OBJECTIVES

Infections have long been recognized as a major cause of ocular disease in animals. Patients with infectious eye diseases often require medical, surgical attention or both. Infectious agents cause or complicate a variety of ocular diseases in animals. The significance of infectious ocular diseases is not limited by certain microbial species. Virtually all vertebrates are susceptible to one (or more) of a variety of infectious agents that affect the eye. The aim of this study is to contribute to the knowledge of the normal saprophytic flora in Testudo graeca, by identifying the bacteria present on the conjunctiva of clinically healthy animals.

MATERIALS

Conjunctival swabs were taken from eyes of 10 long-term captive spur tighed tortoises from "El Valle" Wildlife Rehabilitation Center of Murcia (Spain). In the same way 6 free ranging tortoises from Sierra de Almenara (Murcia, Spain) were sampled. All 16 animals were clinically healthy; no symptomatology of Upper Respiratory Tract Disease (URTD) or signs of ocular disease were observed.

Swabs were placed in Amies transport medium and dispatched to the laboratory for bacteriological examination. The swabs were plated onto blood, McConkey and Hayflick agar plates during the course of the 24 hours following the sampling collection. The incubation was performed aerobically at 37°C. After 48 hours subcultures on blood agar were incubated in the same conditions as described above. Bacteria were identified to species using the API-20E, API-Staph and API-Coryne systems (Bio-Merieux, Barcelona, Spain). In certain instances where this systems were not sufficiently accurate to provide a definitive identification conventional biochemical tests were used.

RESULTS

Bacteria were recovered from 100 per cent of the specimens. Micrococcus luteus was the most common microorganism isolated (83,3%) in free ranging tortoises, Corynebacterium striatum, Pseudomonas fluorescens and Pseudomonas spp. were also isolated in 16,6% of the cases. Staphylococcus hominis was isolated and identified in one case, but we considered it as a human-origin contaminating bacteria.

In the case of long-term captive and clinically healthy tortoises, bacteria were recovered in 100% of the cases too. Staphylococcus xylosus was the most common microorganism isolated (90%), followed by Staphylococcus capitis (50%). Aeromonas hydrophila was also isolated in one case.

All Swabs were also cultured onto Hayflick media for Mycoplasma spp., but not growth was observed.

CONCLUSION

Micrococcus luteus was isolated from most of the samples of free ranging tortoises, so we can consider it as a saprophytic microorganism even though the small sample-size. Pseudomonas and Corynebacterium are considered as pathogenic bacteria, but no clinical signs were observed associated to them. This species should not be considered as normal saprophytic species until further studies confirm it.

Staphylococcus species isolated (xylosus and capitis) were the most common bacteria found in long-term captive tortoises, and were not associated with clinical ocular signs, although they have been reported as causative agents on mammalian diseases species of bovine mastitis and infections in cats. Aeromonas hydrophila has been described as an opportunistic agent, which normally affects immunosuppressed animals. It has been described as causative agent of disease in rattlesnake (Crotalus durissus) and amphibians, while in humans it is cause of gastroenteritis. The pathologic significance of this bacteria in tortoise's eyes is unknown.