Pediatric orbital cellulitis in the Haemophilus influenzae vaccine era

PURPOSE To evaluate the microbiology of pediatric orbital cellulitis in blood cultures and abscess drainage cultures following the introduction of the Haemophilus influenzae serotype b (Hib) vaccine. METHODS The medical records of all pediatrics patients (aged <18 years) at a tertiary pediatric hospital during the period January 2000 to July 2011 with a computed tomography orbital imaging querying "orbital cellulitis," "periorbital cellulitis," "preseptal cellulitis," or "postseptal cellulitis" were retrospectively reviewed. The records, Microbiology, and radiology of these patients were reviewed to assess the rates and complications of Haemophilus influenzae orbital cellulitis, including bacteremia and meningitis. RESULTS A total of 149 patients were diagnosed with preseptal or orbital cellulitis, of whom 101 (mean age, 7.2 +/- 4.0) had true orbital cellulitis. No patients grew Haemophilus influenzae from blood cultures. Of the 101 patients, 30 (29.7%) required surgical drainage and had abscess drainage fluid sent for microbiology. Of these, 18 (64.3%) had a positive culture: 4 (13.3%) grew Haemophilus influenzae from their abscess drainage fluid samples; 1 grew Haemophilus influenzae alone; and 3 had mixed growth that included Haemophilus influenzae. The patients positive for Haemophilus influenzae were significantly older and had significantly larger abscesses. CONCLUSIONS Although there were no cases of Haemophilus influenzae bacteremia or meningitis in our cases of orbital cellulitis, abscess drainage fluid microbiology indicated that Haemophilus influenzae remains a cause of orbital cellulitis. Haemophilus influenzae abscess volume was significantly larger than other bacterial abscesses and was associated with abscesses of mixed bacterial growth in older children.