Guidance released for treating CAP in immunocompromised patients

The recommendations, based mainly on expert opinion, include general principles of empiric therapy and advice for specific pathogens, including methicillin-resistant Staphylococcus aureus and resistant gram-negative bacilli.

A multidisciplinary group of physicians recently released a guidance statement on treating immunocompromised patients who present to the hospital with community-acquired pneumonia (CAP).

Immunocompromised patients are often excluded from CAP guidelines in part because they require complex, individualized care, but the number of immunocompromised patients at risk for CAP is growing, the statement said. The statement's aim was to develop a unifying approach to initial management of immunocompromised patients in whom CAP is suspected. The authors reviewed the available literature and arrived at consensus on 21 recommendations. The statement was published by CHEST on June 16.

For general principles of empiric therapy, the authors suggest the following:

  • Immunocompromised patients with no additional risk factors for drug-resistant bacteria can receive initial empiric therapy targeting only the core respiratory pathogens.
  • Empiric therapy can be extended beyond core respiratory pathogens when 1) risk factors for drug-resistant organisms or opportunistic pathogens are present and 2) the delay in empiric antimicrobial therapy will increase the patient's risk for death.
  • Severe pneumonia can be used as an indication to start empiric therapy for resistant gram-positive and gram-negative organisms, followed by rapid de-escalation if no multidrug-resistant pathogen is identified.

Among the recommendations for specific pathogens, the authors suggest the following:

  • Initial empiric therapy to cover for methicillin-resistant Staphylococcus aureus (MRSA) should be started in patients who have a history of MRSA colonization or infection with MRSA in the previous 12 months.
  • Initial empiric therapy for immunocompromised patients should cover resistant gram-negative bacilli, including Pseudomonas aeruginosa, if there is a history of colonization or infection with a resistant gram-negative bacilli in the previous 12 months, previous hospitalization with exposure to broad-spectrum antibiotics, presence of a tracheostomy, neutropenia, or history of pulmonary comorbidity.
  • In patients with a recent history of colonization or infection with multidrug-resistant gram-negative bacilli, initial empiric therapy should cover the possibility of infection with colonizing multidrug-resistant gram-negative bacilli.
  • Empiric therapy should cover the possibility of pneumonia due to filamentous fungi such as Aspergillus in patients with cancer and chemotherapy with severe and prolonged neutropenia and radiographic nodular pattern surrounded by a halo of ground-glass attenuation and/or cavitation.

Additional recommendations cover CAP due to Pneumocystis jirovecii pneumonia, Mucorales, Nocardia, varicella zoster virus, cytomegalovirus, Mycobacterium tuberculosis, and parasites. The definition of the population, sites of care, likely pathogens, and microbiological workup are also addressed.

“Despite our suggestions of empirical therapy for specific pathogens in specific situations, we stress the importance of making a concerted effort to establish a rapid and accurate etiologic diagnosis and to de-escalate complex therapies once a presumptive pathogen is properly ruled out,” the authors wrote. “It is also important to consider local susceptibility patterns when selecting empiric therapy.” They emphasized that evidence in immunocompromised patients is lacking and that their recommendations are based mainly on expert opinion. “Because immunocompromised patients have been excluded from prospective randomized studies of CAP treatment, there is an urgent need to generate scientific evidence in this field,” they wrote.

A story in the January ACP Hospitalist reviewed new guidelines for CAP as well as changes in management.