Characterization of Culturable Bacterial Communities in Permafrost, Moraine, and Rhizosphere Soils near the Ecology Glacier (King George Island, Maritime Antarctica): Patterns of Antibiotic Resistance and Virulence Factors in Isolated Bacteria

Glacier forelands in the Antarctic Peninsula are increasingly affected by climate change. However, the impact on the composition of culturable soil bacteria communities remains unclear. Here, we explored the culturable bacterial communities from permafrost (P), moraine (M), and Deschampsia antartica rhizosphere (R) soil samples collected near the Ecology Glacier, Antarctica. Using traditional plating-on agar (PM) and ' in situ ' cultivation (ISC) methods, bacterial counts were significantly higher in R (8.2×10 ⁵ CFU g ^− 1 soil) than in M and P (~ 3.9 ×10 ³ CFU g ^− 1 soil). Culturable lawn bacteria communities and 158 genotypically different isolated strains (76 by ISC and 82 by PM) were identified, purified. And their antibiotics multiresistance (AMR) and virulence factors (VFs) were also screened. Our results revealed phyla Pseudomonadota (55–75%), Actinomicetota (20–35%), and Bacteroidota (5–10%) as the most abundant bacterial taxa in culturable bacteria lawn communities. The isolated strains belonged to 24 different bacteria genera, where Pseudomonadota (76%), Actinomicetota (18%), Bacteroidota (4.6%), and Bacillota (3.2%) were the most dominant phyla. Using ISC, a wider genera diversity (e.g., Bosea , Rathayibacter , and Rugamonas ) was isolated. On the other hand, Bacillus exclusively grew on PM. Among these isolates, 86% were resistant to beta-lactams, 77% to cephalosporins, and 71% to oxazolidines. Interestingly, some Flavobacterium , Pseudomonas , and Curtobacterium strains showed AMR to > 18 different antibiotics. For VFs assays, we also observed > 35% lecithinase and hemolytic activity, 20% pyocyanin production, and 7% DNAse activity among all isolates. A high diversity of AMR and VFs was observed in culturable bacteria inhabiting the surrounding soils of the Ecology Glacier.