Hospital-Acquired Pneumonia (HAP) treatment, What is the most common cause of HAP?

by Heba Soffar · November 25, 2024

Hospital-acquired pneumonia (HAP) (Nosocomial Pneumonia) is a type of pneumonia that develops 48 hours or more after hospital admission and is not present or incubating at the time of admission, It is a serious healthcare-associated infection with significant morbidity, mortality, and healthcare costs.

Hospital-Acquired Pneumonia (HAP)

HAP: is pneumonia that occurs 48 hours or more after admission and does not appear to be incubating at the time of admission.

Ventilator-associated pneumonia (VAP:) is a subtype of HAP that develops more than 48-72 hours after endotracheal intubation.

Healthcare-associated pneumonia (HCAP): Any patient who:

Hospitalized in an acute care hospital for two or more days within the last 90 days.
Resided in a nursing home or long-term care facility.
Received recent IV antibiotics, chemotherapy, or wound care within the past 30 days.

Hospital-Acquired Pneumonia

Incidence

13-1.8% of Nosocomial infection.
10-25% of ICU patients.
Mortality up to 70%.

Nosocomial Pneumonia

Pathogens

G-ve bacilli (60%): Pseudomonas aeruginosa, Klebsiella, Proteus, E. coli, Hemophilus influenzae, Moraxella catarrhalis.
G+ve cocci (20-40%): Staphylococcus aureus, Streptococcus pneumoniae.
Anaerobic bacteria, Mycobacterium tuberculosis, viruses, fungi or protozoa.

Pathogenesis

Bacterial colonization of the aerodigestive tract by gram-negative enteric bacteria (core organism) and aspiration of the contaminated secretions into the normally sterile lower respiratory tract within the first 5 days (early onset).
Cross-transmission between patients through healthcare personnel (late-onset i.e., after 5 days).

Diagnosis of nosocomial pneumonia

Alveolar infiltrates on chest X-ray + 2 or more of the following: Hypo/hyperthermia (<36 or > 38 °C). Leucopenia or leukocytosis. Purulent tracheal secretions. Decreased PaO2.
Qualitative and quantitative culture of lower airway secretions.
blood culture which is mandatory (Low sensitivity + specificity).
Quantitative culture using invasive methods (PSB+BAL): PSB: Protected specimen brush, BAL: Broncho-Alveolar lavage.

Diagnosis of ventilator-associated pneumonia (VAP)

New and persistent X-ray infiltrates + one of the following:

Positive culture of pleura, blood, or tracheal aspirates.
X-ray cavitations.
Histopathologic evidence.
New fever and leukocytosis.

Risk Factors

Recent abdominal surgery.
Witnessed aspiration.
D.M.
Prolonged ICU stay.
Coma.
Corticosteroids.
Head trauma.
Prior antibiotics.
Renal failure.
Structure lung disease.

Onset

Early before 5 days.
Late on or after 5 days.

Sever Pneumonia = ICU

Respiratory rate > 35/min.
Hypoxemia.
There is a need for M. V.
Rapid X-ray worsening.
Shock.
Oligure.
Renal failure.

Risk Factors for Multidrug-Resistant Pathogens

Risk factors for MDR VAP

Prior intravenous antibiotic use within 90 d.
Septic shock at the time of VAP.
ARDS preceding VAP.
Five or more days of hospitalization before the occurrence of VAP.
Acute renal replacement therapy prior to VAP onset.

Risk factors for MDR HAP

Prior intravenous antibiotic use within 90 d.

Risk factors for MRSA VAP/HAP

Prior intravenous antibiotic use within 90 d.

Risk factors for MDR Pseudomonas VAP/HAP

Prior intravenous antibiotic use within 90 d.

Treatment

Recommended Initial Empiric Antibiotic Therapy for Hospital-Acquired Pneumonia (HAP) (Non- Ventilator-Associated Pneumonia)

1. Category I: (Monotherapy)

Not at high risk of mortality or drug resistance→ Choose one antibiotic from the following groups:

Antipseudomonal cephalosporin e.g., Cefepime or Ceftazidime.
Carbapenems e.g., Imipenem or Meropenem.
Antipseudomonal fluoroquinolone e.g., Levofloxacin or Ciprofloxacin.

If associated factors Increase the likelihood of MRSA → add anti-MRSA e.g. Linezolid or Vancomycin, Teicoplanin (Most common used in Egypt).

2. Category II: (Triple therapy)

High risk of mortality or receipt of intravenous antibiotics during the prior 90 days: Give Double antipseudomonal + anti-MRSA (Linezolid or Vancomycin).

The first antipseudomonal should be an antipseudomonal cephalosporin (Cefepime or Ceftazidime) or an antipseudomonal penicillin (Piperacillin- tazobactam) or a carbapenem (imipenem or Meropenem).
The second antipseudomonal should be an antipseudomonal fluoroquinolone (Levofloxacin or Ciprofloxacin) or an aminoglycoside (Amikacin or Gentamycin).
Empirical anti-MRSA: (Linezolid or Vancomycin).

Recommended Initial Empiric Antibiotic Therapy for Ventilator-Associated Pneumonia (VAP)

Same treatment as category II in HAP (Double antipseudomonal + Anti MRSA)

Antipseudomonal cephalosporin eg. Cefepime or ceftazidime.
Or Antipseudomonal penicillins eg Piperacillin-tazobactam.
Or Carbapenems eg Imipenem or Meropenem.

Plus

Antipseudomonal flouroquinolone eg. Levofloxacin, ciprofloxacin.
OR Aminoglycoside eg. Amikacin, gentamycin.
OR Polymyxins eg. Colistin or Polymyxin B.

Plus

Anti-MRSA: Linezolid OR Vancomycin.

Assessment of Non-Responders

Wrong diagnosis

Atelectasis.
Pulmonary embolism.
ARDS.
Pulmonary hemorrhage.
Underlying disease.
Neoplasm.

Nebulizer or Inhaler to avoid systemic toxicity of Certain drugs if they are given together. e.g. Fluoroquinolones, Aminoglycosides (Amikacin & Gentamicin; Combination of both causes Nephropathy)