Author: Marie Collison, Class of ‘25

A common adaptation of bacteria is antibiotic resistance, a very important field of study in microbiology and medicine. Antibiotic resistance genes (ARGs) can arise naturally and exist as an important natural survival tool for bacteria. ARGs have risen in frequency in human-inhabited regions as a result of increased use of antibiotics. As a result, there is growing concern over a possible future in which there is world-wide antibiotic resistance. Despite its seemingly inhospitable climate, Antarctica serves as a natural reservoir to a diverse and expansive group of complex microorganisms, making it an ideal location for microbiological studies. These microorganisms can cause snow to appear in various colors due to algae blooms, namely green (an initial stage of growth) and red (the phase after green snow). 

In a study published in January 2024, scientists Ze Ren, Huirong Li, and Wei Luo conducted metagenomic sequencing of red and green snow from the Fildes Peninsula in Antarctica to determine whether the distinct microbial communities also contained distinct ARG profiles. They discovered a total of 525 ARGs that spanned 30 classes of antibiotic resistance. Green snow contained more ARGs than red snow; it also contained more unique ARGs. Through the utilization of beta-diversity, the researchers determined that in the transition from green snow to red snow, ARGs experience increasingly stronger environmental sorting due to environmental changes. Multidrug resistance genes were the most diverse and prevalent version of ARGs. They also discovered ARGs correlating to resistance to beta-lactam, glycopeptide, fluoroquinolone, and peptide in high numbers in both snow types. They then created visual networks of the ARGs to compare them to the bacterial genera in which they were found. 

These findings emphasized the global prevalence of ARGs and indicate that the Antarctic Peninsula is home to a wide array of microbial antibiotic resistance genes. In addition, the categories of resistance offered by the isolated ARGs in this study give insight into crucial drivers that have shaped microbial resistance in various polar environments. Understanding the potential hosts of ARGs and the patterns that arise is a critical step in determining the ecological roles of antibiotic resistance. This is also an important step in understanding how hosts interact with ARGs to gain possible insight into mechanisms to prevent the widespread expansion of ARGs. 

Figure 1: “Watermelon snow” colored from micro-algae and cyanobacteria

[1] Ren, Z., Li, H., & Luo, W. (2024). Unraveling the mystery of antibiotic resistance genes in green and red Antarctic snow. Science of the Total Environment, 915. https://www.sciencedirect.com/science/article/pii/S0048969724002821

[2] Image retrieved from: http://www.flickr.com/photos/ifl/4896474273