High diversity of genetic lineages and virulence genes in nasal <it>Staphylococcus aureus</it> isolates from donkeys destined to food consumption in Tunisia with predominance of the ruminant associated CC133 lineage

• Main Authors: Gharsa Haythem, Ben Sallem Rym, Ben Slama Karim, Gómez-Sanz Elena, Lozano Carmen, Jouini Ahlem, Klibi Naouel, Zarazaga Myriam, Boudabous Abdellatif, Torres Carmen
• Format: Article
• Language: English
• Published: BMC 2012-10-01
• Series: BMC Veterinary Research
• Subjects: <it>Staphylococcus aureus</it>; Donkey; <it>spa</it> types; CC133; Virulence genes; Tunisia
• Online Access: http://www.biomedcentral.com/1746-6148/8/203

<p>Abstract</p> <p>Background</p> <p>The objective of this study was to determine the genetic lineages and the incidence of antibiotic resistance and virulence determinants of nasal <it>Staphylococcus aureus</it> isolates of healthy donkeys destined to food consumption in Tunisia.</p> <p>Results</p> <p>Nasal swabs of 100 donkeys obtained in a large slaughterhouse in 2010 were inoculated in specific media for <it>S. aureus</it> and methicillin-resistant <it>S. aureus</it> (MRSA) recovery. <it>S. aureus</it> was obtained in 50% of the samples, being all of isolates methicillin-susceptible (MSSA). Genetic lineages, toxin gene profile, and antibiotic resistance mechanisms were determined in recovered isolates. Twenty-five different <it>spa</it>-types were detected among the 50 MSSA with 9 novel <it>spa</it>-types. <it>S. aureus</it> isolates were ascribed to <it>agr</it> type I (37 isolates), III (7), II (4), and IV (2). Sixteen different sequence-types (STs) were revealed by MLST, with seven new ones. STs belonging to clonal clomplex CC133 were majority. The gene <it>tst</it> was detected in 6 isolates and the gene <it>etb</it> in one isolate. Different combinations of enterotoxin, leukocidin and haemolysin genes were identified among <it>S. aureus</it> isolates. The <it>egc</it>-cluster-like and an incomplete <it>egc</it>-cluster-like were detected. Isolates resistant to penicillin, erythromycin, fusidic acid, streptomycin, ciprofloxacin, clindamycin, tetracycline, or chloramphenicol were found and the genes <it>bla</it>Z, <it>erm</it>(A), <it>erm</it>(C), <it>tet</it>(M), <it>fus</it>C were identified.</p> <p>Conclusions</p> <p>The nares of donkeys frequently harbor MSSA. They could be reservoirs of the ruminant-associated CC133 lineage and of toxin genes encoding TSST-1 and other virulence traits with potential implications in public health. CC133 seems to have a broader host distribution than expected.</p>