Abstract

Monitoring antibiotic resistance in wildlife from remote areas can be a valuable tool for evaluating the impact of human pressure. We investigated the effect of contamination with arsenic (As), lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) on bacterial populations isolated from excreta of the Humboldt penguin (Spheniscus humboldti). Bacterial communities were studied at three important nesting places of the Humboldt penguin on the Chilean coast of Chile: Pan de Azúcar Island, Chañaral Island, and Cachagua Island. Bacteria resistance patterns to heavy metals and antibiotics were evaluated. There were differences in heavy metal-resistant bacteria between colonies of penguins. All bacterial strains isolated from penguin droppings in all three locations showed resistance to Zn. Bacterial strains isolated from feces in Cachagua Island exhibited the highest resistance to As, Cu and Pb, being this location that which exhibited the highest concentrations for these metals. Samples from Cachagua Island indicated that Enterococcus durans, E. faecium, Pseudomonas spp. and Brevundimonas vesicularis were resistant to Cd. The most toxic metal was Cd, followed by Cu. All gram (+) bacteria showed resistance to cefapirin, oxytetracycline, florfenicol, amoxicillin, gentamicin, penicillin, and sulfatrimet, whereas gram (-) bacteria were resistant to penicillin and sulfatrimet. Metal-resistant strains could affect the organic and inorganic cycles at places where Humboldt penguin lives.