Comparison of corneal culture results obtained using the ESwab (TM) and Amies charcoal swab in canine and feline patients

Objective: The objective of the study was to compare corneal culture results using the ESwab (TM) and Amies charcoal swab. Animals studied: One hundred fourteen canine and fifteen feline eyes. Procedures: Retrospective analysis of Dick White Referrals bacterial and fungal corneal culture data was conducted. Results were included from canine and feline patients, which presented with suspected infectious keratitis that had samples taken using an Amies charcoal swab followed by an ESwab (TM) in the same eye. In respect to positive and negative cultures, a McNemar test was conducted comparing instances of disagreement between swab types, and the Kappa coefficient (kappa) was calculated to assess the level of agreement between swab types. Results: The ESwab (TM) produced more positive corneal cultures (71/129 [55.0%]) than the Amies charcoal swab (41/129 [31.8%]). 2/129 eyes produced positive fungal cultures. Considering 37/129 eyes in which both swab types detected a positive corneal culture, the same bacterial species were cultured from each swab type in 34/37 (91.9%) eyes, and an additional bacterial species was cultured by the ESwah (TM) in 3/37 (8.1%) eyes. In 34/38 (89.5%), instances of disagreement between swab types, the ESwab (TM) showed a positive culture, and the Amies charcoal swab showed a negative culture from the same eye, and this difference was significant (p < 0.0001). There was a moderate level of agreement between results from both swab types (kappa = 0.432). Conclusions: ESwab (TM) sampling alone may be superior to Amies charcoal swabs for detecting presence of bacteria in suspected infectious keratitis in cats and dogs.