Detection of Salmonellae in Captive and Free-Ranging Turtles Using Enrichment Culture and Polymerase Chain Reaction

Abstract

Information on the importance of captive turtles as sources of human Salmonella infections is well established; however, data on the potential of free-ranging turtles as carriers of salmonellae are scarce and contradictory. We combined traditional culture techniques and molecular tools to analyze swabs obtained from the cloacae and from different body parts of captive and free-ranging turtles for salmonellae. Salmonellae were detected in 50% of captive turtles (N = 10). A similar percentage of detection (51%) was obtained for salmonellae in free-ranging turtles from the Rio Grande (N = 80) with six sites at Big Bend National Park, Texas, and one site at Elephant Butte Reservoir, New Mexico, analyzed. Here, 46% of Trachemys gaigeae (N = 36), 56% of Apalone spinifera (N = 43), and the only individual of Chrysemys picta were positive for salmonellae. These percentages of detection of salmonellae in turtles were independent of the location of the sampling in the Rio Grande, the species and the gender of the turtles. Although individuals of captive turtles testing positive for salmonellae were generally positive for all body parts tested (i.e., the cloacae, the carapace, the ventral base of the left rear leg, underneath one or more of the claws on the front feet, and the ventral base of the tail), individuals of free-ranging turtles testing positive for salmonellae were often positive for only one or two body parts. Our results demonstrate that salmonellae are prevalent in high rates in both captive and free-ranging turtles.