What changes should I consider in my treatment of hospitalized patients with community-acquired pneumonia (CAP) in light of the 2019 guidelines of the American Thoracic society (ATS) and Infectious Diseases Society of America (IDSA)?

Compared to 2007,1 the 2019 ATS/IDSA guidelines2 propose changes in at least 4 major areas of CAP treatment in inpatients, with 2 “Do’s” and 2 “Dont’s”:

  • Do select empiric antibiotics based on severity of CAP and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (see related pearl on P4P)
  • Do routinely treat CAP patients who test positive for influenza with standard CAP antibiotics
  • Don’t routinely provide anaerobic coverage in aspiration pneumonia (limit it to empyema and lung abscess) (see related pearl on P4P)
  • Don’t routinely treat CAP with adjunctive corticosteroids in the absence of refractory shock

β-lactam plus macrolide is recommended for both non-severe and severe CAP.  β-lactam plus respiratory fluoroquinolone is an alternative regime in severe CAP, though not endorsed as strongly as β-lactam plus macrolide therapy (low quality of evidence).  Management per CAP severity summarized below:

  • Non-severe CAP
    • β-lactam (eg, ceftriaxone, cefotaxime, ampicillin-sulbactam and newly-added ceftaroline) plus macrolide (eg, azithromycin, clarithromycin) OR respiratory fluoroquinolone (eg, levofloxacin, moxifloxacin)
    • In patients at risk of MRSA or P. aeruginosa infection (eg, prior isolation of respective pathogens, hospitalization and parenteral antibiotics in the last 90 days or locally validated risk factors—HCAP has been retired), obtain cultures/PCR
    • Hold off on MRSA or P. aeruginosa coverage unless culture/PCR results return positive.
  • Severe CAP
    • β-lactam plus macrolide OR β-lactam plus respiratory fluoroquinolone (see above)
    • In patients at risk of MRSA or P. aeruginosa infection (see above), obtain cultures/PCR
    • Add MRSA coverage (eg, vancomycin or linezolid) and/or P. aeruginosa coverage (eg, cefepime, ceftazidime, piperacillin-tazobactam, meropenem, imipenem) if deemed at risk (see above) while waiting for culture/PCR results

Duration of antibiotics is for a minimum of 5 days for commonly-targeted pathogens and a minimum of 7 days for MRSA or P. aeruginosa infections, irrespective of severity or rapidity in achieving clinical stability.

For patients who test positive for influenza and have CAP, standard antibacterial regimen should be routinely added to antiinfluenza treatment.

For patients suspected of aspiration pneumonia, anaerobic coverage (eg, clindamycin, ampicillin-sulbactam, piperacillin-tazobactam) is NOT routinely recommended in the absence of lung abscess or empyema.

Corticosteroids are NOT routinely recommended for non-severe (high quality of evidence) or severe (moderate quality of evidence) CAP in the absence of refractory septic shock.

Related pearls on P4P:

2019 CAP guidelines on diagnostics:                                        https://pearls4peers.com/2020/02/14/what-changes-should-i-consider-in-my-diagnostic-approach-to-hospitalized-patients-with-community-acquired-pneumonia-cap-in-light-of-the-2019-guidelines-of-the-american-thoracic-society-ats-and-inf/ 

Anerobic coverage of aspiration pneumonia: https://pearls4peers.com/2019/07/31/should-i-routinely-select-antibiotics-with-activity-against-anaerobes-in-my-patients-with-presumed-aspiration-pneumonia/

References

  1. Mandell LA, Wunderink RG, Anzueto A. Infectious Disease Society of America/American Thoracic Society Consensus Guidelines on the Management guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis 2007;44:S27-72. https://www.ncbi.nlm.nih.gov/pubmed/17278083
  2. Metlay JP, Waterer GW, Long AC, et al. Diagnosis and treatment of adults with community-acquired pneumonia. Am J Respir Crit Care Med 2019;200:e45-e67. https://www.ncbi.nlm.nih.gov/pubmed/31573350

 

What changes should I consider in my treatment of hospitalized patients with community-acquired pneumonia (CAP) in light of the 2019 guidelines of the American Thoracic society (ATS) and Infectious Diseases Society of America (IDSA)?

What is the sensitivity of nose swabs in detecting methicillin-resistant Staphylococcus aureus (MRSA) pneumonia?

In MRSA pneumonia, the sensitivity of nasal swab PCR may vary from as low as 24.2% to 88% (1-3). A 2018 meta-analysis found an overall sensitivity of 70.9% (community-acquired pneumonia/healthcare-associated pneumonia [HCAP] 85%, ventilator-associated pneumonia 40%) with overall negative predictive value of 96.5% (based on an overall MRSA pneumonia prevalence of 10%) (4). 

A single center  study involving  patients with possible HCAP and a low clinical pulmonary infection score (CPIS) — for whom antibiotics may not be necessary anyway (5)—suggested that discontinuation of empiric vancomycin in patients without an adequate respiratory culture and a negative nose and throat culture may be reasonable (6).

However, a prospective study of ICU patients concluded that “clinicians cannot reliably use the results of initial negative MRSA nasal swab results to withhold empirical MRSA coverage from patients who otherwise are at risk for MRSA infection” (3).

The previously cited 2018 meta-analysis study (4) cautions against use of MRSA screening in patients with structural lung disease (eg, cystic fibrosis or bronchiectasis) because colonization may be more frequent in the lower respiratory tract in these patients and screening tests may therefore be discordant (4).

Collectively, the available data suggest that it is reasonable to use a negative MRSA screen to help exclude pneumonia due to this pathogen in patients in whom MRSA infection is not highly suspected or those who are not severely ill.

 

References

  1. Rimawi RH, Ramsey KM, Shah KB, et al. Correlation between methicillin-resistant Staphylococcus aureus nasal sampling, and S. aureus pneumonia in the medical intensive care unit. Infect Control Hosp Epidemiol 2014;35:590-92. https://www.ncbi.nlm.nih.gov/pubmed/24709733
  2. Dangerfield B, Chung A, Webb B, et al. Predictive value of methicillin-resistant Staphylococcus aureus (MRSA) nasal swab PCR assay for MRSA pneumonia. Antimicrob Agents Chemother 2014;58:859-64. https://www.ncbi.nlm.nih.gov/pubmed/24277023
  3. Sarikonda KV, Micek ST, Doherty JA, et al. Methicillin-resistant Staphylococcus aureus nasal colonization is a poor predictor of intensive care unit-acquired methicillin-resistant Staphylococcus aureus infections requiring antibiotic treatment. Crit Care Med 2010;38:1991-1995. https://www.ncbi.nlm.nih.gov/pubmed/20683260
  4. Parente DM Cunha CB Mylonakis E et al. The clinical utility of methicillin-resistant Staphylococcus aureus (MRSA) nasal screening to rule out MRSA pneumonia: A diagnostic meta-analysis with antimicrobial stewardship implications. Clin Infect Dis 208;67:1-7.
  5. Napolitano LM. Use of severity scoring and stratification factors in clinical trials of hospital-acquired and ventilator-associated pneumonia. Clin Infect Dis 2010;51:S67-S80. https://www.ncbi.nlm.nih.gov/pubmed/20597675
  6. Boyce JM, Pop O-F, Abreu-Lanfranco O, et al. A trial of discontinuation of empiric vancomycin therapy in patients with suspected methicillin-resistant Staphylococcus aureus health care-associated pneumonia. Antimicrob Agents Chemother 2013;57:1163-1168. http://aac.asm.org/content/57/3/1163.full.pdf
What is the sensitivity of nose swabs in detecting methicillin-resistant Staphylococcus aureus (MRSA) pneumonia?