The Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) recently published a joint update to their nosocomial pneumonia guideline.1,2
About 11 years have passed since the first guideline was published, and so identifying key changes between the new guideline and the original might be difficult for some end users. In this article, I highlighted several key differences and updates related to antibiotic therapy.
First, the previous guideline included healthcare-associated pneumonia (HCAP) in the spectrum of hospital-acquired pneumonia (HAP) and ventilator-acquired pneumonia (VAP). This was done because patients with HCAP were thought to be at high risk for multidrug-resistant (MDR) pathogens due to exposure to pathogens within healthcare facilities. In the new guideline, HCAP is included under the guideline for community-acquired pneumonia because recent data3-7
showed that many patients are not at high risk for MDR organisms as previously thought and therefore should not be treated in the same manner as patients with HAP or VAP.
Second, additional risk factors for MDR pathogens are provided in the new guideline. These risk factors include the septic shock at time of VAP and acute respiratory distress syndrome or acute renal replacement therapy preceding VAP. All risk factors for HCAP have been removed.
Third, the previous guideline recommended the use of 2 empiric antipseudomonal agents for all patients at high risk for MDR pathogens. In contrast, the new guideline recommended two agents for patients with structural lung disease that increases the risk of gram-negative infection (ie, bronchiectasis or cystic fibrosis). In addition, the older guideline suggested considering two empiric antipseudomonal agents in patients with VAP with a risk factor for MDR pathogens, those in units where more than 10% of gram-negative isolates are resistant to an agent being considered for monotherapy, and those in an ICU where local antimicrobial susceptibility rates are not available. The authors believed that this would reduce patient harm, unnecessary exposure to broad-spectrum antibiotic coverage, and microbial resistance development. The guideline further recommends having a specific antibiogram for intensive care patients.
Fourth, the new guideline clearly recommends including empiric coverage for methicillin-susceptible Staphylococcus aureus
(MSSA) for VAP patients if coverage for methicillin-resistant S. aureus
was not indicated. The antibiotics suggested for these infections include piperacillin-tazobactam, cefepime, levofloxacin, imipenem, or meropenem.
Fifth, the new guideline recommends several therapeutic options and removes other options. For example, the new guideline does not include some antibiotics that were mentioned in the previous guideline as a possible option for empiric therapy, such as ampicillin/sulbactam, ceftriaxone, moxifloxacin, and ertapenem. This is because these agents do not have antipseudomonal activity, while all of the options included in the new guideline have activity against Pseudomonas aeruginosa
. In addition, the combination of both inhaled and systemic antibiotics is now recommended for patients with VAP because of gram-negative bacilli that are susceptible to only aminoglycosides or polymyxins.