Airborne Escherichia coli bacteria biosynthesize lipids in response to aerosolization stress.

Gram-negative bacteria pose an increased threat to public health because of their ability to evade the effects of many antimicrobials with growing antibiotic resistance globally. One key component of gram-negative bacteria resistance is the functionality and the cells' ability to repair the outer membrane (OM) which acts as a barrier for the cell to the external environment. The biosynthesis of lipids, particularly lipopolysaccharides, or lipooligosaccharides (LPS/LOS) is essential for OM repair. Here we show the phenotypic and genotypic changes of Escherichia coli MG1655 (E. coli) before and after exposure to short-term aerosolization, 5 min, and long-term indoor aerosolization, 30 min. Short-term aerosolization samples exhibited major damages to the OM and resulted in the elongation of the cells. Long-term aerosolization seemed to lead to cell lysis and aggregation of cell material. Disintegrated OM rendered some of the elongated cells susceptible to cytoplasmic leakage and other damages. Further analysis of the repairs the E. coli cells seemed to enact after short-term aerosolization revealed that the repair molecules were likely lipid-containing droplets that perfectly countered the air pressure impacting the E. coli cells. If lipid biosynthesis to counter the pressure is inhibited in bacteria that are exposed to environmental conditions with high air velocity, the cells would lyse or be exposed to more toxins and thus become more susceptible to antimicrobial treatments. This article is the first to show lipid behavior in response to aerosolization stress in airborne bacteria both genotypically and phenotypically. Understanding the relationship between environmental conditions in ventilated spaces, lipid biosynthesis, and cellular responses is crucial for developing effective strategies to combat bacterial infections and antibiotic resistance. By elucidating the repair mechanisms initiated by E. coli in response to aerosolization, this study contributes to the broader understanding of bacterial adaptation and vulnerability under specific environmental pressures. These insights may pave the way for novel therapeutic approaches that target lipid biosynthesis pathways and exploit vulnerabilities in bacterial defenses, ultimately improving treatment outcomes.