Polymicrobial Aggregates in Human Saliva Build the Oral Biofilm
Áurea Simón‐Soro, Zhi Ren, Bastiaan P. Krom, Michel A. Hoogenkamp, Pedro J. Cabello‐Yeves, Scott G. Daniel, Kyle Bittinger, Inmaculada Tomás, Hyun Koo, Álex Mira
Abstract
Microbes in biological fluids can be found as aggregates. How these multicellular structures bind to surfaces and initiate the biofilm life cycle remains understudied. Here, we investigate the structural organization of microbial aggregates in human saliva and their role in biofilm formation. We found diverse mixtures of aggregates with different sizes, structures, and compositions in addition to free-living cells. When individually tracked during binding and growth on tooth-like surfaces, most aggregates developed into structured biofilm communities, whereas most single cells remained static or were engulfed by the growing aggregates. Our results reveal that preformed microbial consortia adhere as "buds of growth," governing biofilm initiation without specific taxonomic order or cell-by-cell succession, which provide new insights into spatial and population heterogeneity development in complex ecosystems.