tetano
Editor, Senior Moderator
Infection
. 2026 Nov 9.
doi: 10.1007/s15010-026-03036-x. Online ahead of print.
Christoffer Vigen 1 , Bo Langhoff Hønge 2 , Jacob Redder 3 , Thomas Greve 4 , Lars Skov Dalgaard 5 , Anita Rath Sørensen 6 , Lotte Ebdrup 7 , Rajesh Mohey 8 , Britta Tarp 9 , Lars Østergaard 2 , Merete Storgaard 2 , Alexander Dutschke 4
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Purpose: To compare the prevalence, microbiological characteristics, and clinical impact of bacterial co-infection in adults hospitalized with respiratory syncytial virus (RSV) or influenza A infection.
Methods: We conducted a retrospective cohort study of adults hospitalized with laboratory-confirmed RSV or influenza A infection in Central Denmark. Bacterial co-infection was identified using bacterial culturing and urinary antigen testing. Poisson regression was used to estimate risk ratios for bacterial co-infection, and Cox proportional hazards regression was used to evaluate associations between bacterial co-infection and adverse clinical outcomes.
Results: Among 4,537 patients, 1,394 had RSV infection and 3,143 had influenza A infection. Among patients undergoing microbiological testing, bacterial co-infection was identified in 187/611 (30.6%) RSV-infected patients and 298/947 (31.5%) influenza A-infected patients (p = 0.72). Among all patients bacterial co-infection was identified in 187/1,394 (13.4%) RSV infected patients and 298/3,143 (9.5%) influenza A infected patients (p < 0.01) Haemophilus influenzae was the most common pathogen in both groups, followed by Streptococcus pneumoniae, Moraxella catarrhalis and Staphylococcus aureus. Bacterial co-infection was associated with increased ICU admission and mortality among influenza A infected patients, whereas estimates were lower in RSV.
Conclusions: Among patients undergoing microbiological testing, bacterial co-infection was identified at similar rates in patients hospitalized with RSV and influenza A infection. The most frequently isolated bacteria in both viral groups were bacterial species harboring genes for beta-lactamase production. These findings support consideration of tailoring the empirical antibiotic therapy to cover pathogens with beta-lactamase production when bacterial co-infection is suspected in RSV and influenza A infected patients. Bacterial co-infection was associated with poorer clinical outcomes in Influenza A than RSV.
Keywords: Bacterial co-infection; Influenza A virus; Mortality; Pneumonia; RSV; Respiratory syncytial virus.
. 2026 Nov 9.
doi: 10.1007/s15010-026-03036-x. Online ahead of print.
Bacterial co-infection in patients hospitalized with respiratory syncytial virus and influenza a infection: a retrospective observational cohort study
Christoffer Vigen 1 , Bo Langhoff Hønge 2 , Jacob Redder 3 , Thomas Greve 4 , Lars Skov Dalgaard 5 , Anita Rath Sørensen 6 , Lotte Ebdrup 7 , Rajesh Mohey 8 , Britta Tarp 9 , Lars Østergaard 2 , Merete Storgaard 2 , Alexander Dutschke 4
Affiliations Expand
- PMID: 43002358
- DOI: 10.1007/s15010-026-03036-x
Abstract
Purpose: To compare the prevalence, microbiological characteristics, and clinical impact of bacterial co-infection in adults hospitalized with respiratory syncytial virus (RSV) or influenza A infection.
Methods: We conducted a retrospective cohort study of adults hospitalized with laboratory-confirmed RSV or influenza A infection in Central Denmark. Bacterial co-infection was identified using bacterial culturing and urinary antigen testing. Poisson regression was used to estimate risk ratios for bacterial co-infection, and Cox proportional hazards regression was used to evaluate associations between bacterial co-infection and adverse clinical outcomes.
Results: Among 4,537 patients, 1,394 had RSV infection and 3,143 had influenza A infection. Among patients undergoing microbiological testing, bacterial co-infection was identified in 187/611 (30.6%) RSV-infected patients and 298/947 (31.5%) influenza A-infected patients (p = 0.72). Among all patients bacterial co-infection was identified in 187/1,394 (13.4%) RSV infected patients and 298/3,143 (9.5%) influenza A infected patients (p < 0.01) Haemophilus influenzae was the most common pathogen in both groups, followed by Streptococcus pneumoniae, Moraxella catarrhalis and Staphylococcus aureus. Bacterial co-infection was associated with increased ICU admission and mortality among influenza A infected patients, whereas estimates were lower in RSV.
Conclusions: Among patients undergoing microbiological testing, bacterial co-infection was identified at similar rates in patients hospitalized with RSV and influenza A infection. The most frequently isolated bacteria in both viral groups were bacterial species harboring genes for beta-lactamase production. These findings support consideration of tailoring the empirical antibiotic therapy to cover pathogens with beta-lactamase production when bacterial co-infection is suspected in RSV and influenza A infected patients. Bacterial co-infection was associated with poorer clinical outcomes in Influenza A than RSV.
Keywords: Bacterial co-infection; Influenza A virus; Mortality; Pneumonia; RSV; Respiratory syncytial virus.