Antibiotic resistance among bacteria isolated from seawater and penguin fecal samples collected near Palmer Station, AntarcticaThis article is one of a selection of papers in the Special Issue on Polar and Alpine Microbiology.

Abstract

Antibiotic resistance in aquatic bacteria has increased steadily as a consequence of the widespread use of antibiotics, but practice and international treaty should have limited antibiotic contamination in Antarctica. We estimated antibiotic resistance in microorganisms isolated from the Antarctic marine waters and a penguin rookery, for 2 reasons: (i) as a measure of human impact and (ii) as a potential "snapshot" of the preantibiotic world. Samples were taken at 4 established sampling sites near Palmer Station, which is situated at the southern end of the Palmer Archipelago (64 degrees 10'S, 61 degrees 50'W). Sites were chosen to provide different potentials for human contamination. Forty 50 mL samples of seawater were collected and colony-forming units (CFU)/mL were determined at 6 and 20 degrees C. For this study, presumed psychrophiles (growth at 6 degrees C) were assumed to be native to Antarctic waters, whereas presumed mesophiles (growth at 20 degrees C but not at 6 degrees C) were taken to represent introduced organisms. The 20-6 degrees C CFU/mL ratio was used as a measure of the relative impact to the ecosystem of presumably introduced organisms. This ratio was highest at the site nearest to Palmer Station and decreased with distance from it, suggesting that human presence has impacted the natural microbial flora of the site. The frequency of resistance to 5 common antibiotics was determined in each group of isolates. Overall drug resistance was higher among the presumed mesophiles than the presumed psychrophiles and increased with proximity to Palmer Station, with the presumed mesophiles showing higher frequencies of single and multiple drug resistance than the psychrophile population. The frequency of multidrug resistance followed the same pattern. It appears that multidrug resistance is low among native Antarctic bacteria but is increased by human habitation.

Respiratory Microbiome of Endangered Southern Resident Killer Whales and Microbiota of Surrounding Sea Surface Microlayer in the Eastern North Pacific

“…A correlation may exist between the lack of secondary treatment for sewage entering the Salish Sea and the presence of antibiotic resistant bacteria within SRKW breath and SML samples. Support for this association comes from prior studies demonstrating that antibiotic resistant bacteria present in seawater isolates increase in frequency in areas of human habitation without secondary sewage treatment facilities 39 .…”

Antimicrobial activity and resistance to heavy metals and antibiotics of heterotrophic bacteria isolated from sediment and soil samples collected from two Antarctic islands

“…Antibiotic resistance genes are often located on plasmids that are able to transfer horizontally among diverse bacterial populations, thus contributing to the widespread dissemination of antibiotic resistance in the environment (Davison 1999;Herreros et al 2005). Antibiotic resistance has also been reported among bacteria in cold environments such as Antarctic sandstone in McMurdo Valley (Siebert et al 1996), the Arctic permafrost subsoil in Siberia (Mindlin et al 2008), Antarctic King George Island (Wong et al 2011), and seawater and penguin faecal samples collected near Palmer Station, Antarctica (Miller et al 2009). A high frequency of bacteria resistant to antibiotics can be viewed as an indicator of environmental pollution (Zhang et al 2009).…”

“…A high frequency of bacteria resistant to antibiotics can be viewed as an indicator of environmental pollution (Zhang et al 2009). Isolation of antibiotic-resistant bacteria from areas with limited human activity can be a good indicator of human impact on these natural areas, such as the Antarctic region (Miller et al 2009). The relatively high percentage of multidrugresistant bacteria determined in this study (79%) may suggest medium anthropogenic impact in these Antarctic regions.…”

“…Thus, in an environment with multiple stresses, for example antibiotics and heavy metals, it would be more beneficial to the survival of bacteria to acquire resistance to both stresses. It has been reported that bacterial plasmids are ubiquitous, including natural microbial assemblages of the marine ecosystem of Antarctica (Kobori et al 1984;De Souza et al 2006;Miller et al 2009;Mangano et al 2011). Plasmid DNA was detected in 25% of A1 strains and in 17% of A2 strains.…”

Antimicrobial resistance in wildlife

“…). Studies highlighted the presence of AMR in all ecosystems including the most isolated ones such as Antarctica (Miller, Gammon & Day ) and in a wide range of species (Allen et al . ).…”