To harvest the bacteria culture mentioned above, each plate was scraped using a sterile 20 μl pipette tip into a 1.5 ml Eppendorf tube filled with 1 ml of sterile 1x PBS. The tube was centrifuged at 800 xg for 10 mins, and the supernatant was discarded. The bacterial pellet was then incubated with 1 ml of Methacarn fixation solution (60% methanol, 30% chloroform, and 10% glacial acetic acid) for 30 mins at room temperature. During incubation, the tube was placed on a Mix Rack (ELMI, USA) and rotated at 10 rpm. After incubation, the bacteria were centrifuged at 800 xg for 10 mins, and the supernatant was discarded. The bacterial pellet was washed twice with 1 ml of PBS, each time centrifuging at 800 xg for 10 mins, and removing the supernatant. Subsequently, the bacteria were fixed with freshly prepared 4% PFA in 1x PBS for either 30 mins (for fluorescence / DSP imaging) or 6 hrs (for MIBI imaging). After fixation, the bacteria were washed twice with 1x PBS, each time centrifuging at 800 xg for 10 mins, and removing the supernatant. To facilitate embedding and storage, 20-50 μl of melted HistoGel (ThermoFisher, USA) was added to each bacterial sample. The sample was cooled at room temperature for 15 mins, followed by the addition of another 20-50 μl of melted HistoGel on top for sealing. The samples were then cooled at 4 °C for 1 hr until the HistoGel solidified. The solidified samples were removed from the Eppendorf tubes and placed in 9-compartment biopsy cassettes (EMS, USA). They were stored in 70% ethanol until processed in the pathology core at Stanford University, where they were embedded in paraffin blocks and sectioned into slides. Glass slides were used for fluorescence / DSP imaging, while gold slides (Ionpath, USA) were used for MIBI imaging. The slides were stored in vacuum chambers until they were ready for analysis. The fixation method used in this study, combining Methacarn and formalin fixation followed by paraffin embedding, was referred to as MFPE (Methacarn and Formalin-fixed, Paraffin-Embedded). This method enabled the preservation of mucus structure and protein epitopes.