Staphylococcal (including MRSA) and Streptococcal species are the most common pathogens in orbital cellulitis.
Orbital cellulitis typically occurs following rhinosinusitis though it can also be related to superficial skin injury, lacrimal system infections, hematogenous spread, styes and dental pathology.
Staphylococcal (including MRSA) and Streptococcal species are the most common pathogens currently though other organisms associated with rhinosinusitis and dental pathology are also seen. Streptococcus pneumoniae and Haemophilus influenzae type b are declining in prevalence due to immunization.
Hauser A, Fogarasi S. Periorbital and orbital cellulitis. Pediatr Rev. 2010 Jun;31(6):242-9. doi: 10.1542/pir.31-6-242. PMID: 20516236