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. 2016 Jul:80:12-9.
doi: 10.1016/j.jcv.2016.04.008. Epub 2016 Apr 14.

Bacterial and viral co-infections complicating severe influenza: Incidence and impact among 507 U.S. patients, 2013-14

Nirav S Shah  1 , Jared A Greenberg  2 , Moira C McNulty  2 , Kevin S Gregg  3 , James Riddell 4th  3 , Julie E Mangino  4 , Devin M Weber  4 , Courtney L Hebert  5 , Natalie S Marzec  6 , Michelle A Barron  7 , Fredy Chaparro-Rojas  8 , Alejandro Restrepo  9 , Vagish Hemmige  9 , Kunatum Prasidthrathsint  10 , Sandra Cobb  10 , Loreen Herwaldt  10 , Vanessa Raabe  11 , Christopher R Cannavino  11 , Andrea Green Hines  12 , Sara H Bares  12 , Philip B Antiporta  13 , Tonya Scardina  14 , Ursula Patel  15 , Gail Reid  13 , Parvin Mohazabnia  16 , Suresh Kachhdiya  16 , Binh-Minh Le  16 , Connie J Park  17 , Belinda Ostrowsky  17 , Ari Robicsek  18 , Becky A Smith  19 , Jeanmarie Schied  20 , Micah M Bhatti  20 , Stockton Mayer  21 , Monica Sikka  21 , Ivette Murphy-Aguilu  21 , Priti Patwari  22 , Shira R Abeles  23 , Francesca J Torriani  23 , Zainab Abbas  24 , Sophie Toya  24 , Katherine Doktor  25 , Anindita Chakrabarti  25 , Susanne Doblecki-Lewis  25 , David J Looney  26 , Michael Z David  27
Affiliations

Bacterial and viral co-infections complicating severe influenza: Incidence and impact among 507 U.S. patients, 2013-14

Nirav S Shah et al. J Clin Virol. 2016 Jul.

Abstract

Background: Influenza acts synergistically with bacterial co-pathogens. Few studies have described co-infection in a large cohort with severe influenza infection.

Objectives: To describe the spectrum and clinical impact of co-infections.

Study design: Retrospective cohort study of patients with severe influenza infection from September 2013 through April 2014 in intensive care units at 33 U.S. hospitals comparing characteristics of cases with and without co-infection in bivariable and multivariable analysis.

Results: Of 507 adult and pediatric patients, 114 (22.5%) developed bacterial co-infection and 23 (4.5%) developed viral co-infection. Staphylococcus aureus was the most common cause of co-infection, isolated in 47 (9.3%) patients. Characteristics independently associated with the development of bacterial co-infection of adult patients in a logistic regression model included the absence of cardiovascular disease (OR 0.41 [0.23-0.73], p=0.003), leukocytosis (>11K/μl, OR 3.7 [2.2-6.2], p<0.001; reference: normal WBC 3.5-11K/μl) at ICU admission and a higher ICU admission SOFA score (for each increase by 1 in SOFA score, OR 1.1 [1.0-1.2], p=0.001). Bacterial co-infections (OR 2.2 [1.4-3.6], p=0.001) and viral co-infections (OR 3.1 [1.3-7.4], p=0.010) were both associated with death in bivariable analysis. Patients with a bacterial co-infection had a longer hospital stay, a longer ICU stay and were likely to have had a greater delay in the initiation of antiviral administration than patients without co-infection (p<0.05) in bivariable analysis.

Conclusions: Bacterial co-infections were common, resulted in delay of antiviral therapy and were associated with increased resource allocation and higher mortality.

Keywords: Co-infection; ICU; Influenza A (H1N1) pdm09; MRSA; Severe influenza; Staphylococcus aureus.

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Figures

Fig. 1
Fig. 1
Antibiogram of Staphylococcus aureus isolates (n = 47) from co-infections, showing the percent that were resistant or intermediate to selected antibacterial drugs from 47 patients with severe influenza in the U.S. between September 1, 2013 and April 1, 2014.
Fig. 2
Fig. 2
Percentage of community-acquired and hospital-acquired co-infections attributed to Staphylococcus aureus, Enterobacteriaceae and Pseudomonas sp. among 507 patients with severe influenza in the U.S. between September 1, 2013 and April 1, 2014.
See this image and copyright information in PMC

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