Citrobacter freundii-associated lesions in stranded loggerhead sea turtles (Caretta caretta)

Citrobacter freundii, an opportunistic bacterial pathogen belonging to the family Enterobacteriaceae, has been sporadically reported in sea turtles. Here, the authors describe 3 unusual lesions associated with C. freundii infection in 3 loggerhead sea turtles stranded on the coast of Gran Canaria Island, Spain. It is possible that these 3 distinct lesions played a major role in the death of these turtles. The first turtle had caseous cholecystitis, a lesion not previously described in sea turtles. The second turtle had large intestinal diverticulitis, a rare condition in loggerheads. The third turtle had bilateral caseous salt gland adenitis. Histologically, numerous gram-negative bacilli were observed at the deepest edge of inflammation in all cases. Pure cultures of C. freundii were obtained from these 3 lesions. Molecular detection of C. freundii DNA in formalin-fixed paraffin-embedded samples from the lesions of the 3 turtles confirmed the microbiological isolation. These cases, in addition to expanding the limited body of knowledge on bacterial infections in sea turtles, highlight the potential pathogenic role of C. freundii in loggerhead turtles.