Bacteriological study of diabetic foot infections

The polymicrobial nature of diabetic foot infection has been well documented in the literature. Patients with diabetic foot infection not exposed to antibiotics are not well studied before. The relative frequency of bacterial isolates cultured from community-acquired foot infections that are not exposed to antimicrobial agents for 30 days is studied. In addition, the bacterial comparative in vitro susceptibility to the commonly used antibacterial agents is assessed.

This is a prospective study in which the infected wounds of 86 consecutive diabetic patients seen in the diabetic foot clinic in Adan Teaching Hospital were cultured when visiting the clinic. 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.

Staphylococcus aureus was the most common isolate, being recovered from 38.4% of cases. Other organisms were Pseudomonas aeruginosa (17.5%) and Proteus mirabilis (18%), anaerobic gram-negative organisms (10.5%), mainly Bacteroides fragilis. Imipenem, meropenem, and cefepime were the most effective agents against gram-negative organisms. Vancomycin was the most effective against gram-positive organisms.

S. aureus and P. aeruginosa were the most common causes of diabetic foot infections. Anaerobic organisms are still a common cause for infection, although the prevalence is less. These wounds may require use of combined antimicrobial therapy for initial management.