CONJUNCTIVAL MICROFLORA IN GUINEA PIGS WITH AND WITHOUT SIGNS OF CONJUNCTIVITIS

Abstract

This study was performed to compare the conjunctival microflora in clinically healthy guinea pigs and guinea pigs exhibiting clinical signs of conjunctivitis. Twenty guinea pigs (40 eyes) with similar age (12 to 20 months) were used for this study. Slit-lamp examination was performed and 11 guinea pigs were diagnosed with conjunctivitis and the presence of ocular discharge and hyperemia. Conjunctival swabs were taken from both eyes of 9 healthy guinea pigs and 11 guinea pigs with conjunctivitis. For all isolates, the susceptibility to commonly used antimicrobials was determined by means of the Kirby-Bauer method. Sixteen eyes (72%) showed bacterial growth in guinea pigs with conjunctivitis and 14 eyes (77%) indicated bacterial growth in clinically normal guinea pigs. Staphylococcus spp. (4/22; 18.1%) and Moraxella spp. (4/22; 18.1%) were respectively the most commonly isolated organisms in guinea pigs with signs of conjunctivitis. In clinically healthy guinea pigs, the most commonly isolated bacterial organisms were Staphylococcus spp. (8/18; 44.4%) and Bacillus spp. (4/18; 22.2%), respectively. Most isolated bacteria were sensitive to common antibiotics. There were 2 exceptions in guinea pigs with conjunctivitis: Moraxella spp. was resistant to vancomycin and ampicillin, while Staphylococcus aureus was resistant to erythromycin. Results revealed the dominance of Gram-positive bacteria in the conjunctiva of guinea pigs with signs of conjunctivitis with the presence of Moraxella spp., Clostridium spp., and Listeria spp.