pneumonia%20-%20hospital-acquired
PNEUMONIA - HOSPITAL-ACQUIRED
Hospital-acquired pneumonia (HAP) is defined as pneumonia occurring ≥48 hours after admission and excluding any infection that is incubating at the time of admission.
Ventilator-associated pneumonia (VAP) is described as pneumonia occurring >48-72 hours after endotracheal intubation and within 48 hours after removal of endotracheal tube.
Early-onset HAP or VAP is the pneumonia occurring within the first 4 days of hospitalization that may be cause by antibiotic-sensitive bacteria that usually carries a better diagnosis.
Late-onset HAP or VAP is the pneumonia occurring after ≥5 days. It is likely caused by multidrug-resistant pathogens associated with increased mortality and morbidity.

Principles of Therapy

Initiation of Empiric Therapy 

  • Antibiotic therapy should be started within 4 hours after diagnosis of hospital-acquired pneumonia (HAP) has been established
  • Prompt initiation of appropriate initial antibiotic therapy can decrease mortality
  • When deciding to start empiric therapy, treatment should be microbiologically-defined rather than empiric therapy-based
  • All patients w/ HAP & ventilator-associated pneumonia (VAP) should be treated initially w/ intravenous (IV) therapy, but switch to oral therapy may be considered in some patients who are responding to therapy
  • Initial treatment of healthcare-associated pneumonia (HCAP) should be similar to that of HAP & VAP since spectrum of pathogens closely resemble late-onset HAP & VAP

Choice of Antibiotics for Empiric Therapy

  • Empiric choice of antibiotic agents should take into consideration the local microbiology, availability, cost & formulary restrictions
    • Initial empiric therapy should be adapted to local patterns of antibiotic resistance & when possible each ICU should collect this information on a regular basis
  • Empiric therapy also needs to take into consideration what therapies the patient has received within the last 2 weeks
    • If patient has received antibiotics recently for a different infection, therapy should utilize an agent from a different antibiotic class for resistance is predicted by recent antibiotic exposure
  • An antibiotic course of 5-10 days is recommended for patients w/ confirmed HAP
  • Not only should appropriate antibiotics be used, they should be used at the optimum doses & correct route of administration
  • A major risk factor for mortality & increasing length of hospital stay is the administration of inappropriate antibiotics

Pharmacotherapy

Empiric Therapy in Patients w/ No Risk Factors for Multidrug-resistant (MDR) Pathogens
  • Narrow-spectrum antibiotics are recommended for patients w/ low-risk & early-onset HAP/VAP
Possible Pathogens
  • Streptococcus pneumoniae
    • Local resistance patterns should be followed because the frequency of Penicillin-resistant & multidrug- resistant S pneumoniae is increasing
    • An aminopenicillin at appropriate dose remains the treatment of choice for most Penicillin-resistant S pneumoniae w/ MIC ≤2 mcg/mL
  • Other potential pathogens
    • Haemophilus influenzae, Methicillin-sensitive Staphylococcus aureus (MSSA)
    • Gram-negative bacilli (eg Escherichia coli, Klebsiella pneumoniae, Enterobacter sp, Proteus sp, Serratia marcescens)
Early-onset hospital-acquired pneumonia (HAP)
  • Patients w/ early-onset HAP without risk factors for MDR organisms will likely respond to monotherapy w/ 1 of the following agents:
    • Beta-lactam/beta-lactamase inhibitor combinations (eg Piperacillin/tazobactam)
    • Nonpseudomonal 3rd generation cephalosporins (eg Ceftriaxone, Cefotaxime, Cefepime or Cefpirome)
    • Carbapenems without antipseudomonal activity (eg Ertapenem, Imipenem, Meropenem)
    • Quinolones (eg Levofloxacin or Moxifloxacin)
  • Patients who have allergy to beta-lactam agents may be given quinolone alone or monobactam plus Clindamycin
  • If combination therapy is indicated, quinolone or 3rd generation cephalosporins plus macrolide may be given
  • If MSSA is confirmed, may consider treatment w/ Oxacillin, Nafcillin, or Cefazolin
Early-onset ventilator-associated pneumonia (VAP)
  • The following agents are recommended in patients w/ early-onset VAP without risk factors for MDR organisms:
    • Antipseudomonal 4th generation cephalosporins
      • Cefepime & Cefpirome are more resistant to some beta-lactamases
    • Carbapenems w/ antipseudomonal activity (eg Imipenem or Meropenem)
    • Antipseudomonal beta-lactam/beta-lactamase inhibitors (eg Piperacillin/tazobactam)
    • Quinolones (eg Levofloxacin)
  • If combination therapy is indicated, the following are recommended: Quinolones or aminoglycosides w/ or without glycopeptides (eg Vancomycin or Teicoplanin) or Linezolid
    • Some authorities recommend beta-lactam agent & aminoglycoside combination regimen based on improved survival rate
  • If L pneumophila is suspected, a quinolone should be included rather than an aminoglycoside
  • If MSSA is confirmed, may consider treatment w/ Oxacillin, Nafcillin, or Cefazolin
Empiric Therapy in Patients w/ Risk Factors for Multidrug-resistant (MDR) Pathogens
  • Broad-spectrum antibiotics w/ activity against MDR pathogens are recommended for patients w/ high risk & early-onset HAP/VAP
  • Those at risk for the below organisms should initially receive a combination of broad-spectrum coverage
    • This will decrease the risk of inappropriate antibiotic therapy
  • Concurrent treatment w/ 2-3 drugs should be considered in patients w/ late-onset VAP
Possible Pathogens
  • All the pathogens listed in section Empiric Therapy in Patients w/ No Risk Factors for MDR Pathogens are possible causative organisms
Multidrug-resistant (MDR) pathogens
  • Pseudomonas aeruginosa, K pneumoniae, Acinetobacter sp, & Stenotrophomonas maltophilia
  • Extended-spectrum beta-lactamase-producing (ESBL) Enterobacteriaceae
  • MRSA should be considered if MRSA risk factors (eg antibiotic therapy prior to onset of pneumonia, prolonged hospital stay) are present, presence of severe pneumonia/sepsis &/or if there is high local incidence
  • Legionella pneumophila
Late-onset Hospital-acquired Pneumonia (HAP) & Ventilator-associated Pneumonia (VAP)
  • The following agents are given as primary agents in patients w/ late-onset HAP & VAP w/ risk factors for MDR organisms:
    • Antipseudomonal carbapenems (eg Imipenem or Meropenem)
    • Antipseudomonal beta-lactam/beta-lactamase inhibitors (eg Piperacillin/tazobactam)
    • Antipseudomonal cephalosporins: 3rd & 4th generation (eg Cefepime, Ceftazidime)
      • Recommended only in patients w/ late-onset HAP
    • Antipseudomonal quinolones (eg Ciprofloxacin or Levofloxacin)
    • Aztreonam may be considered if w/ treatment failure w/ other agents
  • If combination therapy is indicated, aminoglycosides (eg Amikacin, Gentamicin or Tobramycin) may be considered as secondary agents
  • Glycopeptides (eg Vancomycin, Telavancin) or Linezolid may be added in the regimen or as a 3rd drug if patient requires coverage for possible Methicillin-resistant S aureus (MRSA) pneumonia
  • 2 antipseudomonal agents from different classes are recommended if patient is at increased risk for antibiotic resistance, w/ >10% resistance during drug sensitivity testing, or an ICU patient
Specific Pathogens

Suspected Pseudomonal Infection

  • Empiric treatment should include an antipseudomonal beta-lactam or carbapenem plus a quinolone or an aminoglycoside especially in high-risk patients
  • Monotherapy based on susceptibility test is preferred in HAP/VAP patients w/ pseudomonal infection without comorbidities rather than combination therapy 
  • Choice of specific agents if Pseudomonas sp is found should be based on the results of sensitivity testing
  • Pseudomonas sp can rapidly develop resistance to all classes of antibiotics & resistance develops in 30-50% of patients who receive monotherapy
    • Evidence is lacking to show that this does not occur when combination therapy is used but there is limited data showing patients w/ Pseudomonas sp bacteremia are less likely to die when combination therapy is used
  • Polymyxins B or E may be given as an alternative drug if patient remains unresponsive
Acinetobacter sp
  • Acinetobacter sp have native resistance to many classes of antibiotics
  • Carbapenems, Sulbactam (eg Ampicillin/sulbactam or Cefoperazone/sulbactam) & Polymyxins B or E (eg Colistin) tend to be the most consistently effective agents
    • Carbapenem-resistant clones can be a problem & therefore, optimal dosing should be used
    • IV Polymyxins (eg Colistin, Polymyxin B) are recommended for HAP/VAP patients w/ carbapenem-resistant strains; adjunctive inhaled Colistin may also be considered
  • Combination therapy of Imipenem plus Ampicillin/sulbactam or Sulbactam alone is recommended
  • Acinetobacter sp; however, Netilmicin has been shown to be effective in 50% of strains based on an Asian study
Extended-spectrum beta-lactamases (ESBL) Enterobacteriaceae
  • Carbapanems are generally a reliable choice
  • Tigecycline is effective against ESBL strains of K pneumoniae & E coli
  • Piperacillin/tazobactam has been proven to be highly active in vitro against K pneumoniae & E coli
  • Cephalosporin susceptibility is variable, therefore 3rd & 4th generation cephalosporins should not be used as monotherapy if this organism is suspected
    •  If Enterobacter sp is suspected, 3rd generation cephalosporins should be avoided because of possible emergence of resistance during treatment
  • If L pneumophila is suspected, antibiotic regimen should include a macrolide (eg Azithromycin) or quinolone (eg Ciprofloxacin or Levofloxacin) rather than an aminoglycoside
Methicillin-resistant Staphylococcus aureus (MRSA)
  • Vancomycin or Linezolid is recommended as1st-line agent for MRSA
  • Linezolid has been shown to have comparable or superior efficacy to Vancomycin in patients w/ HAP
  • Telavancin may be considered if Vancomycin & Linezolid are unavailable or w/ treatment failure but benefitsshould outweigh the risk
Digital Edition
Asia's trusted medical magazine for healthcare professionals. Get your MIMS Respirology - Malaysia digital copy today!
Sign In To Download
Editor's Recommendations
Most Read Articles
4 days ago
In patients with type 2 diabetes, obesity may be protective against vision-threatening diabetic retinopathy, a recent Korea study has shown.
10 Jun 2019
Atrial fibrillation (AF) carries an excess risk of stroke recurrence independent of comorbidity with and heart failure (HF), while HF without AF also poses a significant risk of recurrence, a study has shown.
Roshini Claire Anthony, 3 days ago

Men with metastatic hormone-sensitive prostate cancer (mHSPC) who receive testosterone suppression therapy may have a better survival outcome with the addition of enzalutamide over other non-steroidal anti-androgen (NSAA) therapies, according to the phase III ENZAMET* trial.

07 Jun 2019
Low-dose aspirin therapy does not confer significant benefits to elderly patients with hypertension, but treatment appears to increase the risk of haemorrhagic events, suggest a Japan study.