Abstract: Objective To explore the relationship of the severity of diabetic foot infection with the severity of lower extremity vascular disease and disease outcome. 
Methods A total of 113 patients with diabetes and foot infection who were selected. According to the severity of the disease, the patients were divided into four groups: groups A, B, C and D, and the bacteria infection characteristics and disease outcome in four groups were analyzed. 
Results The comparison of age, diabetes course, ABI, and TBI of the four groups of patients was statistically significant(P＜0.05), and as the degree of lower extremity lesions worsened, age, diabetes course, neutrophil levels increased, and ABI and TBI levels decreased. Correlation analysis showed that the degree of lower extremity lesions was positively correlated with age, diabetes course and neutrophils, and negatively correlated with ABI and TBI. The gram-negative bacterial infections of the four groups were different(P＜0.05), and the gram-negative bacterial infections of group C and D were significantly more than those of group A and B(P＜0.05). The infections of group A were mainly non-gram-negative bacteria, and the infections of group B were mainly non-gram-negative bacteria. The comparison of the number of patients with mild infections and severe infections in four groups was statistically different(P＜0.05); the number of mild infections in group A was significantly higher than that in groups B, C and D(P＜0.05). The number of severe infections in group B and D was significantly higher than that in group A(P＜0.05). The number of mixed infections in four groups was statistically different(P＜0.05); the number of mixed infections in group A was significantly lower than that in groups C and D(P＜0.05), and the mixed infection in group B was significantly lower than that in group D(P＜0.05). The number of patients with healing, minor amputation, major amputation and death outcome of four groups was statistically significant(P＜0.05). The number of healed patients in group A was significantly higher than that in group B, C and D(P＜0.05), and the number of small amputations in group A was significantly lower than that in group C and D. 
Conclusion As the degree of vascular disease in the lower limbs of diabetic foot patients increases, the bacterial infection of the foot with gram-negative bacteria increases, the mixed infection increases, the chance of healing decreases, and the chances of small amputation, large amputation and death will increase.

Key words: diabetic foot, bacterial infections, lower extremity vascular disease