Bacterial Recovery from Canine Eyes with Complicated Corneal Ulcerations: Comparison of Direct Plating Versus Culturette Submission: A Pilot Study
Haley E Jost1, Christine C Lim2, Leslie Sharkey3, Julia L Sharp4, Michael L Creutzinger4 and Michala de Linde Henriksen1*
1Comparative Ophthalmology, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, USA
2Eye Care for Animals, USA
3Clinical Sciences Department, Cummings School of Veterinary Medicine, Tufts University, USA
4Department of Statistics, College of Natural Sciences, Colorado State University, USA
*Corresponding Author: Michala de Linde Henriksen, Comparative Ophthalmology, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, USA.
January 27, 2022; Published: February 11, 2022
Objective: To compare organism recovery from canine corneal ulcers using two different bacterial culture processing methods: culturette inoculation into growth media immediately after collection (direct plating), and transport of culturettes with inoculation at the reference laboratory (culturette).
Design: Exploratory pilot study.
Animals: Thirteen client-owned dogs diagnosed with complicated corneal ulceration from one referral hospital.
Procedures: Bacterial samples were collected by direct sampling of infected corneal ulcerations with a culturette followed by two methods of sample processing: 1) direct inoculation of the culturette onto four culture media (blood, MacConkey, chocolate, Sabouraud dextrose) and shipment of plates to an outside laboratory, 2) sample collection by culturette followed by transport to the same outside laboratory for plating there for aerobic bacterial culture and sensitivity testing. Corneal cytology was collected from all corneal ulcerations immediately after culture samples were obtained.
Results: Direct plating detected bacterial infection in 5/13 (39%) dogs, culturette submission in 6/13 (46%) dogs. When combining the two culture methods, 7/13 (54%) dogs had positive cultures. The most common bacteria that were cultured from the corneal ulcerations were beta-hemolytic streptococcus spp. (n = 3), and gram-negative bacilli (n = 3). There was not sufficient evidence to suggest bacterial detection differed between the two culture methods (p = 1.00).
Conclusions and Clinical Relevance: Some laboratories recommend direct plating for better bacterial growth from corneal cultures. Direct plating is more time consuming than submitting a culturette. This study suggests that submitting a culturette does not result in different bacterial growth than direct plating.
Keywords: Canine; Culturette; Direct Plating; Infected Corneal Ulceration; Microbiology
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