Phenotypic Resistance in Photodynamic Inactivation Unravelled at the Single Bacterium Level

• DOI: 10.1021/acsinfecdis.9b00185
• Publication Date: 2019-07-09T12:19:47Z
• Authors: Sol R. Martínez; Yohana B. Palacios; Daniel A. Heredia; Maximiliano L. Ag...; Andrés M. Durantini
• Keywords: Methicillin-Resistant Staphylococcus aureus; 0303 health sciences; Microbial Viability; Photosensitizing Agents; Molecular Structure; SINGLE CELL; PHOTODYNAMIC INACTIVATION; FLUORESCENCE MICROSCOPY; Microbial Sensitivity Tests; 3. Good health; PHENOTYPIC RESISTANCE; Klebsiella pneumoniae; 03 medical and health sciences; PHOTOACTIVE MOLECULES; Microscopy, Fluorescence; Photochemotherapy; https://purl.org/becyt/ford/1.6; Drug Resistance, Bacterial; Pseudomonas aeruginosa; Escherichia coli; Single-Cell Analysis; https://purl.org/becyt/ford/1; ESKAPE PATHOGENS; Propidium

Herein we report a simple fluorescence microscopy methodology that, jointly with four photosensitizers (PSs) and cell viability marker, allows monitoring of phenotypic bacterial resistance to photodynamic inactivation (PDI) treatments. The PSs, composed BODIPY dyes, were selected according their ability interact the wall photoinactivating mechanism involved (type I or type II). In first approach, heterogeneity allowing bacteria persist during PDI treatment was evaluated in methicillin-resistant Staphylococcus aureus (MRSA) Escherichia coli as Gram-positive Gram-negative models, respectively. By means propidium iodide (PI), monitored spatiotemporal resolution at single bacterium level. All PSs effective inactivating pathogens; however, cationic nonhalogenated PS (compound 1) surpassed others capable E. even under optimal growth conditions. Compound 1 further tested on two other strains, Pseudomonas aeruginosa Klebsiella pneumoniae, outstanding results. strains used here are well-known ESKAPE pathogens, which leading cause nosocomial infections worldwide. Thorough data analysis individual survival times revealed clear variation expressed that affected PI permeation thus its intercalation DNA. For same sample, death may vary from seconds hours. addition, incorporation time is also parameter governed by characteristics microbes. Finally, demonstrate results gathered for provide direct unique experimental evidence supports time-kill curve profiles.