Reuse, Repurpose, and Recycle: Bacteriophages and Microbial Surveillance (1921-2023).

One of the historically most important yet overlooked forms of harnessing bacteriophages has been their use as bacterial diagnostics and as tools to type microbial environments. This article reconstructs the origins, global rise, and constant repurposing of bacteriophages for microbial surveillance. It shows the importance of phage-typing infrastructures for international networks of microbial exchange, which often favored the interests of high-income countries. It also analyzes phages' use as phenotypic diagnostics and their post-1980 repurposing within molecular and genomic platforms as well as phages' current revival as environmental surveillance tools in high- and low-income contexts. By connecting the phenotypic past and genomic present of phage diagnosis and typing, our analysis highlights the importance of bacteriophage reuse and technological recycling in driving innovation across basic and applied biomedical research. These findings challenge narrow molecular concepts of innovation and underline the need to pay critical attention to power asymmetries within existing microbial infrastructures.