Species Interaction and Selective Carbon Addition During Antibiotic Exposure Enhances Bacterial Survival.

Biofilms are multifaceted and robust microbiological systems that enable microorganisms to withstand a multitude of environmental stresses and expand their habitat range. We have shown previously that nutritional status alters antibiotic susceptibility in a mixed-species biofilm. To further elucidate the effects of nutrient addition on inter-species dynamics and whole-biofilm susceptibility to high-dose streptomycin exposures, a CO Evolution Measurement System was used to monitor the metabolic activity of early steady state pure-culture and mixed-species biofilms containing and , with and without added carbon. Carbon supplementation was needed for biofilm recovery from high-dose streptomycin exposures when was either the dominant community member in a mixed-species biofilm (containing predominantly and ) or as a pure culture. By contrast, biofilms could recover from high-dose streptomycin exposures without the need for carbon addition during antibiotic exposure. Metagenomic analysis revealed that even when inocula were dominated by , the relative abundance of increased upon biofilm development to ultimately become the dominant species post-streptomycin exposure. The combined metabolic and metagenomic results demonstrated the relevance of inter-species influence on survival and that nutritional status has a strong influence on the survival of dominated biofilms.