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

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

References:

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