Abstract

VALLEJO, Marisol et al. Heavy metal resistance and virulence factors in Enterococcus strains isolated from the Chubut province, Argentina. Rev. Soc. Ven. Microbiol. [online]. 2016, vol.36, n.1, pp.16-22. ISSN 1315-2556.

Contamination by heavy metals is a growing problem for public health and the use of bio-indicators are means for assessing anthropogenic pollution. In this study 730 Enterococcus strains were isolated from different sources of the region VIRCh - Valdés (Province of Chubut) were tested for sensibility to Pb⁺⁺ by the plate dilution method at concentrations ranging from 50 mg/L to 1200 mg/L. A total of 223 strains displayed resistance to lead at concentration ≥ 50 mg/L. Among this group, and on the basis of its high resistance to lead (≥ 800 mg/L), 22 strains were selected with the goal to determine antibiotic and heavy metal resistance pattern and also the presence of virulence traits. All isolates showed high sensibility to Hg⁺⁺, a variable pattern against Cd⁺⁺ and Cr⁺⁶, and moderate resistance to Ni⁺⁺. The strains were all susceptible to ampicillin and penicillin and displayed a variable pattern of resistance towards the remaining antibiotics assayed. Among the virulence traits determined, gelatinase production was detected in 2 strains and only one isolate showed hemolytic activity. The results obtained in this work suggest a relationship between heavy metal resistance, antibiotic resistance and virulence factors in Enterococcus strains isolated from the environment.

Keywords : virulence factors; resistance to antibiotics; heavy metals; Enterococcus.

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