Bacteria have molecular sensors that evolved complex, interconnected pathways to sense and survive attacks to their cell wall by antibiotics. As antimicrobial infections across the U.S. increase, understanding the mechanisms bacteria use to sense and resist antibiotics is crucial to restoring the effectiveness of treatments. Bacteria have sigma factors that are activated when exposed to antibiotics, causing the cell to rebuild physical damage to the cell envelope. One mechanism used by Gram-positive bacteria is the csbB-yfhO operon, which provides defense against antibiotic-induced envelope stress, and its absence compromises viability. The operon contains promoters for SigX and SigB, sensors of envelope stress and physical stress, respectively. It is unclear how the upregulation of csbB-yfhO is controlled by these two sigma factors. One antibiotic that induces SigB is vancomycin; we hypothesize that csbB-yfhO could be upregulated during vancomycin stress through its SigB promoter. To test this, I will monitor csbB-yfhO expression levels through Reverse Transcription Quantitative PCR. I will use mutant strains lacking either sigB or sigX when exposed to vancomycin. We expect to see a drop in mRNA levels only when the SigB pathway is disrupted. Alternatively, SigX could be the primary inducer of the csbB-yfhO operon under vancomycin-induced stress. Ultimately, these findings will inform the broader biological community by revealing how bacteria survive antibiotic pressure, offering new targets to restore the effectiveness of existing treatments.