Coinfection with Staphylococcus aureus increases risk of severe coagulopathy in critically ill children with influenza A (H1N1) virus infection.

OBJECTIVES

H1N1 influenza with coinfections has been implicated to have high morbidity and mortality. We hypothesized that critically ill children with 2009 H1N1 and coinfections are at a higher risk of developing disseminated intravascular coagulation.

DESIGN

The chart review included demographics, length-of-stay, severity of illness score (Pediatric Risk of Mortality III acute physiology score), clinical laboratories, and outcomes at hospital day 90 data. Patients were classified as having methicillin-sensitive or -resistant Staphylococcus aureus, other, or no coinfections.

SETTING

Single-center pediatric intensive care unit.

PATIENTS

Sixty-six consecutive patients with 2009 H1N1 and influenza A infection.

INTERVENTIONS

None.

MAIN RESULTS

: There were 12, 22, and 32 patients with methicillin-sensitive or -resistant Staphylococcus aureus, other, and no coinfections, respectively. Pediatric critical care unit length-of-stay was 11, 10, and 5.5 days (median), and survival at day 90 was 83%, 96%, and 91% in patients with methicillin-sensitive or -resistant Staphylococcus aureus, other, and no coinfections. Patients with methicillin-sensitive or -resistant Staphylococcus aureus coinfections compared to patients with other, and no coinfections had higher Pediatric Risk of Mortality III acute physiology scores (14 [6-25] vs. 7 [2-10], p = .052 and 6 [2.5-10], p = .008; median [interquartile range]), higher D-dimer (16.1 [7.9-19.3] vs. 1.6 [1.1-4], p = .02 and 2.3 [0.8-8.7] µg/mL, p = .05), longer prothrombin time (19.3 [15.4-25.9] vs. 15.3 [14.8-17.1], p = .04 and 16.6 [14.7-20.4] secs, p < .39) at admission, and lower day-7 platelet counts (90K [26-161K] vs. 277K [98-314], p = .03 and 256K [152-339]/mm, p < .07). Patients with methicillin-sensitive or -resistant Staphylococcus aureus coinfections compared to patients without coinfections were more likely to be sicker with Pediatric Risk of Mortality III acute physiology score >10 vs. <10 (relative risk 2.4; 95% confidence interval 1.2-4.7; p = .035) and have overt disseminated intravascular coagulation (relative risk 4.4; 95% confidence interval 1.3-15.8, p = .025).

CONCLUSIONS

During the 2009-2010 H1N1 pandemic, pediatric patients with influenza A and methicillin-sensitive or -resistant Staphylococcus aureus coinfections were sicker and more likely to develop disseminated intravascular coagulation than patients with other or no coinfections.