Pneumonia

2005 HAP/VAP/HCAP Guidelines

1. Is it a late onset (patient is in hospital for >5 days)?

   or

2. Does the patient have a risk factor multiple drug resistance?

No- Use limited spectrum antibiotic therapy (less aggressive antibiotics)

Yes- Use broad spectrum antibiotic therapy (more aggressive)

Risk Factors for Multiple Drug Resistance

• Antibiotics used in the last 90 days

• >5 days hospitalized

• High frequency of antibiotic resistance in the community or hospital

• Any of the following HCAP risk factors:

  • Stayed in a hospital for 2 or more days in the last 90 days

  • Lives in a nursing home or long-term care facility

  • Gets home IV antibiotics

  • On chronic dialysis within the last 30 days

  • Receives home wound care

  • Lives with someone who has drug-resistant infections

  • Has a weakened immune system

What happened after the 2005 HCAP guidelines came out?

• Studies looked into the guidelines and found problems:

  • No clear improvement in patient outcomes

  • The criteria didn’t do a good job identifying patients with drug-resistant bacteria

• Resulted in 15 years of antibiotic overprescribing

• Doctors still sometimes use the old HCAP definition to justify giving strong antibiotics, even though it’s no longer recommended

Pathophysiology of pneumonia

1. Microbe invades the airway

   • Bacteria gets into the lungs through:

   • Inhalation

   • Aspiration (accidentally breathing in food, saliva, or vomit)

   • Bloodstream spread from another infected part of the body

2. Body’s defence are overcome

   • Normally, your lungs have defense systems like:

     • Mucociliary clearance – tiny hairs and mucus that trap and remove germs

     • Macrophages – immune cells that “eat” invaders

   • But in pneumonia:

     • These defenses are damaged or not working well

     • Bacteria slip through and start growing

3. Bacteria grow and cause inflammation

   • Bacteria reach the alveoli (tiny air sacs in the lungs)

   • The immune system reacts:

     • Macrophages call in neutrophils (another type of immune cell)

     • These cells release cytokines (chemical signals) to fight infection, but this also causes inflammation

Signs / Symptoms of pneumonia

• New or worsening sputum (saliva) production

• New or worsening cough

• Increased respiratory rate

• Pleuritic chest pain

  • Sharp chest pain that gets worse when you take a deep breath or cough

• Leukocytosis / Leukopenia

• Fever / Hypothermia

• Auscultatory changes

  • Like crackles or rales when doctor listens to your chest

• Decrease in oxygenation

Diagnosis of Pneumonia

• Chest X-ray is the main tool to use

• What do doctors look for in the x-ray:

• Infiltrate or consolidation

  • These are cloudy areas that suggest infection or fluid in the lungs

  • May indicate pneumonia, but…

  • The X-ray can’t tell if the pneumonia is caused by bacteria or viruses

• What if the X-ray looks normal, but the patient has symptoms?

  • Wait 24–48 hours and then repeat the X-ray

  • Sometimes early pneumonia doesn’t show up right away on the image

Sputum Analysis

• It’s when doctors test the mucus (sputum) you cough up to see which bacteria might be causing your pneumonia

• But there’s a challenge…

  • 40–60% of people with pneumonia can’t produce sputum at all

  • Of the ones who can, many samples are poor quality and not helpful

• When should cultures definitely be done?

  • If the pneumonia is severe (e.g., ICU patients)

  • If the patient is being treated for MRSA or Pseudomonas aeruginosa

    • These are serious drug-resistant bacteria, so it’s important to know for sure

What makes a “good” sputum sample?

• Lots of PMNs (immune cells which help fight infection)

• Few epithelial cells from the mouth

• Specifically:

  • More than 25 PMNs

  • Less than 10 epithelial cells

• This tells us the sample likely came from the lungs, not just spit

Procalcitonin

• A substance normally made in the thyroid (by C-cells)

• In healthy people, it's turned into calcitonin (a hormone that helps regulate calcium)

• What happens during a bacterial infection?

  • Other parts of the body, like fat cells (adipocytes), start making lots of procalcitonin (PCT) in response to bacterial signals (like LPS, IL-1β, TNF-α)

  • These cells can’t convert PCT to calcitonin, so PCT builds up in the blood

  • High PCT = likely bacterial infection

• What about viral infections?

  • Interferon-γ (IFN-γ), which is high during viral infections, blocks PCT production

  • So PCT levels usually stay low in viral infections

• Why is this useful?

  • Doctors can measure PCT levels in the blood to help decide:

    • Is the infection bacterial (high PCT)?

    • Or viral (low PCT)?

  • It’s especially studied in:

    • CAP (community-acquired pneumonia)

    • Sepsis

• PCT levels usually peak within 24 hours after a bacterial infection starts

• Sometimes it rises a little with viral infections too, but then it quickly drops

The most common PCT level used to suggest bacterial pneumonia is…..

> 0.25 ng/mL

Pneumonia Testing Algorithm

1. A patient comes in with signs of an LRTI (like cough, fever, shortness of breath)

2. Do a clinical assessment (look at symptoms, vitals, exam, etc.)

3. Perform a PCT test

a. If PCT: < 0.1 ng/mL

• Very low likelihood of bacterial infection

• Antibiotic therapy strongly discouraged

b. PCT: 0.1 - 0.25 ng/mL

• Low likelihood of bacterial infection

• Antibiotic therapy discouraged

c. PCT: 0.25-0.5 ng/mL

• Higher chance of bacterial infection

• Antibiotic therapy encouraged

d. PCT: >0.5 ng/mL

• Strong evidence of bacterial infection

• Antibiotic therapy strongly encouraged

Things to Consider with PCT

• If the patient is unstable, high-risk, or has severe symptoms, antibiotics might still be started, even if the PCT is low

• Re-evaluation is recommended regularly to avoid unnecessary prolonged antibiotic use

• Repeat Testing:

  • Low-risk: Repeat PCT in 1–2 days

  • Moderate-risk: Repeat in 6–12 hours

  • High-risk / On antibiotics: Recheck every 2–3 days, and stop antibiotics early if PCT drops

2019 Guideline Recommendations for PCT

• Do not use PCT to decide whether to start antibiotics if:

  • The patient already has pneumonia confirmed on a chest X-ray

  • And has symptoms (like cough, fever, or low oxygen)

• So, even if the PCT is low, if the X-ray and clinical signs point to pneumonia → still treat

• Very low (i.e. ≤ 0.1 µg/mL) levels typically indicate lack of bacterial infection

• Higher PCT levels may mean bacterial infection, but:

  • There’s no official cutoff that clearly separates viral from bacterial

• In cases where the infection is both viral and bacterial, the PCT might still be low, making it less reliable

• Using PCT to track progress (serial testing) doesn’t seem to help much in shortening how long patients are on antibiotics

Pneumonia Severity Index Scoring

• 

CURB-65

1 point each:

• C – Confusion

• U – Uremia (BUN > 20 mg/dL)

• R – Respiratory rate > 30 bpm

• B – Blood pressure < 90/ 60

• Age 65 – Age ≥ 65 years

Score	Treatment Setting
0-1	Outpatient
2	Inpatient- floor
≥ 3	Inpatient- ICU

Why do guideline recommend PSI over CURB65?

• Identifying low-risk patients → more patients can safely be treated at home

• Predicting mortality → more accurate in telling who is truly at risk

• Validated in studies → proven useful in multiple clinical trials

• But always combine with clinical judgment — because scores don't know everything

• Examples:

  • A patient may still need admission if:

  • They have medical issues (e.g., unstable heart disease)

  • They have psychosocial issues (e.g., live alone, can’t care for themselves)

  • PSI might underestimate risk in younger patients since younger age lowers the score, even if they’re really sick

  • You must also think about their baseline health (e.g., a chronically ill patient might appear “low risk” on paper)

Determining ICU Admission for Pneumonia

• IDSA (Infectious Diseases Society of America) severity criteria helps to decide

• It works alongside clinical judgment, it doesn’t replace it!

• ICU admission is recommended if:

  • The patient meets 1 major criterion
    OR

  • Meets 3 or more minor criteria

• Other tools like SMART-COP exist, but:

  • They may need extra lab work

  • They don’t seem to work better than IDSA’s criteria

  • IDSA is more practical and validated

IDSA Major Criteria

Need only 1

IDSA Minor Criteria

Needs 3 or more to be allowed in the ICU

Most common Bacterias that Cause pneumonia

• Strep pneumonia

• Haemophilus influenzae

• Mycoplasma pneumoniae

• Clamydophilia pneumoniae

• Legionella pneumophilia

• S. aureus (rare, risk factors for infection)

Community-Acquired Pneumonia (CAP)

• Most of the time… we don’t know the exact cause!

• In up to 62% of cases, no pathogen is identified, even after testing

• 24% are viral pathogens

• 14% are bacterial pathogens

• About 3% of cases have both bacteria and virus at the same time

Risk Factors for MRSA and Pseudomonas aeruginosa in CAP

• It’s rare for CAP to be caused by MRSA or Pseudomonas

• These are resistant and serious bacteria, but not common in most community cases

• Most consistent risk factors:

  1. Previous infection with MRSA or Pseudomonas

     • Especially if it was a lung infection (like pneumonia or bronchitis)

  2. Recent hospitalization WITH IV antibiotics

     • If the patient was in the hospital and received IV antibiotics within the past 90 days

MRSA in the community

• Some MRSA strains produce a toxin called Panton-Valentine Leukocidin (PVL)

• This toxin kills white blood cells and damages lung tissue

• The result is cavitary pneumonia , areas of the lung break down and form holes or cavities

• Still very uncommon overall

• All Staphylococcus aureus infections make up only ~1% of all community-acquired pneumonia (CAP)

First Line: Outpatient, otherwise healthy

• Amoxicillin

  OR

• Doxycycline

Alternative Line: Outpatient, otherwise healthy

if local resistance to S. pneumoniae is <25%

• Azithromycin

  OR

• Clarithromycin

Outpatient WITH comorbidities examples

• chronic heart/lung/liver/renal disease

• diabetes

• asplenia

• malignancy

• alcoholism

First Line: Outpatient WITH comorbidities

• Amoxicillin/clavulanate

  OR

• Cefpodoxime

  OR

• Cefuroxime

  PLUS

• Azithromycin OR doxycycline

Alternative Line: Outpatient WITH comorbidities

• Levofloxacin

  OR

• Moxifloxacin

First Line: Inpatient, non-ICU, no MRSA/P. aeruginosa risk factors

• IV β-lactam PLUS azithromycin

IV Beta-Lactams

• Ceftriaxone

• Ceftaroline

• Cefotaxime

• Ampicillin-sulbactam

Alternative Line: Inpatient, non-ICU, no MRSA/P. aeruginosa risk factors

• Levofloxacin

  OR

• Moxifloxacin
  OR

• IV β-lactam + doxycycline

First Line: Inpatient, non-ICU, recent IV antibiotics

• IV β-lactam PLUS azithromycin

First Line: Inpatient, non-ICU, Recent MRSA infection

• IV β-lactam PLUS azithromycin + MRSA coverage

First Line: Inpatient, non-ICU: Recent P. aeruginosa infection

• Antipseudomonal IV β-lactam

First Line: Inpatient, ICU: no MRSA/P. aeruginosa risk factors

• IV β-lactam PLUS azithromycin

Alternative Line: Inpatient, ICU: no MRSA/P. aeruginosa risk factors

• IV β-lactam

  PLUS

• Levofloxacin

  OR

• Moxifloxacin

First Line: Inpatient, ICU: with risk factors

• Vancomycin

  OR

• Linezolid

  PLUS

• Antipseudomonal β-lactam

What if cultures come back negative with MRSA/Pseudomonas?

• If cultures are negative at 48 hours, you can stop MRSA or Pseudomonas drugs safely

• If the MRSA nasal PCR is negative, you can stop vancomycin or linezolid

• For MRSA - you can stop if either of those are happening

MRSA Nasal PCR

• Quick nose swab test that checks if MRSA is living in your nose (colonization)

• This doesn’t mean you’re sick, just that MRSA is hanging out there

• If the nasal PCR is negative, it means the patient probably does not have MRSA pneumonia.

• So: You can safely stop MRSA drugs

• A positive just means the person has MRSA in their nose,
  but doesn’t confirm they have MRSA in the lungs

• So: You can’t make decisions based on a positive alone, you still need to look at cultures and symptoms

Pneumococcal Urinary Antigen Test (additional pneumonia test)

• Not recommended for most people

• Use it only in severe cases, like ICU patients with very sick CAP

• It looks for a piece of the Streptococcus pneumoniae cell wall in the urine

• It helps check if S. pneumoniae (the most common CAP bug) might be the cause of pneumonia

• High specificity (>94%)

  • If the test is positive, it’s probably real

• Varied sensitivity (>65%)

  • If the test is negative, it might still miss some true cases

• It works best when the patient has bacteremia (bacteria in the blood), that boosts the test's reliability

• Even if the test is positive, doctors usually still give the same antibiotics, so it doesn’t change the treatment plan much

• That’s why it’s not recommended routinely, except maybe in severe cases (ICU)

Legionella Urinary Antigen Test (additional pneumonia test)

• Not recommended for most people, except for:

  • Severe pneumonia (like in ICU)

    Epidemiologic clues, like:

    • Local outbreak

    • Travel to hotel, cruise, etc. (think contaminated water systems)

• Is a urine test that looks for antigens (proteins) from Legionella pneumophila, the bacteria that causes Legionnaires’ disease, a type of severe pneumonia

• Detects only serotype 1

  • Serotype 1 is the most common cause of Legionella pneumonia (~84% of cases)

  • So this test misses other serotypes, that’s a limitation

• 99% specificity (damnnn)

• The test may stay positive for weeks to months, even after the patient is cured

• So it's not useful to monitor response to treatment, just good for diagnosis

Legionella Pneumophila

• A bacteria that causes a serious type of pneumonia called Legionnaires’ disease

• Becoming more common in recent years

• Usually comes from environmental water sources:

  • Like hot tubs, cooling towers, or air conditioning systems

• Symptoms:

  • Muscle aches

  • Dry cough (non-productive)

  • High fever

  • Gets worse fast

• Chest x-ray shows patchy infiltrates or nodular infiltrates (uneven or spotty infection, not a classic pattern)

• These patients are often very sick and may need hospitalization, even ICU care

Aspiration Pneumonia/Pneumonitis

• Aspiration is something other than air (like food, saliva, vomit) accidentally goes into the lungs

• Most often seen in:

  • Elderly patients

  • People from nursing homes or long-term care

• Hard to tell the difference:

  • Pneumonia = infection

  • Pneumonitis = inflammation without infection

• You don't need to add more antibiotics (like anaerobic medication (anaerobes already in mouth)) just because a patient aspirated

• Stick with the normal pneumonia meds, unless there’s a clear reason to go bigger

Pneumonia

Infection

Pneumonitis

Inflammation without infection

Treatment Duration for CAP

• 5–7 days

• You can stop antibiotics earlier if:

  • The patient is afebrile (no fever) for 48–72 hours

  • Their symptoms are improving

• CAP Newly Approved Medication: fluoroquinolones, macrolides (these should not exceed 5 days)

• Some patients with mild CAP might do well with just 3 days of antibiotics if they respond quickly

• Guidelines say: Max 7 days, unless the patient isn’t improving

Shorter Treatment of CAP

• A randomized controlled trial (RCT) studied 3 days vs 8 days of treatment.

• Population studied:

  • Non-critically ill

  • Immunocompetent

  • Clinically stable after 3 days of β-lactam antibiotics

• Result: No significant difference in outcomes (just waste of money to stay in hospital for that long)

Shorter Treatment of CAP Exclusions

• Aspiration pneumonia

• Legionella

• Atypical pathogens

• Lung abscess

• Large pleural effusion

Directed Therapy vs Empiric Therapy

• Empiric Therapy

  • You don’t know the exact bug yet, so you treat with broad coverage just in case

• Directed Therapy

  • Once a specific bug is found (from cultures or tests), you narrow the treatment based on that bug’s susceptibility (what drugs it’s sensitive to) (so you know the bacteria already)

• Most of the time, no pathogen is identified, so you just stick with empiric therapy

• If you do find the bug → use directed therapy based on that organism’s resistance/sensitivity pattern

Directed Therapy for Legionella spp

• Levofloxacin

  OR

• Azithromycin

Lefamulin Class

Pleuromutilin (new)

Lefamulin

• Approved drug for CAP

• Also Used for: S. aureus

• Side Effects:

  • QT prolongation

  • Diarrhea

• Cost:

  • Oral: ~$275/day

  • IV: ~$205/day

• Dose Adjustment:

  • Decrease dose with reduced hepatic function

Omadacycline Class

Tetracycline

Omadacycline

• Approved drug for CAP

• Also Used for:

  • S. aureus

  • E. faecalis

  • Enterobacteriaceae

• Other Indication:

  • SSTI

• Side Effects:

  • Nausea/ vomiting

  • Increased LFTs

• Cost:

  • Oral: ~$237/day

  • IV: ~$414/day

• Dose Adjustment:

  • No dose adjustments

Delafloxacin Class

Fluoroquinolone

Delafloxacin

• Approved drug for CAP

• Also Used for:

  • S. aureus

  • P. aeruginosa

  • Enterobacteriaceae

• Other Indication:

  • SSTI

• Side Effects:

  • Nausea/ vomiting

  • FQ black box warning

• Cost:

  • Oral: ~$180/day

  • IV:~$319/day

• Dose Adjustment:

  • Decrease dose with reduced renal function (IV only)

Role for New Drugs for CAP

• Not in severe CAP

  • These drugs were tested mostly in milder pneumonia cases, where patients didn’t need to be admitted to the hospital or ICU

• Most helpful in PORT Class IV or lower (moderate risk)

• Non-β-lactams

  • Great option if a patient is allergic to β-lactams

  • Effective against common pneumonia-causing bacteria

  • But they are much more expensive than the usual antibiotics

Bacterial CAP most commonly caused by…

S. pneumoniae

HAP

• Pneumonia that develops ≥48 hours after hospital admission (not present at admission)

• Intubation as a result of developing HAP is NOT a VAP

• Pneumonia developing < 48 hours after admission is CAP

VAP

• Pneumonia that develops ≥48 hours after intubation

HAP / VAP

• Most common hospital-acquired infection:

  • Makes up 22% of all hospital-acquired infections

  • 10% of ventilated patients get VAP

• Serious impact:

  • Associated with high morbidity and mortality

  • Patients stay longer on the ventilator, longer in the hospital, and it costs more

Pathophysiology of VAP

• Colonization of the upper respiratory tract

  • Bacteria build up in the mouth, throat, or trachea (often from the hospital environment)

• Host defenses are bypassed

  • Normally, your upper airway (like the nose and throat) filters out bacteria

  • But when a ventilator (endotracheal tube) is inserted, that defense is skipped

  • Mucociliary clearance is also impaired

• Bacteria pass through or around the endotracheal tube

  • Microorganisms can:

    • Travel down inside the tube

    • Or leak around the cuff that’s meant to seal the airway

HAP/VAP Diagnosis

• Chest X-ray

• But X-ray alone isn’t specific — it helps support the diagnosis, not confirm it alone

• Quantitative Sampling

  • Samples from the lower respiratory tract are tested for bacterial load

  • There are cutoffs) to decide if the growth is significant or just colonization (like serious or just normal)

Signs and Symptoms of HAP/VAP

• New or worsening sputum (mucus) production

• New or worsening cough

• Increased respiratory rate (breathing faster)

• Pleuritic chest pain (pain when breathing in)

• Decreased oxygenation (patient needs more oxygen or has lower oxygen levels)

• Fever or hypothermia (low temp)

• Leukocytosis or leukopenia

• Lung Sounds (auscultation)

  • Crackles or rales

• Changes in Ventilator Settings

  • Increasing FiO₂

  • Increased RR

  • Worsening respiratory acidosis (more CO2 in blood)

Non-Invasive Sampling Type (HAP/VAP)

• Sputum

  • Patient coughs up mucus for testing

• Tracheal aspirate

  • Diagnostic threshold: >10⁵ CFU/mL

  • Means infection is likely if bacteria grow at this level

Invasive Sampling (HAP/VAP)

• Bronchoalveolar Lavage (BAL)

  • Diagnostic threshold: >10⁴ CFU/mL

• miniBAL / non-bronchoscopic BAL

  • Diagnostic threshold: >10⁴ CFU/mL

• Protected specimen brush

  • Diagnostic threshold: >10³ CFU/mL

Bronchoalveolar Lavage (BAL)

• Quantitative culture method used to:

  • Collect fluid from deep inside the lungs

  • Measure bacteria levels to help diagnose pneumonia

• A bronchoscope (thin tube with a camera) is inserted through the nose or mouth

• Sterile fluid is squirted into a small part of the lung

• The fluid is suctioned back and sent to the lab for culture

• Looks for the amount and type of bacteria present.

• Threshold for infection is usually >10⁴ CFU/mL

mini-BAL (non-bronchoscopic BAL)

• A blind version of BAL (no camera used)

• Still collects fluid, but less precise because it doesn’t visualize the lungs

Sampling Recommandation for HAP/VAP

• Routine invasive sampling is no longer recommended for VAP

• Guidelines now say don’t do invasive sampling automatically

• Why?

  • Studies show no major difference in outcomes between invasive (e.g., BAL) and non-invasive (e.g., sputum, tracheal aspirate) methods

  • More strong studies are still needed

• If you do use invasive sampling (like BAL):

  • Only treat with antibiotics if the bacterial count is above the diagnostic threshold (e.g., >10⁴ CFU/mL for BAL)

  • If below threshold = don’t treat, because it's likely colonization, not infection

• Non-invasive sampling is fine and useful

  • Results from sputum or tracheal aspirates should be used to guide antibiotic choices

Biomarkers for HAP/VAP

• Procalcitonin (sounds familiar…)

  • A precursor to calcitonin, but it rises specifically in response to bacterial infections (especially due to endotoxins)

  • Why it matters:

    • Helps differentiate bacterial from viral pneumonia

    • Can be used to guide when to stop antibiotics if levels drop

    • Has been studied the most out of the three listed

Use Procalcitonin for Starting Antibiotics for HAP/VAP?

• No — avoid using it to start antibiotics

• Should not replace clinical judgment (symptoms, CXR, vitals, etc.)

• Studies used different cutoffs, making it unreliable for deciding when to start treatment

Use Procalcitonin for Stopping Antibiotics in HAP/VAP?

• Yes, it may help guide when to stop antibiotics

• Good for helping prevent overuse of antibiotics

  • VAP studies show that using procalcitonin to guide stopping therapy:

    • Reduced treatment duration (from 12.1 to 9.1 days)

    • No increase in failure or mortality

Nosocomial Pneumonia Bacteria

• Staphylococcus aureus

• Pseudomonas aeruginosa

• Klebsiella pneumoniae

• E. coli

• Enterobacter spp.

• Acinetobacter baumannii

Empiric Antibiotic Therapy for HAP/VAP

• Guided by Local Susceptibilities

  • Use your hospital’s antibiogram (especially VAP-specific if available)

  • This shows how common bacteria respond to antibiotics in your setting

• Coverage Should Include:

  • Staphylococcus aureus

  • Pseudomonas aeruginosa

  • Other Gram-negatives

When to add MRSA coverage to empiric therapy in HAP/VAP patient

• IV antibiotics in the past 90 days

• High risk of mortality (e.g., septic shock, or on the ventilator for HAP)

• Unit MRSA rate > 20%

Empiric MRSA for VAP

• Hospitalized for ≥5 days

• Had ARDS before VAP

• On dialysis/renal replacement therapy before VAP started

MRSA Pneumonia Agents

1. Vancomycin

   • 15 mg/kg IV every 8–12 hours

   • Add a loading dose (25–30 mg/kg once) for severely ill patients

2. Linezolid

   • 600 mg IV every 12 hours

Vancomycin vs. Linezoild

• Prospective, double-blind, multicenter

• 448 patients

• Compared:

  • Linezolid 600 mg IV q12h

  • Vancomycin 15 mg/kg IV q12h, goal trough 15–20 µg/mL

• Mortality: No significant difference (15.7% for linezolid vs 17% for vancomycin).

• Clinical cure: Higher in the linezolid group (57.6% vs 46.6%) — this was statistically significant

• Kidney safety: Linezolid caused less kidney damage (nephrotoxicity) than vancomycin (8.4% vs 18.2%)

Empiric Gram-Negative Coverage

• Goal:

  • Ensure activity against Pseudomonas, a tough gram-negative bug often found in hospital infections

• Adjust coverage if the patient has risk factors like:

  • Septic shock or ventilator support (high mortality risk)

  • Received IV antibiotics in the last 90 days

  • VAP-specific risks, such as:

    • Local resistance >10%

    • ARDS (acute respiratory distress syndrome)

    • On dialysis or other renal replacement therapy

    • Hospitalized ≥ 5 days

Antibiotic Options for Pseudomas (Antipseudomonals!!)

• Pip-Tazo (anti-pseudomal pen)

• Cefepime or Ceftazidime – both are cephalosporins, but:

  • Cefepime covers MSSA

  • Ceftazidime does NOT cover MSSA

• Imipenem or Meropenem

• Aztreonam (does NOT cover MSSA)

Who needs combo therapy?

• Patients with:

  • High risk of mortality (e.g., septic shock)

  • Risk factors for MDR organisms (like previous antibiotic use, prolonged hospitalization)

Combination therapy for gram-negative infections

• Ciprofloxacin or Levofloxacin

• Amikacin or Gentamicin or Tobramycin

• Colistin or Polymyxin B

• So you combine these, with:

• Pip-Tazo (anti-pseudomal pen)

• Cefepime or Ceftazidime – both are cephalosporins, but:

  • Cefepime covers MSSA

  • Ceftazidime does NOT cover MSSA

• Imipenem or Meropenem

• Aztreonam (does NOT cover MSSA)

Empiric Treatment: HAP

1. Did the patient develop pneumonia ≥ 48 hours after hospital admission?

   • If yes → move to next step. (This makes it HAP, not CAP.)

2. Does the patient have any of these high-risk factors?

   • Septic shock

   • Ventilator support

   • Received IV antibiotics in the last 90 days

   • If YES → Give MRSA coverage + Double Gram-negative coverage

   • If NO → go to step 3

3. Is the local MRSA rate > 20%?

   • If YES → Give MRSA coverage + Antipseudomonal β-lactam

   • If NO → Just give an antipseudomonal β-lactam

   • But make sure it also covers MSSA, not just Pseudomonas

Empiric Treatment: VAP

1. Did the patient develop pneumonia ≥ 48 hours after incubation admission?

   • If yes → This is VAP

2. Are there any of the following high-risk factors?

   • Septic shock

   • IV antibiotics used within the past 90 days

   • Hospitalized ≥ 5 days before VAP onset

   • Acute respiratory distress syndrome (ARDS)

   • Acute renal replacement therapy (ARRT)

   • If YES → Go to Step 3

   • If NO → Go to Step 3B

3. Step 3A: (High-Risk Patients)

   • MRSA Coverage + double antipseudomonal coverage

4. Step 3B: (Lower-Risk Patients)

   • You can consider just 1 Gram-negative drug and skip MRSA coverage only if:

     • Pseudomonas resistance to single agents is <10%

     • MRSA prevalence is <10–20%

     • If your hospital antibiogram shows low resistance, use:

     • A single β-lactam that covers MSSA and Pseudomonas
       (like pip/tazo, cefepime, meropenem)

How long should you give antibiotics for VAP?

• 7 days

• BUT...

• If the VAP is caused by non-fermenting gram-negative bacilli (NF-GNB) like:

  • Pseudomonas aeruginosa

  • Acinetobacter baumannii

  • Stenotrophomonas maltophilia

  These are harder to kill and more likely to come back — so 7 days might not be enough

• But if they are improving stick the 7 days

Inhaled Antibiotics in VAP

• Use adjunctive inhaled antibiotics (in addition to IV)

• Only if the bacteria causing the infection are:

  • Only treatable by aminoglycosides (like gentamicin or amikacin)
    OR

  • Only treatable by polymyxins (like colistin or polymyxin B)

  • So: If regular IV antibiotics won’t work and the only antibiotics that work are the ones you can also give through inhalation, then you can add inhaled versions to boost treatment.

• But is inhaled therapy good enough on its own

  • Don’t use inhaled antibiotics alone — always pair them with IV antibiotics.

• Meta-analysis (a big study that combines lots of studies) found:

  • More people had their infection go away (higher cure rate)

  • It did NOT lower the death rate

  • It did NOT increase kidney problems

  • So, it helps the infection clear up faster but doesn’t change whether someone survives or not