P3-05 Antibiotic Resistance of Different Staphylococcus aureus Strains Isolated from Clinical Samples and Artisanal Cheese Produced in Costa Rica

Wednesday, August 6, 2014
Exhibit Hall D (Indiana Convention Center)
Carolina Chaves, Universidad de Costa Rica, San Jose, Costa Rica
Introduction: In Costa Rica, there are few data regarding the antibiotic resistance profile of S. aureus strains isolated from cheese samples, and there is no evidence of similarity or difference from the profiles presented by clinical isolations.

Purpose: The aim of this work is to evaluate the occurrence of S. aureus in cheese samples, and compare the antibiotic resistance profile of these with some clinical isolates obtained from national hospitals.

Methods: S. aureus strains were isolated from 96 cheese samples produced in Costa Rica, using the methodology described by Pouch et al., 2011.  For the determination of the resistance profile of the isolated strains, the automatized Vitek system (BioMerieux) was used.  Also, 200 resistance profiles of clinical isolates were obtained from national hospitals.

Results: 172 S. aureus strains isolated from cheese samples and 218 clinical isolates were analyzed.  None presented resistance to vancomicine or linezolid.  Resistance levels were higher in the strains from clinical origin for all the antibiotics tested, except for tetracycline.  Both populations presented low resistance levels to trimethoprim sulfa and nitrofurantoine.

Significance: Some S. aureus strains present in cheese show resistance to different antibiotics and might eventually represent an important role in the dissemination of resistance genes between bacterial groups.