An Investigation of Pseudomonas Aeruginosa Cyan Fluorescence with a Bacterial Fluorescence Imaging Device

Background: Chronic wounds are a current area of major clinical concern, resulting in immense morbidity and mortality of a large patient population annually. These wounds do not typically respond to normal courses of antimicrobial treatment and often require drastic therapies, including amputation of the affected limb. Many different bacterial species are known to cause infections in chronic wounds, with Pseudomonas aeruginosa often playing a major role in these wounds’ virulence and persistence.

Methods: A handheld fluorescence imaging device that illuminates a wound with safe violet (405 nm) light can be used to detect the fluorescent properties of many chronic wound pathogens. This can aid in real-time visualization and direct specimen sampling. Bacterial species that endogenously produce the exoproduct porphyrin (e.g. Staphylococcus aureus, E. coli, Enterobacter cloacae) will fluoresce red when illuminated by the device’s violet light. While P. aeruginosa is a known porphyrin producer, this organism uniquely fluoresces cyan (blue/green) under the violet light clinically, and we have confirmed that it also fluoresces cyan in vitro.  This is due to the production of additional exoproducts with cyan fluorescent properties, such as pyoverdine.

Laboratory Research: We are conducting experiments using mutant bacterial strains of Pseudomonas to elucidate the mechanisms of cyan fluorescence production of P. aeruginosa in order to optimize its detection and utilization of the fluorescence device with P. aeruginosa-infected chronic wounds.