A total of 63 psychrotolerant bacteria exhibiting resistance to various antibiotics, such as ampicillin, streptomycin and/or trimethoprim, were isolated from diverse sites varying in terms of human influence, from obvious presence to probable absence, on Fildes Peninsula (King George Island, South Shetland Islands). The presence of class 1 integrons in some of these antibiotic resistant isolates was further determined. Plasmids from two isolates (HP19 and CN11) were transferred to Escherichia coli DH5α by conjugation. Sequence analysis of the plasmid from the HP19 isolate exhibited high similarity (~99%) to plasmid p34998-210.894kb of Enterobacter hormaechei subsp. steigerwaltii of clinical origin and confirmed the presence of a dfrA14 cassette in a class 1 integron context. 16S rRNA gene sequence analysis of five of these psychrotolerant isolates indicated similarity with environmental bacteria previously identified as Enterobacter species. Together, these results confirm that there may be no pristine niches for antibiotic resistance gene dissemination.
