built that way.

Intrinsic resistance

Porin loss
Efflux pumps
Enzymatic inactivation

Adaptive resistance

Biofilm formation

Acquired resistance

Horizontal gene transfer

🧠 Memory:
Pseudo closes doors (porins), pumps drugs out, and shares resistance genes

3⃣ ANTI-PSEUDOMONAL AGENTS (DOSE MATTERS)

🚨 These doses are HIGHER than standard.

That’s a testable trap.

🔵 PENICILLIN

Piperacillin-Tazobactam

Dose:
4.5 g IV q6h

⚠ NOT 3.375 g
That’s the usual dose — but for pseudomonas you need higher.

🧠 Memory:
Pseudo needs “Plus dosing”

🔵 CEPHALOSPORINS

Ceftazidime

2 g IV q8h

Cefepime

2 g IV q8h

🧠 Memory:
Both are 2 grams, both q8h.

🔵 CARBAPENEMS

Meropenem

500 mg IV q6h

Imipenem-Cilastatin

500 mg IV q6h

🚨 Ertapenem does NOT cover Pseudomonas

🚨 Imipenem has higher seizure risk than meropenem

🚨 Cilastatin prevents renal metabolism of imipenem

🧠 Memory:
Ertapenem = Empty for Pseudo

🔵 FLUOROQUINOLONES

Ciprofloxacin

IV:
400 mg IV q8h

PO:
750 mg PO BID

🚨 Only reliable oral option for Pseudomonas

🧠 Memory:
Cipro = Pseudo’s only oral friend

4⃣ OTHER AGENTS (Recognition Only)

You don’t need doses — just know their role.

Amikacin

Aminoglycoside
Used in severe cases

Colistin

Very toxic
Nephro + neurotoxicity
Last-line salvage

Ceftolozane-Tazobactam

Newer anti-pseudomonal agent
Used for resistant strains

Aztreonam

Monobactam
Gram-negative coverage
Can cover pseudomonas

5⃣ HIGH-YIELD EXAM TRAPS

🚨 Ertapenem does NOT cover pseudomonas
🚨 Piperacillin-tazobactam dose must be 4.5 g
🚨 Cipro is only reliable oral option
🚨 Imipenem → seizure risk
🚨 Pseudomonas = non-lactose fermenter
🚨 Biofilm formation

6⃣ MASTER PATTERN RECOGNITION

If ventilator pneumonia in ICU
→ Think Pseudomonas

If burn wound infection
→ Think Pseudomonas

If green pigment
→ Think Pseudomonas

If moist hospital reservoir
→ Think Pseudomonas

7⃣ QUICK RECALL GRID

Class	Drug	Dose
Penicillin	Pip-Tazo	4.5 g IV q6h
Ceph	Ceftazidime	2 g IV q8h
Ceph	Cefepime	2 g IV q8h
Carbapenem	Meropenem	500 mg IV q6h
Carbapenem	Imipenem	500 mg IV q6h
Fluoroquinolone	Cipro IV	400 mg q8h
Fluoroquinolone	Cipro PO	750 mg BID

🟣ENTEROBACTERALES

1⃣ WHAT ARE ENTEROBACTERALES?

Micro Basics

Gram-negative bacilli
Ferment glucose
Normal GI flora

Transmission:

Fecal-oral
Healthcare exposure
Livestock/water sources

🧠 HOW TO REMEMBER THE MAIN ENTEROBACTERALES

Think:

"KEEPC"

Klebsiella
Escherichia coli
Enterobacter
Proteus
Citrobacter

Those are the core ones.

If you know these five, you're safe on exams.

2⃣ ESBL ENTEROBACTERALES

Common ESBL organisms:

E. coli
Klebsiella pneumoniae
Klebsiella oxytoca
Proteus mirabilis

🧠 Memory:
ESBL = E. coli & Klebsiella Love Breaking cephalosporins

ESBL Mechanism

Extended-spectrum β-lactamases:

Hydrolyze most penicillins
Hydrolyze most cephalosporins
Resistant to 3rd gen cephalosporins

🚨 Cefepime may appear susceptible in vitro
BUT avoid in high-burden infections (clinical failures)

What Still Works?

✅ Carbapenems (reliably active)

MERINO Study (VERY TESTABLE)

Pip-Tazo vs Meropenem in ESBL bacteremia

30-day mortality:

Pip-Tazo = 12.3%
Meropenem = 3.7%

Absolute difference: 8.6%

🚨 Did NOT meet non-inferiority

🧠 Bottomline:
Meropenem preferred for ESBL bacteremia

3⃣ AmpC PRODUCERS

These are trickier than ESBL.

High-risk organisms:

HECLY organisms:

H — Hafnia alvei
E — Enterobacter cloacae
C — Citrobacter freundii
K — Klebsiella aerogenes
Y — Yersinia enterocolitica

🧠 Memory:
"HECL YES organisms"

AmpC Mechanism (3 Stages)

1⃣ Baseline low-level AmpC

Chromosomal
Resistant to aminopenicillins
Resistant to 1st & 2nd gen cephalosporins
May appear susceptible to 3rd gen cephs

2⃣ Inducible overproduction

Triggered by:

3rd gen cephalosporins
Pip-Tazo

Leads to:

Treatment failure during therapy

3⃣ Derepressed mutation

Permanent high-level resistance
Clinical deterioration

🚨 MOST IMPORTANT RULE FOR AmpC

Weak substrate + Weak inducer = GOOD

Cefepime
Meropenem

Strong substrate + Strong inducer = BAD

Aminopenicillins
1st gen cephs
3rd gen cephs
Pip-Tazo (risky in bacteremia)

MERINO-2 (AmpC)

Numerical trend favored meropenem.

🧠 Bottomline:
Meropenem may be preferred for AmpC bacteremia

4⃣ CRE (CARBAPENEM-RESISTANT ENTEROBACTERALES)

Definition:
Resistant to ≥1 carbapenem OR produces carbapenemase.

High mortality.
Limited options.

Common organisms:

Klebsiella pneumoniae
E. coli
Enterobacter cloacae

CRE MECHANISMS

1⃣ Carbapenemase-producing

Hydrolyze:

Penicillins
Cephalosporins
Monobactams
Carbapenems

Genes carried on plasmids → horizontal transfer

2⃣ Non-carbapenemase producing

Porin loss
Efflux pumps
AmpC overproduction

5⃣ AMBLER CLASSIFICATION (VERY TESTABLE)

Class A

Serine-based
KPC

Class B

Metallo-beta-lactamase (ZINC)
NDM

Class D

Serine-based
OXA-48

🧠 Memory:

A & D = Serine
B = Metal (zinc)

6⃣ TREATMENT PATTERNS FOR CRE

You don’t need doses — just recognition.

If KPC (Class A)

Preferred:

Meropenem-vaborbactam
Ceftazidime-avibactam
Imipenem-cilastatin-relebactam

These inhibit serine beta-lactamases.

If NDM (Class B — METAL)

Avibactam DOES NOT inhibit metallo-beta-lactamases alone.

Preferred:

Ceftazidime-avibactam + Aztreonam
Cefiderocol

If OXA-48 (Class D)

Preferred:

Ceftazidime-avibactam
Meropenem-vaborbactam
Imipenem-relebactam

If resistant to ertapenem only

But susceptible to mero/imipenem:

Use extended infusion meropenem or imipenem

7⃣ CEFIDEROCOL

Covers all CRE classes
Acts like iron → Trojan horse entry
Inhibits cell wall synthesis

🧠 Memory:
Cefiderocol = Fe (iron) delivery drug

🚨 HIGH-YIELD EXAM TRAPS

Cefepime may look susceptible in ESBL → avoid in bacteremia
Pip-Tazo inferior to meropenem in ESBL bacteremia
AmpC can induce resistance mid-therapy
HECLY organisms = AmpC
Ertapenem does NOT cover Pseudomonas
Class B = zinc-dependent
NDM requires aztreonam combo

🧠 MASTER ORGANISM MEMORY

If E. coli / Klebsiella → think ESBL
If Enterobacter / Citrobacter / Kleb aerogenes → think AmpC
If carbapenem resistance → think CRE

SID 05: Hepatitic C Virus

🧠 HEPATITIS C – ULTRA CONDENSED EXAM SHEET

1⃣ THE VIRUS

• Single-stranded RNA virus
• Replicates via NS5B RNA polymerase
• Polyprotein cleaved by NS3/4A protease

Drug Targets:

NS3/4A = protease inhibitors (glecaprevir)
NS5A = replication complex inhibitors (pibrentasvir, velpatasvir)
NS5B = RNA polymerase inhibitors
- Sofosbuvir = nucleotide inhibitor

2⃣ SCREENING & DIAGNOSIS

Step 1: HCV antibody
Step 2: HCV RNA (confirms active infection)

🚨 NEVER genotype before RNA confirmation.

3⃣ SVR = CURE

SVR12 = Undetectable RNA 12 weeks AFTER completing therapy

NOT at end of treatment.
NOT during therapy.

4⃣ THE 2 REGIMENS YOU NEED TO KNOW COLD

Everything revolves around these two.

🟢 GLECAPREVIR / PIBRENTASVIR (G/P)

• NS3/4A + NS5A
• Pangenotypic
• Safe in renal failure
• AVOID in decompensated cirrhosis

DURATIONS:

Scenario	Duration
No cirrhosis	8 weeks
Compensated cirrhosis (Child A)	12 weeks
Decompensated	❌ Do NOT use

Memory anchor:
G/P = Great & Practical → shortest option (8 weeks)

🟣 SOFOSBUVIR / VELPATASVIR (SOF/VEL)

• NS5B + NS5A
• Pangenotypic
• Avoid severe renal impairment
• Safe in decompensated cirrhosis

DURATIONS:

Scenario	Duration
No cirrhosis	12 weeks
Compensated cirrhosis	12 weeks
Decompensated	12 weeks ± ribavirin

Memory anchor:
SOF/VEL = Solid, Fixed 12 weeks

DECOMPENSATAED: SOF/VEL BY ITSELF WITH NO RIBAVIRIN = 24 WEEKS

5⃣ DECOMPENSATED CIRRHOSIS RULE

🚫 NO PROTEASE INHIBITORS

Why? Hepatotoxicity risk.

So:

❌ Glecaprevir
❌ Any “-previr”

Use:

✅ Sofosbuvir-based regimen
± Ribavirin

6⃣ RENAL FAILURE RULE

eGFR <30?

Use:

✅ G/P

Avoid:

❌ Sofosbuvir (renally cleared)

7⃣ DRUG INTERACTION TRAPS

Velpatasvir + PPIs

↓ absorption
Separate or avoid.

Take Velpatasvir 4 hours BEFORE PPI (Max omeprazole 20mg equivalent)

Sofosbuvir + Amiodarone

⚠ Severe bradycardia

8⃣ RIBAVIRIN

• Causes hemolytic anemia
• Teratogenic (contraception)
• Renally cleared
• Used mainly in decompensated cirrhosis

Memory anchor:
Riba = Ruins RBCs + Reproduction

9⃣ MONITORING

Before therapy:

HCV RNA
Fibrosis staging
Genotype (if needed)
LFTs

After therapy:

Check RNA at 12 weeks post-treatment

🔟 REINFECTION

• Yes, can be reinfected.
• Antibody stays positive forever.

🧨 THE 6 EXAM TRAPS

SVR timing
8 vs 12 weeks G/P
Using protease inhibitors in decompensated
Sofosbuvir in renal failure
Ribavirin pregnancy
PPIs with velpatasvir

FINAL 30-SECOND MEMORY GRID

🟢 G/P
No cirrhosis → 8 weeks
Cirrhosis → 12 weeks
Decomp → NO

🟣 SOF/VEL
No cirrhosis → 12 weeks
Cirrhosis → 12 weeks
Decomp → 24 weeks (12 weeks if + ribavirin)

SVR = 12 weeks AFTER

Riba = hemolysis + teratogenic

Protease inhibitors = NO in decomp

Renal failure → choose G/P

🧠 HIV THERAPEUTICS — ULTRA MORNING RECALL SHEET

🦠 1. Core Treatment Principle

✔ Treat ALL patients immediately
✔ Goal = Viral suppression (<50 copies/mL)
✔ U = U (Undetectable = Untransmittable)

💊 2. FIRST-LINE REGIMENS (MOST IMPORTANT)

⭐ Preferred Backbone

2 NRTIs + INSTI

Most common:

Dolutegravir + TAF/FTC
Bictegravir/TAF/FTC (single tablet)

INSTIs = FIRST LINE.

Memory anchor:

“DTG and BIC run the show.”

🧬 3. Drug Classes + Mechanisms

NRTIs

Fake nucleotides → chain termination
Examples:

TDF
TAF
Abacavir
Lamivudine
Emtricitabine

NNRTIs

Bind reverse transcriptase directly
Example:

Efavirenz (CNS dreams 😵‍💫)

INSTIs

Block integration of viral DNA
Examples:

Dolutegravir
Bictegravir
Raltegravir

⭐ Best tolerated
⭐ First-line
⭐ Few DDIs
⚠ Separate from iron/calcium/magnesium

Protease Inhibitors (PIs)

Block viral maturation
Example:

Darunavir (needs boosting)

High resistance barrier
High metabolic side effects

🚨 4. HIGH-YIELD DRUG TRAPS

🔴 Abacavir

Check HLA-B*5701
↑ cardiovascular risk

🔴 TDF

Renal toxicity
↓ Bone mineral density

🔵 TAF

Safer kidneys & bones
Preferred over TDF

🔴 Dolutegravir

Mild ↑ creatinine (NOT renal damage)
Cation interaction (iron, Ca, Mg)

Memory:

“DTG lies about creatinine.”

🔴 Efavirenz

CNS effects
Vivid dreams
Psychiatric issues

🔴 Boosted PIs

Need ritonavir or cobicistat
CYP3A4 inhibition
Metabolic syndrome risk

🧪 5. Monitoring

✔ Viral load
✔ CD4
✔ Renal function (TDF)
✔ HLA-B*5701 (before abacavir)

🔥 6. Resistance Barrier Ranking

Highest → Boosted PIs
High → Dolutegravir/Bictegravir
Low → NNRTIs

Exam trick:
NNRTIs fail fast.

🧬 7. HIV + Hepatitis B

Tenofovir treats BOTH HIV + HBV.

⚠ Stopping tenofovir in co-infected patient → HBV flare.

🧪 8. Maraviroc

CCR5 blocker
Must check tropism test first

Memory:

“No CCR5 test, no maraviroc.”

💉 9. PEP (Post-Exposure Prophylaxis)

Duration = 28 days

Preferred:
TDF/FTC + Dolutegravir

🤰 10. Pregnancy

Dolutegravir = safe
Efavirenz = now considered safe

(Older exams used to avoid DTG early pregnancy — that’s outdated.)

🎯 11. Absolute Must-Remember Exam Traps

✔ INSTIs = first line
✔ TDF = kidney + bone
✔ Abacavir = HLA-B*5701 + CV risk
✔ Dolutegravir = fake creatinine rise
✔ Boosted PIs = CYP interactions
✔ 28 days PEP
✔ U = U

🧘🏻‍♀️ Final Mental Check

If the question asks:

Best initial therapy → INSTI-based
Kidney issues → Avoid TDF
CV disease → Avoid Abacavir
High DDI concern → Avoid boosted PIs
HBV coinfection → MUST include tenofovir