Large TP, Mack S, Villiers E, Oliver J. In vitro susceptibility of canine corneal bacterial pathogens to three cross-linking protocols.
Vet Ophthalmol 2022;
26 Suppl 1:134-142. [PMID:
35713165 DOI:
10.1111/vop.13006]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVE
To assess in vitro antibacterial efficacy of three cross-linking (XL) protocols on bacteria associated with canine ulcerative keratitis.
METHODS
Three XL protocols: UVA 3 mW/cm2 for 60 min, UVA 3 mW/cm2 for 30 min, and UVA 30 mW/cm2 for 3 min with and without application of riboflavin and a riboflavin-only protocol were performed in vitro on the four most common bacterial genera isolated from cases of canine ulcerative keratitis treated at Dick White Referrals, UK. Zones of bacterial growth inhibition (GIZ) associated with treatment were measured and compared.
RESULTS
The four most common isolates were Pseudomonas aeruginosa (PA) (48/140, 34.3%), Streptococcus spp. (32/140, 22.9%), Staphylococcus spp. (24/140, 17.1%) and Escherichia coli (EC) (11/140, 7.9%). PA, EC, Streptococcus canis (SC), and Staphylococcus pseudintermedius (SP), isolated from canine corneas, were selected for testing. EC and SC demonstrated growth inhibition following all UVA/riboflavin protocols. PA and SP only displayed growth inhibition following the 60 min UVA/riboflavin protocol. GIZ areas for 60 min UVA/riboflavin protocols were significantly greater than 30 and 3 min UVA/riboflavin protocols (p < .01) and there was no significant difference between 30 and 3 min UVA/riboflavin protocols. In respect to GIZ areas, EC was significantly more susceptible to XL than SP (p = <.01).
CONCLUSIONS
All UVA/riboflavin XL protocols caused growth inhibition of EC and SC in vitro. PA and SP did not show clear growth inhibition in vitro following exposure to XL protocol settings of UVA 3 mW/cm2 for 30 min and UVA 30 mW/cm2 for 3 min.
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