RESUMEN
PURPOSE: To examine the microbiologic spectrum of dacryocystitis, specifically characterizing differences between acute and chronic infection. METHODS: National multicenter prospective study of the microbiologic spectrum of acute and chronic dacryocystitis based on culture results reported between March 2005 and March 2006. Chi-square analysis was used to compare differences between groups. RESULTS: Eighty-nine patients from 16 centers were included: 21 (23.6%) patients had acute infection and 68 (76.4%) had chronic infection. Of all 89 patients, there were 80 total culture isolates with 55 (68.8%) Gram-positive isolates, 23 (28.7%) Gram-negative isolates, and 2 (2.5%) Mycobacterium isolates. In the acute group, 18/23 (78.3%) were Gram-positive and 5/23 (21.7%) were Gram-negative. In the chronic group, 37/57 (64.9%) were Gram-positive, 18/57 (31.6%) were Gram-negative, and 2/57 (3.5%) were Mycobacterium isolates. The proportions of Gram-positive and Gram-negative organisms between groups revealed no statistically significant difference (p > 0.20). The frequency of methicillin-resistant Staphylococcus aureus (MRSA) in the acute group, 4/23 (17.4%), was greater than the chronic group, 1/57 (1.8%) (p < or = 0.01). CONCLUSIONS: Gram-positive organisms were much more common than Gram-negative organisms overall, and the proportions did not differ significantly between the groups. Staphylococcus was the most common isolate in both groups, but there was a greater frequency of methicillin-resistant Staphylococcus aureus (MRSA) isolates in the acute group. The results of this study have important implications for the treatment of dacryocystitis.