Changes in Therapy Recommendations in the 2019 ATS/IDSA Guidelines for Community-Acquired Pneumonia


This article highlights some key updates to the antimicrobial therapy recommendations in the updated community-acquired pneumonia guidelines.

After about 12 years, a joint update of the community-acquired pneumonia (CAP) guidelines was recently published by the American Thoracic Society and the Infectious Diseases Society of America.1,2 This article highlights some key updates to the antimicrobial therapy recommendations.

First, the term health care-associated pneumonia (HCAP) was introduced in the 2005 guidelines for hospital-acquired, ventilator-associated, and health care-associated pneumonia as it was thought some patients who acquired pneumonia in the community with certain risk factors for multidrug-resistant bacteria (e.g., living in nursing homes) should be treated similarly to patients with nosocomial pneumonia.3-8 In the new guidelines, the term HCAP is clearly eliminated and it is recommended that these patients be treated as CAP patients without covering methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa unless they meet criteria for locally validated risk factors for antibiotic-resistant bacteria.

Second, the updated guidelines have a number of new culturing and diagnostic recommendations. A new strong recommendation is made for ordering sputum and blood cultures for patients started empirically on anti-MRSA or antipseudomonal antibiotics. This recommendation can result in more de-escalation when the culture findings are negative for these bacteria. The guidelines also recommend against the use of routine follow-up x-rays if patients are improving. In addition, it is advised that procalcitonin should not be used for guidance of antibiotic initiation. Lastly, urinary antigen testing for Streptococcus pneumoniae and Legionella is also discouraged.

Third, antibiotic choices for outpatients have slightly changed. The new guidelines recommend amoxicillin as the first-line agent for outpatients without comorbidities or risk factors for resistant bacteria. Amoxicillin was not listed as an option in the previous version of the guidelines. Despite lacking atypical coverage, the authors pointed out its documented efficacy and safety in several studies. Previously, macrolides were recommended as first-line antibiotics, but the new guideline lists macrolides as alternative options due to therapy failures in patients with macrolide-resistant S pneumoniae and increasing macrolide resistance in United States.9,10 While azithromycin and clarithromycin remain macrolide choices, erythromycin has been removed as a potential CAP therapy. In other antibiotic changes, amoxicillin (without clavulanate) and ampicillin (without sulbactam) are no longer recommended for patients with comorbidities because they do not cover β-lactamase producing Haemophilus influenzae, Moraxella catarrhalis, methicillin-susceptible S aureus (MSSA), and certain gram-negative bacilli. These patients may be more vulnerable to poor outcomes with inadequate empiric therapy.

Fourth, there are also notable changes in the recommended antibiotics for inpatients. For inpatients without risk factors for P. aeruginosa, the β-lactam options have been updated. Intravenous cefuroxime has been removed, while ceftaroline has been added. Ceftaroline was not approved during the previous guideline period. In clinical trials, ceftaroline showed superior clinical outcomes compared to ceftriaxone in CAP caused by S pneumoniae and MSSA.11 For inpatients with P aeruginosa risk factors, the previous guidelines recommended double gram-negative coverage, but the new guideline recommends 1 antipseudomonal β-lactam.

Fifth, the new guidelines recommend against routinely adding coverage against anaerobes in suspected aspiration pneumonia unless empyema or lung abscess is present. Several more recent studies did not find a major role for anaerobes in etiology; therefore, adding anaerobic coverage might cause harm without added benefit.12,13

Sixth, the new guideline recommends against routine corticosteroid use for CAP. Seventh, withholding empiric antibiotic therapy is not recommended, but early discontinuation can be considered in CAP patients who have test positive for influenza.

Finally, the guideline states that newer antibiotics, such as lefamulin and omadacycline, require further data. The randomized controlled trials for these agents in CAP were published after the guidelines were released, and therefore did not make it into the official recommendations. Individual clinicians and institutions will have to determine where the newer agents fit into their local treatment algorithms.

In conclusion, the updated guidelines have a number of changes compared to its predecessor. A summary of these changes is provided in the table. Clinicians are encouraged to review and adopt these guidelines in clinical practice.

ATS indicates American Thoracic Society; CAP, community-acquired pneumonia; FDA, US Food and Drug Administration; HAP, hospital-acquired pneumonia; HCAP, healthcare-associated pneumonia; IDSA, Infectious Diseases Society of America; IV, intravenous; VAP, ventilator-acquired pneumonia.

Eljaaly is an assistant professor and infectious disease pharmacist at Faculty of Pharmacy, King Abdulaziz University, and an honorary research fellow at University of Arizona. He is a member of social media committee in both the Society of Infectious Diseases Pharmacists (SIDP) and Infectious Diseases Practice and Research Network of the American College of Clinical Pharmacy. He is also a member of Contagion®’s Editorial Advisory Board. His twitter handle is @khalideljaaly.

*Eljaaly is a member of SIDP


  1. Metlay JP, Waterer GW, Long AC, et al. Diagnosis and treatment of adults with community-acquired pneumonia: An official clinical practice guidelines of the American Thoracic Society and the Infectious Diseases Society of America. Am J Respir Crit Care Med. 2019;200(7):e45-e67. doi: 10.1164/rccm.201908-1581ST.
  2. Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007;44(Suppl 2):S27—72. Doi: 10.1086/511159.
  3. American Thoracic Society; Infectious Diseases Society of America. Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. Am J Respir Crit Care Med. 2005;171(4):388-416. doi: 10.1164/rccm.200405-644ST.
  4. Chalmers JD, Rother C, Salih W, Ewig S. Healthcare-associated pneumonia does not accurately identify potentially resistant pathogens: a systematic review and meta-analysis. Clin Infect Dis. 2014;58(3):330-339. doi: 10.1093/cid/cit734.
  5. Gross AE, Van Schooneveld TC, Olsen KM, et al. Epidemiology and predictors of multidrug-resistant community-acquired and health care-associated pneumonia. Antimicrob Agents Chemother. 2014;58(9):5262-68. doi: 10.1128/AAC.02582-14.
  6. Yap V, Datta D, Metersky ML. Is the present definition of health care-associated pneumonia the best way to define risk of infection with antibiotic-resistant pathogens? Infect Dis Clin North Am. 2013;27(1):1-18. doi: 10.1016/j.idc.2012.11.002.
  7. Jones BE, Jones MM, Huttner B, et al. Trends in antibiotic use and nosocomial pathogens in hospitalized veterans with pneumonia at 128 medical centers, 2006-2010. Clin Infect Dis. 2015;61(9):1403-1410. doi: 10.1093/cid/civ629.
  8. Valles J, Martin-Loeches I, Torres A, et al. Epidemiology, antibiotic therapy and clinical outcomes of healthcare-associated pneumonia in critically ill patients: a Spanish cohort study. Intensive Care Med. 2014;40(4):572-581. doi: 10.1007/s00134-014-3239-2.
  9. Lonks JR, Garau J, Gomez L, et al. Failure of macrolide antibiotic treatment in patients with bacteremia due to erythromycin-resistant Streptococcus pneumoniae. Clin Infect Dis. 2002;35:556—564. doi: 10.1086/341978.
  10. Daneman N, McGeer A, Green K, Low DE; Toronto Invasive Bacterial Diseases Network. Macrolide resistance in bacteremic pneumococcal disease: pneumococcal disease: implications for patient management. Clin Infect Dis. 2006;43:432—438. doi: 10.1086/505871
  11. Eljaaly K, Wali H, Basilim A, et al. Clinical cure with ceftriaxone versus ceftaroline or ceftobiprole in the treatment of staphylococcal pneumonia: a systematic review and meta-analysis. Int J Antimicrob Agents. 2019; doi:10.1016/j.ijantimicag.2019.05.023.
  12. El-Solh AA, Pietrantoni C, Bhat A, et al. Microbiology of severe aspiration pneumonia in institutionalized elderly. Am J Respir Crit Care Med. 2003;167:1650—1654. doi: 10.1164/rccm.200212-1543OC
  13. Marik PE, Careau P. The role of anaerobes in patients with ventilator-associated pneumonia and aspiration pneumonia: a prospective study. Chest. 1999;115:178—183. doi: 10.1378/chest.115.1.178
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