Foot infections are a major cause for hospitalization of patients with diabetes. Foot ulceration and infection are risks for subsequent amputation. Ischemia, neuropathy, and infection in patients with diabetes combine to produce tissue necrosis and ulcers. Diabetic foot infections are generally polymicrobial in nature.
Early recognition of lesions and prompt initiation of appropriate antibiotic therapy, as well as aggressive surgical debridement of necrotic soft tissue and bone, and a modification of host factors (i.e., hyperglycemia, concomitant arterial insufficiency) are important for successful outcome.
A recent study, published in the May-June issue of Journal of Diabetes and its Complications, evaluated the bacteriology of diabetic foot ulcers at the Adan teaching hospital, Ministry of Health in Kuwait, Kuwait. The relative frequency of bacterial isolates cultured from community-acquired foot infections that were not exposed to antimicrobial agents for 30 days were studied. In addition, the bacterial comparative in vitro susceptibility to the commonly used antibacterial agents was assessed.
During the study, the infected wounds of 86 consecutive diabetic patients were cultured. The patients did not receive antimicrobial therapy 30 days prior to taking the cultures. The specimen was cultured using aerobic and anaerobic microbiological techniques. Isolates were tested for susceptibility to commonly used antimicrobial therapy.
S. aureus and P. aeruginosa were found to be the most common causes of diabetic foot infections.
Anaerobic organisms, majority of them were bacteroids, are still a common cause for infection, although the prevalence is less. These wounds may require use of combined antimicrobial therapy for initial management. Among the gram-negative enteric bacilli, P. mirabilis was the most frequently seen, followed by Escherichia coli and Klebseilla. Imipenem, meropenem, and cefepime were the most effective agents against gram-negative organisms. Vancomycin was the most effective against gram-positive organisms.
The authors suggest that while choosing an antimicrobial for the treatment of diabetic foot infections, one should consider the spectrum of causative organisms, their resistant patterns, efficacy, and safety. Awareness of the causative organisms in diabetic foot infections and their antimicrobial susceptibility pattern is essential for the institution of antimicrobial therapy.