Microbiology and antibiotic management of orbital cellulitis.

Objectives: Orbital infections caused by methicillin-resistant Staphylococcus aureus may be increasing. Because Staphylococcus aureus infections have important treatment implications, our objective was to review the microbiology and antibiotic management of children hospitalized with orbital cellulitis and abscesses.
Patients and Methods: This study was a retrospective chart review of all patients admitted to a tertiary care children's hospital between 2004 and 2009 with orbital infections confirmed by a computed tomography scan. Patients with preceding surgery or trauma, anatomic eye abnormalities, malignancy, immunodeficiency, or preseptal infections were excluded.
Results: There were 94 children with orbital infections. A true pathogen was recovered in 31% of patients. The most commonly identified bacteria was the Streptococcus anginosus group (14 of 94 patients [15%]). Staphylococcus aureus (1 patient with methicillin-resistant Staphylococcus aureus) was identified in 9% of patients. Combination antimicrobial agents were frequently used (62%), and vancomycin use increased from 14% to 57% during the study period. Patients treated with a single antibiotic during hospitalization (n = 32), in contrast to combination therapy (n = 58), were more likely to be discharged on a single antibiotic (P < .001). Twenty-five (27%) patients were discharged on combination antibiotics. Thirteen (14%) patients were discharged on intravenous therapy.
Conclusions: The Streptococcus anginosus group is an emerging pathogen in pediatric orbital infections. Although methicillin-resistant Staphylococcus aureus was uncommon, patients frequently received vancomycin and combination antibiotics. A simplified antibiotic regimen may help limit the development of resistant organisms and facilitate transition to an oral agent.