Characterization of Conjunctival Bacterial Flora of Healthy Laboratory-Housed New Zealand White Rabbits.

Abstract

OBJECTIVE: To characterize the conjunctival bacterial flora of laboratory-housed New Zealand White (NZW) rabbits using conventional culture techniques and quantitative bacterial analysis. ANIMALS STUDIED: This experimental study involved the collection of conjunctival fornix samples from 24 eyes of 12 healthy laboratory-housed NZW rabbits. PROCEDURES: Conjunctival samples were obtained using sterile dry swabs and processed using standard microbiological techniques. Bacterial identification was performed via mass spectrometry (MALDI-TOF), and quantification was expressed in colony-forming units per milliliter (CFU/mL). RESULTS: Bacterial growth was observed in 74% of the samples (17/24 eyes), with seven species identified: Moraxella cuniculi, Corynebacterium spp., coagulase-negative Staphylococcus, Bacillus spp., Staphylococcus aureus, Streptococcus viridans group, and Tsukamurella spp. Although most isolates were Gram-positive, M. cuniculi-a Gram-negative bacterium-was the predominant species. It exhibited the highest bacterial load (CFU/mL) and demonstrated a statistically significant difference compared to the other species (Kruskal-Wallis, p = 0.01). M. cuniculi also exhibited the highest variability in CFU/mL values among all isolates. CONCLUSIONS: Despite the predominance of Gram-positive isolates, M. cuniculi was identified as the predominant species in the conjunctival flora of healthy NZW rabbits, both in frequency and bacterial load. These findings contribute to a more detailed characterization of the ocular microbiota in this commonly used laboratory model.