Co-infection with influenza-associated acute respiratory distress syndrome requiring extracorporeal membrane oxygenation

The co-infection frequency and impact among influenza-associated acute respiratory distress syndrome (ARDS) patients requiring extracorporeal membrane oxygenation (ECMO) are not known. This retrospective observational analysis concerned data prospectively collected from patients admitted to our medical intensive care unit (ICU) who received ECMO support for influenza-associated ARDS between 2009-2016. Co-infection was defined as occurring within 48 h following ICU admission. Among the 77 ARDS patients requiring ECMO support, 39 (51%) developed co-infections, with Staphylococcus aureus [18 (46%) of the co-infected patients] being the most prevalent pathogen. Panton-Valentin leukocidin (PVL)-producing S. aureus was isolated from 10 patients (56% of S. aureus co-infections and 26% of all co-infections). Co-infected patients were comparable with those without co-infection, except for BMI, initial disease severity and antibiotic treatment prior to admission. Co-infection was associated with higher in-ICU mortality (62% vs. 29%; P = 0.006) and with fewer ECMO-free days [median (IQR) 0 (0-19) vs. 23 (0-46); P = 0.004] and fewer mechanical ventilation-free days [0 (0-0) vs. 6 (0-35); P = 0.003] on Day 60. Multivariable analysis retained age >49 years, pre-ECMO Simplified Acute Physiology Score (SAPS) II score >70 and co-infection as independent predictors of hospital mortality. In conclusion, co-infection is frequent in ECMO-treated patients with influenza-associated ARDS, affecting ca. 50%, and is independently associated with poor outcome. Staphylococcus aureus was the most frequently identified pathogen, with a high rate of PVL-positive S. aureus. Whether specific therapy targeting PVL-producing S. aureus should be given remains to be determined.