BACTERIAL MICROFLORA ISOLATED FROM GASTROINTESTINAL TRACT
OF LOGGERHEAD SEA TURTLES (Caretta caretta) AND THEIR ANTIBIOTIC
RESISTANCE
Elena Zinaić¹, Danijela Horvatek Tomic2, Karin Gobić3, Maja Lukač2
¹Faculty of Veterinary Medicine University of Zagreb
²Department of Poultry Diseases with Clinic, Faculty of Veterinary Medicine, University of
Zagreb
3
Marine Educational Centre Pula, Croatia
The information on normal gastrointestinal bacterial flora and antibiotic resistance in
loggerhead sea turtles (Caretta caretta) is very scarce. The aim of this study was to get the
better insight of its composition.
For that purpose, oral cavity and cloacal swabs were taken from 17 animals situated at
Marine rescue centre Pula. All the samples were plated on nutrient and brilliant green agars
and incubated 24 hours at room temperature. After the incubation, all grown bacteria were
further identified according to their morphology, Gram staining, catalase and oxidase tests
and also by API commercial strips. Antimicrobial resistance was determined by disk diffusion
method.
From oral cavity, 13 different bacterial species were isolated, 9 gram negative and 4
gram positive. Most common bacteria from oral cavity were Schewanella putrefaciens,
followed by Escherichia coli and Micrococcus luteus. From cloaca 15 different bacteria were
isolated, 12 gram negative and 3 gram positive species. Most common bacteria isolated from
cloaca were Escherichia coli, Proteus vulgaris and Schewanella putrefaciens, followed by
Aeromonas salmonicida and Micrococcus sp.. All the other isolated bacteria such as
Citrobacter braaki, Citrobacter freundi and, Pseudomonas fluorescens were only randomly
isolated from cloaca.
All identified bacteria were resistant to amoxicilin, amoxicilin clavulanate and
lincomicin. Seven other tested antibiotics have shown a wide range of sensitivity.
Most of the isolated bacteria belongs to ubiquitous microorganisms specific for marine
environment. However, some of these bacteria were also described as pathogenic for
immunocompromised animals and humans.
This results can be of interest in the treatment of injured and stressed animals in rescue
centers and for the people in closer contact with those animals during their rehabilitation.
Most of isolated gram negative bacteria are considered to be opportunistic pathogens as they
can cause clinical diseases in immunocompromised animals, but also in humans.