Several risks factors have been identified as increasing the likelihood of immunocompetent patients developing pneumonia tied to drug-resistant pathogens. Female sex was reported to be a dominant risk factor, followed by a recent hospitalization.
A group of researchers recently proposed a new acronym, PES pathogens, to identify drug-resistant pathogens that are often found associated with community-acquired pneumonia, together with its risk factors. The PES pathogens include Pseudomonas aeruginosa, Enterobacteriaceae extended-spectrum beta-lactamase-positive, and methicillin-resistant Staphylococcus aureus (MRSA).
Now, another team evaluated the presence of PES pathogens in immunocompetent patients (i.e., patients capable of developing an immune response) with pneumonia, intending to validate the PES pathogens concept. To do this, the researchers performed a retrospective analysis of a prospective observational study involving 1,559 pneumonia patients. The identified the causes for the pneumonia in 705 of these patients.
Researchers found a low frequency (only 7.2%) of PES pathogens in immunocompetent patients with pneumonia, with 53 PES identified (P. aeruginosa, 34; ESBL-positive Enterobacteriaceae, 6; and MRSA, 13). Of note, however, the researchers detected several other drug-resistant pathogens than those considered as PES.
Patients positive for PES showed increased tendencies for initial treatment failure, followed by readmission to the hospital within 30 days, and also hospital longer stays.
To identify potential risk factors for PES, researchers analyzed multiple variables. They found that women and recent hospitalization periods (within 90 days) were two independent factors associated with infection with PES pathogens. Moreover, poorer overall health was also an independent risk factor, as well as enteral feeding (delivery of food directly into the stomach).
Based on the findings, researchers suggest that in immunocompetent patients with pneumonia, the definition of PES pathogens is actually an appropriate description of drug-resistant pathogens associated with this disease.
Despite the low frequency of PES detected in this patient cohort, researchers highlighted that the recognition of PES is vital since these pathogens can cause significant detrimental effects, “especially in patients with poor performance status or enteral feeding” the team wrote. Identifying PES in pneumonia patients is also important in choosing the appropriate antimicrobial treatments.