Pneumonia - Community-Acquired Management

Prevention (Revamp)

Low-risk Community-acquired Pneumonia  

Most patients respond to treatment within 24-72 hours. The indicators of response to therapy include a decline of fever within 72 hours, return of temperature to normal within 5 days, and resolution of respiratory signs.  

Moderate-risk and High-risk Community-acquired Pneumonia  

Streamlining initial empiric broad-spectrum parenteral therapy to a single narrow-spectrum parenteral or oral agent based on available laboratory data is recommended as early as 24-72 hours following initiation of empirical treatment. The indications for streamlining antibiotic therapy include the following: 

• Less cough and normalization of respiratory rate
• Afebrile for >24 hours
• Blood cultures are negative or etiology is not a high-risk (virulent/resistant) pathogen
• No unstable comorbid condition or life-threatening complication (eg MI, CHF, complete heart block, new atrial fibrillation, supraventricular tachycardia)
• No obvious reason for continued hospitalization (eg hypotension, acute mental changes, BUN: creatinine ratio of >10:1, hypoxemia, metabolic acidosis, etc.)
• Able to initiate and maintain oral intake

Switching therapy to an oral agent will allow discharge from the hospital as early as the fourth day of hospitalization and will lead to cost savings. Blood and sputum cultures should be obtained in patients given empiric therapy for MRSA or Pseudomonas aeruginosa.  Agents should be de-escalated after two days if cultures are negative and with clinical improvement. Inpatient observation while receiving oral therapy is not necessary.

Poor Response to Treatment  

Major causes of antibiotic failure include a mismatch between the causative organism and agent used, a causative agent not covered by usual empirical treatment, and the presence of nosocomial superinfection pneumonia or complications (eg empyema).  Patients with poor response to treatment may do a follow-up chest X-ray or computed tomography (CT) scan and be reassessed for possible resistance to the antibiotics being given. In these patients, consideration should be given to other pathogens (eg Mycobacterium tuberculosis, viruses, parasites, or fungi) and other conditions (eg pneumothorax, cavitation and extension to previously uninvolved lobes, pulmonary edema, and acute respiratory distress syndrome [ARDS]).  Treatment should be revised based on the causative agents and sensitivity test results (pathogen-specific antimicrobial therapy).

• Streptococcus pneumoniae: Penicillin G, Amoxicillin
  • Alternative: Macrolide, second-third generation cephalosporin
• Haemophilus influenzae: Amoxicillin, second-third generation cephalosporin, Amoxicillin-clavulanate
  • Alternative: Fluoroquinolone
• Mycoplasma pneumoniae or Chlamydophila pneumoniae: Macrolide, tetracycline
  • Alternative: Fluoroquinolone
• Legionella sp: Fluoroquinolone, Macrolide (Clarithromycin, Azithromycin)
• Chlamydophila psittaci, Coxiella burnetti: Tetracycline
  • Alternative: Macrolide
• Pseudomonas aeruginosa: Antipseudomonal beta-lactam plus (Ciprofloxacin or Levofloxacin or aminoglycoside)
• Acinetobacter sp: Carbapenem
• Staphylococcus aureus: Antistaphylococcal penicillin if methicillin-susceptible; Vancomycin or Linezolid if methicillin-resistant
• Enterobacteriaceae: Extended-spectrum beta-lactamase producer (third generation cephalosporin, carbapenem)

Treatment Failure  

Treatment failure is generally defined as a lack of response or worsening of clinical status. Patients may show hemodynamic instability, impairment of respiratory function, the need for mechanical ventilation, radiographic progression, and appearance of new metastatic infectious foci.  

The management of treatment failure begins with the reassessment of the patient for possible resistance to antibiotics being given and considering the presence of other pathogens (eg Mycobacterium tuberculosis, viruses, parasites, or fungi). Repeat measurement of C-reactive protein (CRP) and repeat chest X-ray may be done if without any clinical improvement 3 days after initiation of therapy. In addition to microbiological diagnostic procedures, chest CT scan, thoracentesis, bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial biopsies, and chest X-ray should be considered. Follow-up chest X-ray should be done to identify pneumothorax, cavitation, and extension to previously uninvolved lobes, pulmonary edema, and acute respiratory distress syndrome. Reassess treatment accordingly thereafter.  

Criteria for Discharge  

Prior to discharge, it is important to review the patient’s status within 24 hours of planned discharge. During the assessment, patients should fulfill the following criteria:

• Temperature of 36-37.5°C
• Pulse rate of <100 beats/minute
• Respiratory rate of 16-24 breaths/minute
• Systolic blood pressure of >90 mmHg
• Blood oxygen saturation of >90%
• Ability to eat and take oral antibiotics
• Absence of active clinical or psychosocial problems requiring hospital stay 

Evaluation

Antibiotics should be initiated as soon as possible upon diagnosis of community-acquired pneumonia. When choosing antibiotics, local antimicrobial resistance should be considered. For patients with sepsis, refer to the management recommendations for sepsis (sepsis bundle). Among patients with recent antibiotic exposure, do not use antibiotics in the same class as the patient had been receiving previously.  

In patients with low severity, consider a 5-day single antibiotic course. Duration may be extended if patient is still symptomatic after 3 days of treatment. Dual antibiotic therapy and quinolones should be avoided in these patients.  

In patients with moderate-high severity, a 7- to a 10-day antibiotic course is recommended. Dual antibiotic therapy (Amoxicillin plus a macrolide) is recommended. Dual antibiotic therapy with a beta-lactamase stable beta-lactam plus a macrolide is recommended for high-severity community-acquired pneumonia patients. In patients with high-risk pneumonia, the parenteral route is recommended for all antimicrobial administration because the severity of the condition may result in a low perfusion state.  

Infection with anaerobes should also be considered as possible causative organisms in patients with a risk of aspiration. The addition of anaerobic antimicrobials to routine community-acquired pneumonia therapy should only be initiated if a lung abscess or empyema is suspected.  

In patients who tested positive for MRSA or Pseudomonas aeruginosa in the respiratory tract within the prior year, initiation of empiric therapy against MRSA or Pseudomonas aeruginosa is recommended in addition to standard community-acquired pneumonia antimicrobials. Empiric therapy for MRSA or Pseudomonas aeruginosa may be withheld in patients without prior colonization located in areas with very low prevalence.  

Empiric treatment for MRSA or Pseudomonas aeruginosa should only be started in patients with non-severe community-acquired pneumonia if locally validated risk factors are present. Treatment may be continued based on the published risk factors even without local etiological data. Culture results should be obtained after initiation to confirm the presence of MRSA or Pseudomonas aeruginosa.

Principles of therapy

Reference: The American Thoracic Society (ATS) and the Infectious Disease Society of America (IDSA) 2019 official clinical practice guideline on the diagnosis and treatment of adults with community-acquired pneumonia.
¹Macrolides: Azithromycin, Clarithromycin; Erythromycin for pregnant patients
²Cephalosporins: Cefpodoxime, Cefuroxime
³Respiratory fluoroquinolones: Gemifloxacin, Levofloxacin, Moxifloxacin
⁴Beta-lactams: Ampicillin/sulbactam, Cefotaxime, Ceftriaxone, Ceftaroline
⁵May start treatment in a patient with other risk factors (recent hospitalization with parenteral antibiotics and locally validated risk factors) only if with positive culture results
⁶If with risk factors for methicillin-resistant Staphylococcus aureus, may add treatment against methicillin-resistant Staphylococcus aureus if with positive rapid nasal polymerase chain reaction result and obtain cultures

Beta-lactams

Low-risk Community-acquired Pneumonia  

High-dose Amoxicillin or Amoxicillin/clavulanate (Co-amoxiclav) is preferred as it targets >93% of Streptococcus pneumoniae. Comorbidities or recent antimicrobial therapy increase the likelihood of infection with drug-resistant Streptococcus pneumoniae and enteric Gram-negative bacteria which may be treated using a combination of a beta-lactam and a macrolide. Second and third generation cephalosporins can be used as alternative antibiotic therapy for patients with stable co-morbid conditions; these are less active in vitro than high-dose Amoxicillin.

Moderate-risk and High-risk Community-acquired Pneumonia  

Parenteral nonpseudomonal beta-lactams with or without a beta-lactamase inhibitor are recommended. Some antibiotics from this class may also have anaerobic activity. Patients may be given either an extended macrolide or a respiratory quinolone. Recommended beta-lactams include penicillins, second- and third-generation cephalosporins, and carbapenems if with Pseudomonas aeruginosa risk. Combining non-pseudomonal beta-lactams with macrolides results in a significant reduction in mortality.   

Consider giving Oxacillin to patients shown or suspected to have lung abscesses, pneumatoceles, or pyothorax, in which Staphylococcus sp is a common etiologic organism. The best indicator of Staphylococcus aureus infection is the presence of Gram-positive cocci in clusters in a tracheal aspirate or in an adequate sputum sample. 

Clindamycin or Beta-lactam/Beta-lactamase Inhibitor

May consider adding empiric antibiotic agents Clindamycin or β-lactam/β-lactamase inhibitors in hospitalized patients with suspected aspiration pneumonia if lung abscess or empyema is suspected. Clindamycin may be used as an alternative to Linezolid or Vancomycin if the isolate is susceptible.

Lefamulin  

A newly approved pleuromutilin antibiotic that may be used as treatment for community-acquired bacterial pneumonia. Studies showed that the use of Lefamulin in hospitalized adult patients is non-inferior to Moxifloxacin

Macrolides  

Low-risk Community-acquired Pneumonia  

Macrolides and azalides may be better for patients with extrapulmonary physical findings, a feature of pneumonia caused by atypical pathogens. Macrolides may be considered if with <25% local pneumococcal resistance. It may also serve as an alternative for patients who are hypersensitive to Penicillin. Erythromycin is less active against Haemophilus influenzae. Azithromycin is preferred for outpatients with comorbidities (eg chronic obstructive pulmonary disease) because of Haemophilus influenzae.  

Moderate-risk and High-risk Community-acquired Pneumonia  

Combining macrolides with nonpseudomonal beta-lactams results in reduced mortality. Adding a macrolide to the antibiotic regimen benefits patients in areas with high prevalence of Legionella sp.

Quinolones with Anti-Pneumococcal Action (Respiratory Quinolones)

Low-risk Community-acquired Pneumonia   

May be used alone as an alternative regimen to combination therapy of beta-lactam with or without beta-lactamase inhibitor plus a macrolide in patients with comorbid illness.  

Moderate-risk to High-risk Community-acquired Pneumonia  

Alternative regimen to macrolides in the combination therapy with nonpseudomonal beta-lactam with or without beta-lactamase inhibitor, for patients without comorbid illnesses but with documented allergies, contraindications, or those unresponsive to macrolides. In areas with a high prevalence of pulmonary tuberculosis (TB), they are better reserved as potential second-line agents for the treatment of multidrug-resistant tuberculosis. However, quinolones may mask the clinical features of pulmonary TB and delay its diagnosis.

Tetracyclines

Low-risk to Moderate-risk Community-acquired Pneumonia  

Doxycycline may be used in low-risk and moderate-risk patients without comorbidities and with documented allergies, contraindications, or those unresponsive to treatment with macrolides and fluoroquinolones.  

Moderate-risk Community-acquired Pneumonia  

Omadacycline is a newly approved broad-spectrum antibiotic treatment option for adults with nonsevere community-acquired pneumonia, especially in the setting of tetracycline resistance with efficacy comparable to Moxifloxacin.

Other Treatments

Anti-influenza treatment (eg Oseltamivir, Zanamivir) is recommended for patients who are positive for influenza virus regardless of the site of care and should be given within 48 hours of symptom onset.

Duration of Treatment Based on Etiology

Serial procalcitonin measurement may be used as a guide for the determination of the duration of antibiotic therapy. In clinically stable patients, a drop in procalcitonin level from the peak by ≥80% and/or a fall below the cut-off indicates resolution of illness and earlier discontinuation of antibiotics.  

Low-risk Community-acquired Pneumonia  

A minimum of 5 days with a usual duration of 5-7 days for most cases of pneumonia of bacterial etiology is recommended. A 3-day course of oral therapy may be possible with azalides.  

Moderate-risk and High-risk Community-acquired Pneumonia 

Pneumonia - Community-Acquired_Management

Pharmacological therapy

Patient Education

Teach the patient to monitor temperature and sputum production and recognize worsening signs and symptoms and the onset of complications. Remind the patient to rest and drink plenty of fluids. Help the patient understand and comply with the medication regimen and diet.  

Explain the importance of vaccination in patients with recurrent infections. Inform the patient that a repeat chest X-ray is needed after recovery in patients at risk for lung cancer.  Instruct the patient about the use and cleaning of home respiratory equipment (eg mini-nebulizer) and remind the patient that nebulization is not recommended in patients with suspected or confirmed COVID-19 infection. Encourage the patient to be in a smoke-free environment or to quit smoking. 

Nonpharmacological

Pneumococcal and influenza vaccines are recommended for the prevention of community-acquired pneumonia. Both pneumococcal and influenza vaccines can be administered simultaneously at different sites without increasing side effects. There are no contraindications for pneumococcal or influenza vaccine use immediately after an episode of pneumonia.  

Pneumococcal Vaccine*  

There are 4 different types of pneumococcal vaccines. The 13-valent pneumococcal polysaccharide conjugate vaccine (PCV13), 15-valent pneumococcal polysaccharide conjugate vaccine (PCV15), and 23-valent pneumococcal polysaccharide vaccine (PPSV23) are recommended for adults. The 10-valent pneumococcal conjugate vaccine (PCV10), PCV13, and PCV15 are recommended for children.  

Pneumococcal vaccination is routinely recommended in adults who are ≥65 years, 19-64 years old who smoke cigarettes, with chronic heart disease (eg congestive heart failure, cardiomyopathy, but excluding hypertension), chronic lung disease (eg chronic obstructive lung disease, emphysema, asthma), chronic liver disease (eg liver cirrhosis), diabetes mellitus, and alcoholism. People living in nursing homes or other long-term care facilities should also be given pneumococcal vaccines.  

Immunocompromised conditions that require pneumococcal vaccination include B- or T-lymphocyte deficiency, complement deficiencies and phagocytic disorders (excluding chronic granulomatous disease), HIV infection (vaccine should be given as soon as possible), chronic renal failure and nephrotic syndrome, leukemia, Hodgkin lymphoma, generalized malignancy, multiple myeloma, patient who underwent solid organ transplantation, and iatrogenic immunosuppression (including long-term systemic corticosteroid and radiation therapy). Pneumococcal vaccination should be given at least 2 weeks before starting immunosuppressive therapy. Patients with anatomical or functional asplenia (eg sickle cell disease and other hemoglobinopathies, congenital or acquired asplenia, splenic dysfunction, and splenectomy) should be given pneumococcal vaccination at least 2 weeks before an elective splenectomy.  

For patients ≥19 years old with a cochlear implant and cerebrospinal fluid (CSF) leak, a single dose of PCV20 is recommended. Alternatively, PCV15 may be given first followed by PPSV23 after ≥8 weeks. If in this group of patients, only PPSV23 was given, PCV20 or PCV15 should be given ≥1 year after the PPSV23 administration. If only PCV13 was given, PCV20 should be given at least 1 year or PPSV23 should be given ≥8 weeks after PCV13 administration. If the patient was given PCV13 and 1 dose of PPSV23, PCV20 should be given ≥5 years after PPSV23 administration.  

PCV13 can be given to patients >50 years old to prevent pneumonia and other invasive pneumococcal diseases. Based on the recommendation made by the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention (CDC), for patients ≥65 years with indications for both PCV15 and PPSV23 vaccination with no history of any pneumococcal vaccination, PCV20 should be administered. Alternatively, PCV15 may be given first followed by the PPSV23 dose ≥1 year after PCV15 administration. PCV13 or PCV15 and PPSV23 should not be administered concurrently on the same visit. For patients who received PPSV23 vaccination only at any age, PCV15 or PCV20 should be given ≥1 year after the previous PPSV23 dose. If a patient was previously vaccinated with PCV13 only, PCV20 or PPSV23 should be given ≥1 year after the previous PCV13 dose. For patients with both PPSV23 and PCV13 doses given before age 65 years, PCV20 or PPSV23 should be given ≥5 years after the previous PPSV23 dose.  

Revaccination of PPSV23 at age >65 years is recommended 5 years after the last dose of PPSV23 for persons who have received PPSV23 before age 65 years. A second dose of PPSV23 given 5 years after the first dose is advised in persons 19-64 years old with functional or anatomical asplenia and for persons who are immunocompromised.  

Pneumococcal vaccine is not recommended for persons with a history of serious allergic reaction to a vaccine component, moderate or severe acute illness, and pregnancy.  

Pneumonia - Community-Acquired_Follow Up