Detection of nosocomial pneumonia pathogens using a fluorescence-based device

Background: Early detection of nosocomial pneumonia pathogens is a significant factor in hospital-acquired pneumonia care. This study aimed to determine the autofluorescence properties of five nosocomial pneumonia pathogens using a fluorescence-based device and to establish evidence for clinical guidelines. Methods: The following bacterial strains were assessed: Acinetobacter baumannii (AB), Escherichia coli (EC), Enterococcus faecalis (EF), Klebsiella pneumoniae (KP), and Staphylococcus aureus (SA). The bacteria were cultured separately on tryptic soy agar at 37 °C under aerobic conditions for 168 h. Fluorescence photographs of each species were captured every 24 h using a fluorescence-based device with fixed camera settings. The images were analyzed by measuring the red and green values (R/G ratio) at a central point in each colony, and the R/G ratios were analyzed using the Kruskal–Wallis non-parametric test. Results: KP and SA showed red fluorescence with their R/G values, which were significantly higher than those of the other strains (p < 0.001). In particular, the R/G ratio of KP increased steadily until 72 h of incubation, peaking at 3.65. In addition, AB and EC showed orange fluorescence with higher red ratios than green ratios. EF and SA showed green fluorescence all through 168 h of incubation, with R/G ratio less than 1.0. Conclusions: Nosocomial pneumonia pathogens can be identified and classified via bacterial autofluorescence emission. It is possible to develop a rapid and easy-to-use identification technology based on bacterial autofluorescence for clinical applications.