Vancomycin susceptibility profiles of Staphylococcus spp. isolates from domestic and wild animals

Staphylococcus spp. are bacteria involved in human and animal infections. They are resistant to antimicrobials and have become a major public health concern. In recent years, there has been a significant increase in methicillin-resistant Staphylococcus strains and vancomycin is the drug of choice for the treatment of such isolates. However the minimum inhibitory concentration (MIC) of vancomycin necessary to combat this microorganism has been showing an increase. The aim of the present study was to determine the susceptibility profile of the Staphylococcus spp. of domestic and wild animals to vancomycin, using the microdilution in broth and E-test (R) techniques, as well as comparing the results of both tests. Of the 50 isolates tested, 47 (94 %) were sensitive to vancomycin in the microdilution and 43 (86 %) were sensitive to vancomycin in the E-test (R). Seven (14 %) isolates had an intermediate result showing a risk to public health since the detection of these isolates may precede the occurrence of'isolates resistant to vancomycin. In addition. the mec4 gene was detected in 78 % of the tested samples. Six of the seven isolates with intermediate resistance to vancomycin were carriers of the mec4 gene, showing that these isolates had a potential risk of becoming resistant. Thus, control measures must be taken to prevent the spread of these isolates with intermediate resistance and preserve the effectiveness of this antimicrobial for the treatment of infections caused by multiresistant Staphylococcus spp.