Microbiological evaluation of corneal and contact lens cultures in contact lens-associated bacterial keratitis

To determine the degree of microbiological agreement between corneal scrapings and contact lens cultures in cases of contact lens-associated keratitis.Electronic medical records of all cases of contact lens-associated keratitis at a single institution from April 2006 to May 2019 were reviewed. Cases where both corneal scrapings and contact lens cultures were obtained were included in the study. Group 1 demonstrated agreement between corneal scrapings and contact lens cultures. Group 2 demonstrated growth on both cultures, but disagreement in isolated organism. Group 3 demonstrated negative corneal cultures but growth on contact lens cultures and the diagnostic yield of contact lens microbiological cultures and agreement between corneal and contact lens cultures.A total of 80 eyes of 72 patients were included in the study. 135 total incidences of microbiological results were included for data analysis. Group 1 contained nine incidences (6.7%), group 2 contained 60 incidences (44.4%) and group 3 contained 66 incidences (49%). In group 3, 50% of the cases were treated based on contact lens culture data. There was no statistically significant difference between all three groups in terms of baseline characteristics, presenting vision, vision at last follow-up, number of antibiotics used or complications from keratitis. Pseudomonas was the most common microorganism isolated, and in 89% of these cases, there was disagreement between corneal and contact lens cultures.Although there was a disagreement in the microbiological yield between contact lens and corneal cultures, contact lens cultures were useful in management of patients while achieving similar outcomes.