A new device sheds light on bacteria in wounds
Chronic wounds do not necessarily manifest the same "classic" signs as seen in an acute wound, such as pus, pain, inflammation or redness. But they can still be harboring clinically-significant amounts of bacteria that can eventually become a full-fledged infection, or just stall healing altogether.
This is called a chronic inhibitory bacterial load (CIBL) in the wound care world and until now has been historically difficult to diagnose. Now, a handheld camera-like device can find bacterial hotspots in wounds before they progress to readily visible infections, allowing for earlier and more targeted treatment. Identification of this CIBL and targeted removal/treatment can put stalled wounds back on the track to healing.
Called MolecuLight, the device uses a type of violet light to display where bacterial hotspots exist in a wound. Taking a culture from a wound is inherently inaccurate, as bacteria does not uniformly cover the entire wound bed, according to Patrick J. Flynn, MD, medical director of Cape Cod Healthcare’s Wound Centers in Bourne and Hyannis. Because the device doesn’t require touching the wound, the imaging is completely non-invasive and done right at the bedside. The hotspots of clinically-significant bacterial burden can be accurately located, removed with targeted debridement or cleansing, or sampled via a targeted culture, he said.
The device uses fluorescence to create images showing healthy tissue in green, areas of most bacterial species in red, and the presence of one species, Pseudomonas aeruginosa, in cyan (bright greenish-white).
“In the old days, you were pretty much reliant on what you could see with your eye. And cultures weren’t that accurate,” said Dr. Flynn. “The old methods were going to miss bacteria in a majority of cases, to be honest.” Relying upon "classic" clinical signs of infection was only about 15 percent accurate in chronic wounds, he added.
The MolecuLight device also measures a wound’s area and stores the images, allowing for healing to be tracked. Dr. Flynn said he can show patients an image of their wound, and he adds the pictures to their patient record.
In Use at CCHC
CCHC’s Wound Care Centers have been using MolecuLight for about nine months and are conducting their own in-house study of its effect on wound healing. Images are taken at patients’ initial visits, and at subsequent visits, if not meeting expected healing benchmarks. Standard-care wound treatment goals are 40 percent healed at four weeks and 80 percent healed at eight weeks, he said.
By incorporating this into their practice, the Centers are hoping to improve on those goals, he said.
According to the MolecuLight website, using the diagnostic device can double the number of diabetic foot ulcers (a common type of chronic wound) healed at 12 weeks from a standard-of-care rate of 22 percent to 45 percent, citing a July 7, 2022 paper in Diabetes Care. It also claimed using MolecuLight resulted in a 79 percent reduction in the size of those ulcers in 12 weeks.
By identifying bacterial hotspots before they develop into raging infections, cleaning, debriding and topical antimicrobial treatment can be focused on those areas, reducing the need for systemic antibiotics that affect the entire body. This is especially important for older patients with chronic wounds, as their immune response may be muted, so they may not display clinical signs of infection, Dr. Flynn said.
Use of MolecuLight isn’t covered by many insurance companies, but as the amount of data compiled on its effectiveness grows, perhaps that will change, he said. The manufacturer’s latest version of the device adds thermal imaging to its diagnostic abilities.
“This is illustrative of where the wound care world is going - more bedside diagnostic tools that we never had in the past,” said Dr. Flynn.
