Water and Flamingo Feces Bacterial Communities from High-Altitude Andean Lakes under Selective Antibiotic Pressure Studied by PCR-DGGE Analyses

Abstract

High-altitude Andean lakes are exposed to extreme environmental factors like high salinity, ultraviolet radiation, heavy metals, among others. As it was previously shown, these lakes are not only the habitat of a high diversity of bacteria with multiple resistances; they also support an enormous population of flamingos, which migrate among these wetlands, and they could play a role as disseminators and/or reservoirs of pathogenic bacteria.The aim of this work was to analyze, by Denaturant Gradient Gel Electrophoresis, the bacterial population under selective antibiotic pressure from bacterioplankton and flamingo feces from three lakes, placed between altitudes 4,200 and 4,560 m. Almost all bands were present in antibiotic-enriched cultures. Several bands identified in water were found in feces as well, presenting mainly correspondence with Gamma-proteobacteria. Few bands were exclusively identified in water, and those presenting correspondence with Alfa-proteobacteria and Actinobacteria were only identified in Laguna Azul.This study established that flamingos? enteric biota is in close interaction with lake water and demonstrated that bacteria with the ability to grow in antibiotics are abundant and diverse in the microbiota of Andean lakes. Additionally, flamingos could be considered as vectors of pathogenic organisms, since Stenotrophomonas seem to be the widest spread bacteria in the studied lakes.