Diabetic Foot Infection Control With Ultraviolet Light

Diabetic foot infections arising from ulcerations are the largest non-traumatic cause of lower extremity amputations. Many of the infections are acquired by improper care of the ulcer as well as failure to protect the open wound from contaminants. Contributing factors include peripheral neuropathy and vascular disease, rigid pedal deformities, local trauma and pressure, extensive soft tissue loss, multi-system failure, non-compliance and severe infection. For Podiatrists it is a recurring problem.

The recent Infectious Diseases Society of America (IDSA) Diabetic Foot Infection Guidelines emphasize the following point:

"Aerobic gram positive cocci (especially Staphylococcus aureus) are the predominant pathogens in diabetic foot infections. Patients who have chronic wounds or who have recently received antibiotic therapy may also be infected with gram negative rods, and those with foot ischemia or gangrene may also have obligate anaerobes."

The guidelines specifically note the dated thinking that all DFIs are mixed infections is not evidence based. There is a difference in microbial flora based on the severity of the infection and the presence of comorbidities. Even in the more complicated infections in which a myriad of other organisms may be isolated, their importance as primary pathogens needing antibiotic coverage is debatable. Many represent colonization only.

MRSA Continues To Be Evolving Problem

While the number and types of true pathogens in the majority of DFIs may be limited to Staphylococcus and Streptococcus, it does not mean that the clinician can rest assured that traditional therapies active against these two organisms will be enough. MRSA as well as VRE are emerging as serious threats to the diabetic patient.

The traditional therapies of systemic antibiotics often compromise the healing of the ulcer itself as well as many of the topical agents that are branded generics of common ingredients such as silver, povidone iodine, and other traditional topicals.

"Wound Healing, Alternatives in Management" by Kloth, McCullouch also point out that many chronic wounds are not chronic in nature but are acute injuries that are consistently reinjured in treatment and appear to be chronic. An example of improper treatment would be the use of sterile gauze as filler yet the gauze is allowed to dry out and the results are the gauze now adheres to the new granulating tissue and each removal destroys the new growth and sets back the healing while exposing newly injured tissue to external contaminants. Eschar develops, which is a wonderful breeding ground for MRSA and other pathogens, because the top cells die from dehydration and the dead tissue becomes the eschar.

In the past five years, there has been a seemingly logarithmic growth in the incidence of methicillin resistant Staphylococcus aureus (MRSA) as a pathogen in the diabetic foot. This organism was once associated only with nosocomial infections but now community-acquired strains of MRSA have become common in DFI cases. While it is outside the scope of this feature to review MRSA in detail, it is important to examine the situation in the diabetic foot.

As recently as 1996, Goldstein reported that 20 percent of the staphylococcal isolates from his diabetic foot population in California were methicillin resistant.4 In 1999, Tentolouris showed 40 percent of the staphylococcal isolates in their diabetic foot clinic in the United Kingdom were methicillin resistant.5 In 2003, the same group published a follow-up study entitled "Methicillin resistant Staphylococcus aureus in the diabetic foot clinic: A worsening problem."6 Although the absolute percentage of MRSA among their staphylococcal isolates only increased to 42.2 percent, the number of patients that actually presented with MRSA doubled. Fortunately, their study found many of these MRSA isolates could be treated effectively with debridement, topical therapy and isolation.

Unfortunately traditional treatments continue to be used and the population of drug resistant strains of "super germs" continues to develop faster than new antibiotics. This is not necessary.

Ultraviolet C- range ( 254 nm) has consistently shown the ability to not only kill all forms of pathogens, especially bacterial, but no bacteria has ever been capable of mutating or avoiding the lethal effects of UVC. Ultraviolet C range is easy for the patient to self-treat and one of the lamps is FDA approved for dermatological applications such as destroying pathogens on the skin surface thus avoiding new contamination. Total treatment time is less than 90 seconds. Cost once device purchased or rented is only the cost of electricity for a 4 watt bulb for 90 seconds, or less than a penny.

Ultraviolet can be used for not only topical treatment where the bacteria has localized but is also indicated for systemic infections.

Tens and Interferential electrotherapy can be used post Ultraviolet treatment to facilitate faster growth as well as controlling the swelling and increasing blood flow to the foot.

There are many tried and true therapies such as ultraviolet that will stop the necessity of amputation for the patient with a diabetic foot infection or any other foot wound that becomes infected.