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 H. 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 H. 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 H. influenzae from their abscess drainage fluid samples; 1 grew H. influenzae alone; and 3 had mixed growth that included H. influenzae . The patients positive for H. influenzae were significantly older and had significantly larger abscesses. Conclusions Although there were no cases of H. influenzae bacteremia or meningitis in our cases of orbital cellulitis, abscess drainage fluid microbiology indicated that H. influenzae remains a cause of orbital cellulitis. H. influenzae abscess volume was significantly larger than other bacterial abscesses and was associated with abscesses of mixed bacterial growth in older children.