ABSTRACT
The breeding of meat rabbits is an important sector in the livestock industry in Italy. The focus of this study was to describe the antibiotic resistance profile distribution among the Methicillin-sensitive Staphylococcus aureus isolated in a rabbit farm. From 400 animals of different ages and three farm workers, 96 randomly selected strains isolated from various anatomical sites and lesions were analysed. According to spa typing and the resistance profiles towards veterinary and human antibiotics, 26 pathotypes were identified. The highest resistance was observed against Tetracyclines (92.3%) and Macrolides (80.8%), while almost all were susceptible to Penicillins, according to the limited use of ß-lactams on the farm. In total, 92.3% of pathotypes were multidrug resistant (MDRs). Two MDR pathotypes belonging to the t2802 spa type were isolated from both farmers and rabbits. Age categories harboured significantly different pathotypes (p = 0.019), while no association was found between pathotypes and lesions (p = 0.128) or sampling sites (p = 0.491). The antibiotic resistance was observed to increase with the time spent in the farm environment (age category). The selective pressure exerted by antibiotic use acted by giving advantage to more resistant strains rather than by lowering susceptibility to various drug categories within strains.
ABSTRACT
A study in an intensive Italian rabbit farm was carried out to assess the effect of age category and anatomical site on detection of S. aureus and to describe the diversity of spa-types within farm, including workers. On 400 rabbits of different age, 2066 samples from the ear, nose, axilla, groin, perineum and lesions were analyzed and 595 S. aureus were isolated. In total, 284 (71.0%) were colonized by S. aureus in at least one anatomical site and 35 animals (8.8%) had lesions. S. aureus prevalence was higher in adults than other age categories. Ear (29.4%) and nose (27.2%) were the most frequently colonized sites. The presence of lesions due to S. aureus was strongly associated with the colonization of at least one body site and the risk of lesions was proportionate to the number of sites colonized by S. aureus. In addition, a genotypic characterization was performed for 96 S. aureus strains randomly selected. All isolates resulted as low-virulence methicillin-sensitive-Staphylococcus aureus (LV-MSSA). Five different clonal lineages were found: spa-t2802, the most frequently detected (53.1%), also in human samples; spa-t491 (38.5%); spa-t094; t605; and spa-t2036. Strains t094, t491 and t2036 have not been isolated in Italy before.
