Approximately half of children with complicated community-acquired pneumonia (cCAP) receive antibiotics for methicillin-resistant Staphylococcus aureus despite low positivity rates, based on data from a new study presented at the Pediatric Hospital Medicine (PHM) 2026 conference.

“The lack of data on complicated pneumonia etiology creates substantial uncertainty,” said Makenna Steger, MD, a third-year pediatric resident at Children’s Mercy Hospital in Kansas City, Missouri, and a coauthor on the study. “As residents, when we are caring for patients with this diagnosis who aren’t improving as expected or overnight when they have acute changes in their clinical status, we are frequently unsure about the need for MRSA coverage,” she said.

Pediatric complicated pneumonia is associated with substantial morbidity yet remains understudied; a primary gap is the precise epidemiologic and microbiologic description of its etiology, particularly regarding the characterization of S aureus and MRSA prevalence, said lead author Marina Dantas, MD, MSCR, a pediatric hospitalist at Children’s Mercy Hospital.

Generating patient-level data on specific causative pathogens and antibiotic selection is essential to confirming and reducing antibiotic overuse, she said.

The researchers conducted a chart review of children aged 60 days to 18 years hospitalized with cCAP from 2012 to 2022 at a single center, excluding those with immunodeficiency, congenital heart disease, chronic lung disease, cystic fibrosis, malignancy, or nonphysiologic airways. The study population included 129 patients with a median age of 5 years. The primary outcomes were pathogens identified on microbiological testing, antibiotic/pathogen concordance, and antibiotic regimen changes. Antibiotics were characterized as empiric (before diagnostic tests), postdiagnostic (following test results), and final (the last regimen). A total of 119 patients (92.3%) had pleural effusion or empyema, 117 of whom (90.7%) underwent drainage of pleural/abscess fluid.

Overall, Streptococcus pneumoniae was the most common pathogen (40 cases), followed by S aureus (10 cases), while MRSA accounted for 7 cases. However, 90% of patients received empiric antibiotics for MRSA, although 6% were concordant with microbiologic test results, 47% were discordant, and 47% were unknown. In addition, 48% of the patients received postdiagnostic MRSA antibiotics, and 67% received final MRSA antibiotics, although concordance was less than 15% in both groups. No increase in hospital readmission was noted among patients without MRSA antibiotics.

The frequent use of MRSA antibiotics was expected, but the extent exceeded the researchers’ expectations, as did the number of patients maintained on MRSA coverage despite the identification of an alternative pathogen, said Dantas.

“We expected to see high rates of empiric MRSA coverage but were surprised by how many patients continued to receive MRSA coverage after diagnostic testing was positive for a different bacterial pathogen,” said Berina Karisik, DO, also a third-year pediatric resident at Children’s Mercy Hospital and a study coauthor.

“Our hospital’s current clinical guidelines for complicated pneumonia recommend MRSA coverage in select cases or if there is severe illness; however, many patients receive MRSA coverage empirically simply because there is discomfort with the uncertainty of causative organism,” she said. “While it is uncomfortable to watch a patient clinically worsen, it doesn’t mean that their current antibiotic isn’t appropriately treating their infection, and the study findings highlight an area for improvement within our hospital for antibiotic stewardship,” she added.

Looking ahead, Dantas and colleagues are working to establish a research group to collect multicenter data from geographically diverse regions of the country to better define patterns of overuse and characterize the etiology of complicated pneumonia across communities and institutions.

“Developing and validating clinical prediction tools for pediatric MRSA-complicated pneumonia, similar to those long established in adult medicine, remains a critical priority,” Dantas said.

Raising Awareness to Inform Stewardship

“Limitations of this study include a small sample size with confirmed MRSA infections and the limited availability of microbiological data since in many cases the MRSA status of the patient was unknown,” said Shirin Mazumder, MD, an infectious diseases specialist and associate professor at the University of Tennessee Health Science Center, Memphis, who was not involved in the study. The study addressed a critical gap in optimizing antibiotic stewardship in pediatric care, she said.

“The lack of increased readmissions among those not receiving MRSA coverage may seem unexpected for some clinicians as there is often a concern that withholding broad-spectrum antibiotics can potentially lead to worse outcomes,” Mazumder noted. The results suggest that clinicians reconsider the routine use of empiric MRSA coverage in pediatric infections, particularly in patients without identifiable risk factors and in settings where the MRSA prevalence is low, she said. “A more targeted approach to empiric MRSA treatment may help to reduce unnecessary antibiotic exposure,” she added.

The study received no external funding. Senior author Jessica Markham, MD, MSc, received a career development K-award through the National Institutes of Health. 

Mazumder had no financial conflicts to disclose.