Faecal enterococci from camels in Tunisia: species, antibiotic resistance and virulent genes

Abstract

Enterococci species are commensal microorganisms found in the gastrointestinal tract of animals and humans, being commonly isolated from faeces, water, plants, soil and food products, among others (Aarestrup and others 2000, Mannu and others 2003, Abriouel and others 2008). Enterococci are also important human pathogens being frequently implicated in human infections. These microorganisms present a high capacity of acquisition of antibiotic resistance mechanisms through horizontal gene transfer (Hammerum and others 2010). Of special relevance is the acquisition by enterococci of vancomycin-resistant genes, and the emergence of these resistant isolates in animals is being associated to the use of avoparcin in the past as an animal growth-promoter in some countries (Hammerum and others 2010). It is important to characterise the resistance and virulence trait characteristics of enterococci borne in different animals that could come in contact with human beings, and also to identify the species and clones circulating within animal ecosystems. Toward these aims, this study has been focused in order to study antibiotic resistance and presence of virulent genes in enterococci recovered from faecal samples of camels in Tunisia, and to determine the genetic diversity among the predominant species detected by pulsed-field gel electrophoresis (PFGE). To our knowledge, this is the first study that analyses the diversity and the characteristics of faecal enterococci in camels. Faecal samples of 100 camels (one sample per animal) from different regions of Tunisia (north, centre and south) were collected in this study. Samples were diluted and seeded in Slanetz-Bartley agar plates and they were incubated for 48 hours at 37°C. Phenotypic identification at the genus level of recovered isolates was based on Gram stain, bile-aesculin and hypersalin tests. Identification of Enterococcus species …