Influenza-MRSA Co-Infection May Require Vancomycin Plus Second Antibiotic

According to data published in Clinical Infectious Diseases, the early addition of a second anti-methicillin-resistant Staphylococcus aureus (MRSA) antibiotic to vancomycin can reduce mortality in severe cases of influenza-MRSA co-infection in children.

Co-infection with influenza and MRSA may cause life-threatening necrotizing pneumonia in children and is associated with high fatality rates in critically ill children. Investigators prospectively enrolled 170 children younger than 18 with influenza infection and acute respiratory failure across 34 pediatric intensive care units from November 2008 to May 2016.

The study compared 3 conditions — MRSA co-infection, non-MRSA bacterial co-infection, and no bacterial co-infection — in terms of clinical course, therapy, and baseline characteristics.

Co-infection with influenza and MRSA was more frequently associated with leukopenia, acute lung injury, vasopressor use, extracorporeal life support, and mortality compared with both non-MRSA groups. Influenza-related mortality was 40% with MRSA and only 4.3% without (relative risk [RR], 9.3; 95% CI, 3.8-22.9).

Mortality in children with MRSA receiving vancomycin within 24 hours of hospitalization (n=29/30) dropped to 12.5% (n=2/16) when treatment included a second anti-MRSA antibiotic within the first 24 hours compared with 69.2% (n=9/13) with vancomycin monotherapy (RR, 5.5; 95% CI 1.4, 21.3; P =.003).

Children with severe comorbid conditions that predisposed them to influenza were excluded from the study, decreasing potential confounders but also generalizability. The study design was observational and the fact that the cohort of patients with MRSA was relatively small further limited the results. Investigators also noted that because MRSA co-infection can occur with other viruses and the study focused solely on influenza it cannot be determined whether the clinical course and outcomes of MRSA co-infection with other viruses are similar.

Despite these limitations, the study provides “real-world evidence” of the effectiveness of antibiotics in pediatric influenza-MRSA co-infections. Investigators further suggested that “a national ongoing registry of these fatal pediatric co-infections, with antimicrobial susceptibility, antibiotic management, and collection of clinical samples, could help guide care.”

Reference

Randolph A, Xu R, Novak T, et al. Vancomycin monotherapy may be insufficient to treat methicillin-resistant staphylococcus aureus coinfection in children with influenza-related critical illness [published online June 9 2018]. Clin Infect Dis. doi:10.1093/cid/ciy495