From the Guidelines
Community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP) differ primarily in their setting of acquisition, causative pathogens, and treatment approaches, with HAP generally carrying a higher mortality rate due to the resistant pathogens involved and the compromised state of hospitalized patients. The main difference between CAP and HAP lies in the setting where the infection is acquired, with CAP occurring in patients who have not been hospitalized or in a healthcare facility within the past 14 days, and HAP developing 48 hours or more after hospital admission 1.
Causative Pathogens
The causative pathogens also differ between CAP and HAP. CAP is typically caused by Streptococcus pneumoniae, Haemophilus influenzae, and atypical pathogens like Mycoplasma pneumoniae. In contrast, HAP often involves more resistant organisms like Pseudomonas aeruginosa, Klebsiella, Acinetobacter, and MRSA 1.
Treatment Approaches
Treatment approaches for CAP and HAP also vary. For mild-moderate CAP, treatment usually involves amoxicillin 1g three times daily for 5-7 days, or doxycycline 100mg twice daily if penicillin-allergic. More severe cases may require combination therapy with a beta-lactam plus a macrolide. HAP treatment, on the other hand, typically requires broader-spectrum antibiotics such as piperacillin-tazobactam 4.5g every 6 hours or cefepime 2g every 8 hours, often with vancomycin 15-20mg/kg every 8-12 hours if MRSA is suspected 1.
Diagnosis and Mortality
Proper diagnosis of CAP and HAP requires clinical assessment, chest imaging, and appropriate cultures to guide targeted therapy. HAP generally carries a higher mortality rate due to the resistant pathogens involved and the compromised state of hospitalized patients, with the crude mortality rate for HAP ranging from 30 to 70% 1.
Key differences between CAP and HAP include:
- Setting of acquisition: CAP occurs outside of the hospital, while HAP develops 48 hours or more after hospital admission
- Causative pathogens: CAP is typically caused by Streptococcus pneumoniae, Haemophilus influenzae, and atypical pathogens, while HAP often involves more resistant organisms like Pseudomonas aeruginosa, Klebsiella, Acinetobacter, and MRSA
- Treatment approaches: CAP treatment usually involves narrower-spectrum antibiotics, while HAP treatment requires broader-spectrum antibiotics
- Mortality rate: HAP generally carries a higher mortality rate due to the resistant pathogens involved and the compromised state of hospitalized patients.
From the FDA Drug Label
NOTE: Azithromycin should not be used in patients with pneumonia who are judged to be inappropriate for oral therapy because of moderate to severe illness or risk factors such as any of the following: patients with cystic fibrosis, patients with nosocomially acquired infections, patients with known or suspected bacteremia, patients requiring hospitalization, elderly or debilitated patients, or patients with significant underlying health problems that may compromise their ability to respond to their illness (including immunodeficiency or functional asplenia).
NOTE: Azithromycin should not be used in pediatric patients with pneumonia who are judged to be inappropriate for oral therapy because of moderate to severe illness or risk factors such as any of the following: patients with cystic fibrosis, patients with nosocomially acquired infections, patients with known or suspected bacteremia, patients requiring hospitalization, or patients with significant underlying health problems that may compromise their ability to respond to their illness (including immunodeficiency or functional asplenia).
The main difference between Community-Acquired Pneumonia (CAP) and Hospital-Acquired Pneumonia (HAP) is the setting in which the infection is acquired.
- CAP occurs in patients who are not hospitalized and have not recently been hospitalized, and is typically caused by bacteria such as Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.
- HAP, also known as nosocomial pneumonia, occurs in patients who are hospitalized, and is often caused by more resistant bacteria such as Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA). This distinction is important because it can affect treatment decisions, as patients with HAP may require more broad-spectrum antibiotics and closer monitoring due to the higher risk of complications and resistance to antibiotics 2.
From the Research
Community-Acquired Pneumonia (CAP) vs Hospital-Acquired Pneumonia (HAP)
- The provided studies focus on Community-Acquired Pneumonia (CAP), with no direct comparison to Hospital-Acquired Pneumonia (HAP) 3, 4, 5, 6, 7.
- CAP is defined as pneumonia acquired outside of the hospital setting, whereas HAP is acquired within the hospital setting, typically 48 hours or more after admission.
- The treatment strategies and antibiotic choices for CAP are discussed in the provided studies, including the use of beta-lactam monotherapy, beta-lactam-macrolide combination therapy, and fluoroquinolone monotherapy 3, 4, 6.
- The studies highlight the importance of empirical antibiotic treatment for CAP, covering both typical and atypical pathogens, and the need for accurate diagnosis and treatment algorithms to ensure effective treatment and minimize antibiotic resistance 4, 5, 7.
Key Differences
- The main difference between CAP and HAP lies in the setting in which the pneumonia is acquired, with CAP being community-acquired and HAP being hospital-acquired.
- The provided studies do not directly address the differences between CAP and HAP, but rather focus on the treatment and management of CAP.
- Further research would be needed to compare and contrast the two conditions, including their epidemiology, pathogenesis, and treatment strategies.