Serotypes and antibiotic susceptibility patterns of Salmonella spp. isolates from spur-thighed tortoise, Testudo graeca illegally introduced in Italy

Abstract. The prevalence of Salmonella carriage and distribution of serotypes in spur-thighed tortoises, Testudo graeca Linnaeus, 1758 illegally introduced in Italy was studied to assess the risk of disease exposure for humans once these specimens were traded as pets. Antibiotic susceptibility patterns were also analyzed to estimate the emergence of antibiotic-resistant Salmonella strains. One hundred forty-six cloacal swabs of spur-thighed tortoises were tested by standard bacteriological methods. Antimicrobial susceptibility tests on Salmonella strains isolated were also performed. Ninety-one Salmonella spp. strains were isolated in 74 of 146 turtles examined and a total of 20 different serotypes were found. Out of the 91 isolates, 67 were grouped in the Salmonella enterica subspecies I. Salmonella isolates were susceptible to most of the antibiotics tested. Resistance was most commonly observed against tetracycline (57.1%) followed by ampicillin (33.0%), streptomycin (13.2%) and amoxicillin-clavulanic acid (11.0%). Our findings confirm that wild-caught spur-thighed tortoises can carry different serotypes of Salmonella. Accordingly, strict preventive sanitation measures should be adopted when handling reptiles.