Isolation and characterization of bacteria from diabetic foot ulcer: amputation, antibiotic resistance and mortality rate

BACKGROUND: Diabetic foot ulcer (DFU) is one of the most serious complications of diabetes mellitus with devastating outcomes. Poorly treated DFU leads to osteomyelitis, gangrene and limb amputation. There is an increased risk of mortality for the amputees and increased number of bacterial resistance in survived patients. Struggle on choice of the best antibiotic(s) for DFU is escalating. OBJECTIVES: To determine risk factors associated with mortality in patients with DFU. To investigate bacterial drug resistance in survived or deceased patients around amputation. METHODOLOGY: This is a retrospective cohort study that involved all diabetic patients who had DFU or minor or major amputation at Hebron Governmental Hospital from 2013 to 2020. Antibiotic use and bacterial isolates along with culture and sensitivity test results were retrieved from patients’ profiles and laboratory records. Major outcome of study was survival rate around amputation. Patients who missed test results for FBS or HbAc1, or who had no wound culture were excluded. SPSS version 22 was used to analyze data. RESULTS: Eighty four subjects were included in this study, 64.8 ± 12.58 years old, 63.1% males who had diabetic foot ulcer, minor or major limb amputation between 2013 and 2020 at Hebron Governmental Hospital. Forty tow patients (50%) had diabetic foot ulcer, 28 patients (33.3%) had major limb amputation, and 14 patients (16.7%), succumbed to minor amputation. Average FBS was 292.8 ± 136.33 mg/dl and average HbA1C was 8.55 ± 1.89%. Mortality rate was 9.5%. Using the Chi square test, we found a significant relationship between mortality and type of isolated bacteria, p = 0.033 and between diabetic complications (nephropathy) and mortality, p = 0.033. There was a significant relationship between antibiotic use and mortality, p = 0.04, especially with metronidazole and colistin, if they were used around limb amputation. CONCLUSIONS: Mortality of diabetic patients with DFU was associated with nephropathy and Acinetobacter or E. coli infections.