Conjunctival bacterial flora in fellow eyes of patients less than 5 y/o with unilateral nasolacrimal obstruction and its changes after successful probing surgery

Background: Congenital nasolacrimal duct obstruction (CNLDO) is one of the leading causes of epiphora in infants, in which antibiotics are usually used as a conservative therapy in the first year. Objectives: This study aimed to evaluate the conjunctival bacterial flora in fellow eyes of patients 1-5 years old with unilateral NLDO and its changes after successful probing surgery. Methods: This prospective case-control study was conducted on children between 1-5 years old with unilateral NLDO with successful probing surgery in 2021. Before probing procedure and postoperative sampling from the conjunctiva of the eyes continued weekly until the colony count became negative or normal. Positive culture (clinically significant growths), colony count, and detected bacteria types reported. Results: The positive culture of conjunctival bacteria was observed in 71 (73.96%) in the case group and 35 eyes (36.46%) in the control group (P<0.0001). Most bacterial species in the case and control groups were gram-positive (75.61% and 82.86%, respectively; P=0.181). The most common isolated microorganisms in both groups were Staphylococcus epidermidis (54.95% and 51.43%) and Staphylococcus aureus (16.9% and 21.43%). The mean normalization time of bacterial culture was 1.92±0.54 weeks (between 1-3 weeks). The time for normalization of cultured bacteria was significantly related to the initial colony count≥1000 and the presence of a silicone tube (P<0.0001). Conclusions: Present study shows that gram-positive organisms with the predominance of Staphylococcus spp. were the significant conjunctival bacterial flora in pediatrics with NLDO. These findings could be helpful for management and appropriate antibiotic selection for treating of NLDO in our region.