MPA | Pharmacy News

Matt Rico, Pharm.D., PGY1 pharmacy practice resident at Ascension Genesys Hospital, Grand Blanc

In fall 2019, the American Thoracic Society (ATS) and Infectious Diseases Society of America (IDSA) released a long-anticipated update to the community-acquired pneumonia (CAP) guidelines, the first update since 2007.1 These recommendations come at an opportune time as recent literature from Vaughn and colleagues suggests that two-thirds of patients in the 43-hospital network, (Michigan Hospital Medicine Safety Consortium) receive excess antibiotic therapy for CAP.2 

Regarding the classification of CAP, the guidelines strongly recommend the abandonment of the term healthcare-associated pneumonia (HCAP), as current evidence has not shown that the risk factors for HCAP predict high prevalence of antibiotic-resistant pathogens. Instead, the guidelines adhere to treatment recommendations for non-severe or severe CAP. Severe CAP patients must meet at least one major (septic shock with need for vasopressors or respiratory failure requiring mechanical ventilation) or at least three minor criteria (multilobar infiltrates, confusion/disorientation, respiratory rate ≥ 30 breaths/min, etc.) for diagnosis.1 

Regarding other diagnostic recommendations, the new guidelines provide a strong recommendation to only obtain sputum and blood cultures in select inpatients, including those with severe CAP, history of prior methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa infection, and patients who have been hospitalized and required parenteral antibiotics in the previous 90 days. Routine testing for pneumococcal and Legionella urinary antigens are only recommended in patients with severe CAP or if indicated by epidemiological factors for Legionella. Additionally, the guidelines strongly recommend that empiric antibiotic therapy is started with clinical suspicion/radiographic evidence of CAP regardless of serum procalcitonin.1 

Regarding treatment recommendations, there have been changes in the recommended outpatient antimicrobial treatment regimens. The guidelines now strongly recommend high-dose amoxicillin or doxycycline in adults with no comorbidities or risk factors for MRSA or P. aeruginosa infections due to the proven efficacy of amoxicillin for inpatient CAP. However, macrolides are now only conditionally recommended (azithromycin or clarithromycin) in these patients if there is < 25 percent local pneumococcal resistance. If an adult has comorbidities (chronic heart, lung, liver or renal disease; diabetes mellitus, malignancy, etc.), then combination therapy is now strongly recommended with amoxicillin/clavulanate (previously included amoxicillin, as well) or a cephalosporin (cefpodoxime or cefuroxime) plus a macrolide or doxycycline. Respiratory fluoroquinolones, such as levofloxacin, remain a strong recommendation for monotherapy.1 

For inpatient treatment, combination therapy with a β-lactam and a macrolide or monotherapy with a respiratory fluoroquinolone remains the treatment of choice for non-severe CAP. Though some literature published since the previous guideline update raised questions of the possibility of β-lactam monotherapy, the guidelines continue to recommend combination therapy citing evidence of a mortality benefit. In the previous guidelines, β-lactam/macrolide and β-lactam/respiratory fluoroquinolone regimens were given equal weight for severe CAP, but recent literature shows there may be an increased mortality risk with β-lactam/respiratory fluoroquinolone regimens. However, due to the low quality of evidence, both regimens remain strong recommendations for severe CAP. Additionally, ceftaroline is now among the recommended β-lactam agents, while intravenous cefuroxime is no longer listed. MRSA and P. aeruginosa coverage is recommended only in patients with prior respiratory isolation or recent hospitalization with parenteral antibiotics and locally validated risk factors for these pathogens. If there is a concern for aspiration pneumonia, the guidelines now provide a conditional recommendation to not routinely include anaerobic coverage unless a lung abscess or empyema is suspected, as recent evidence shows that anaerobes are uncommon in this patient population.1 

Regardless of the selected treatment, antibiotic therapy is still recommended for five days or seven days for MRSA and P. aeruginosa.1 Treatment duration should be a primary focus in health systems, as Vaughn and colleagues found that patients treated with excess duration of antibiotics while hospitalized did not have lower rates of death, readmission, emergency department visits or Clostridioides difficile infections. Transition from the inpatient to outpatient setting proved to contribute to excess days of therapy, where nearly 50 percent of total days of antibiotics and 93 percent of excess days of antibiotics were found, respectively.2 

While the previous guidelines did not mention corticosteroid use, it is now recommended to withhold from using these agents in patients with non-severe CAP. There is limited data to show mortality benefit in patients with severe CAP along with inconsistent definitions of disease severity in available literature, leading to a conditional recommendation against routine use.1 

In conclusion, the updated guidelines offer several new and revised recommendations for the management of community-acquired pneumonia. There is hope that these updates will provide needed guidance as health systems continue to work to find ways to optimize treatment of this common infectious disease.


  1. Metlay JP, Waterer GW, Long AC, et al. Diagnosis and Treatment of Adults with Community-acquired Pneumonia. Am J Respir Crit Care Med. Oct 2019. 200(7):e45-67.
  2. Vaughn VM, Flanders SA, Snyder A, et al. Excessive Antibiotic Treatment Duration and Adverse Events in Patients Hospitalized with Pneumonia. Ann Intern Med. 2019(171):153-63. 

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