Periorbital cellulitis seeded from

Periorbital cellulitis seeded from minor trauma to the skin is often caused by staphylococcal and streptococcal species, which account for greater than 70% of positive cultures (e.g., orbital/sinus，conjunctiva, blood) obtained from infected children (References 66-69, 71). Orbital cellulitis is often a complication of acute sinusitis (specifically the ethmoid sinus); thus, respiratory organisms such as Streptococcus pneumoniae, GAS, other streptococcal species (S. anginosus), S. aureus, nontypeable H.influenzae, or Moraxella catarrbalis are common pathogens. Although S.aureus is often implicated in these disease states, the pervasiveness of MRSA appears to be highly regional, ranging from 13% to 73% (References 65, 70). Mixed or polymicrobial infections, sometimes involving anaerobic organisms, tend to occur more commonly in older children because of the greater constriction between the sinus and their drainage passages, which impedes aeration and leads to an overgrowth of microbial flora