1344. Impact of Influenza A 2009 H1N1 (IA) on S. Aureus Nasal Colonization in Children
Session: Oral Abstract Session: Respiratory Infections in Children
Saturday, October 22, 2011: 2:45 PM
Room: 156ABC
Background: S. aureus (SA) is a leading cause of secondary pneumonia and death during influenza epidemics. During the pandemic of 2009-2010, 4 children in our hospital died with IA and community-acquired methicillin resistant S. aureus (CA-MRSA) co-infections. The present study was designed to assess the effect of influenza infection on SA colonization compared to other respiratory viruses. 

Methods: Anterior nares cultures were obtained from children hospitalized for respiratory viral infections diagnosed with a fluorescent antibody test on nasopharyngeal aspirates during the swine flu pandemic. SA isolates were characterized by pulsed field type (PT) and the presence of virulence genes including mecA, PVL, fnbA, fnbB, map/eap, sdrD, sdrE, v8, clfB, cna, tst and seg.  

Results: 104 children with influenza (IF), RSV, human metapneumovirus, parinfluenza virus, or adenovirus were enrolled. SA colonization was detected in 46% of IF infections (11/24), 17% of RSV (9/53) and 19% (5/27) of other viral infections, p = 0.02. Overall, 32% (8/25) SA isolates isolates were PT USA300 and 24% (6/25) were mecA positive. In contrast to the characteristics observed among the SA strains from our 4 fatal cases, no influenza infected child was colonized with a USA300, PVL positive isolate in the study.  SA from IF infected children more often possessed can, tst and seg genes,  and less often were PT USA300 or possessed mecA, PVL, fnbB, fnbB2, map/eap, sdrD, sdrE, and v8 genes, (various p values ≤0.05). However, children with influenza were significantly older than children with either RSV or other viral infections. We are currently analyzing age-controlled cohorts from the 2010-2011 influenza season in an attempt to see if factors other than age continue to be significant.

Conclusion: These data demonstrate differences in colonization rates of SA from influenza-infected children and different genotypic profiles of potential SA virulence factors compared to children infected with other viruses. The results suggest that the prevailing epidemic strain of influenza may modulate the colonizing capacity SA and select for strains with specific genotypic profiles.

Subject Category: P. Pediatric and perinatal infections

Howard Faden, MD, Univ at Buffalo/Women and Children's Hospital of Buffalo, Buffalo, NY, Kiran Majeed, MD, Women and Children's Hospital of Buffalo, Buffalo, NY and Alan Lesse, MD, Infectious Diseases, University at Buffalo/Buffalo VA Medical Center, Buffalo, NY


H. Faden, None

K. Majeed, None

A. Lesse, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.