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

Abstract

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.

The association between bacteria and outcome and the influence of sampling method, in people with a diabetic foot infection

“…The latter probably because gram-negative bacteria are always interpreted as pathogenic bacteria and treated accordingly. The association we found, is in line with the retrospective studies of Lipsky et al and Shaheen et al [ 34 , 35 ]. It is unclear whether gram-negative bacteria increase the risk of mortality directly or indirectly.…”

“…Our study confirmed these results, as profile 1 (consisting of Staphylococcus aureus and Streptococcus) and 3 (gram-negative bacteria), were most frequently cultured. In accordance with other studies we found that Streptococcus and Staphylococcus aureus (profile 1) do not increase amputation or mortality risk [ 7 , 8 , 34 , 35 ]. Possible explanations are: the type of infection these bacteria cause, usually acute and mild, as a result of which infection will be recognised in an early stage and treatment starts promptly.…”

“…Cultures were significantly associated with a higher mortality risk. do not increase amputation or mortality risk [7,8,34,35]. Possible explanations are: the type of infection these bacteria cause, usually acute and mild, as a result of which infection will be recognised in an early stage and treatment starts promptly.…”

Common Pathogens Isolated from Infected Diabetic Foot Ulcers at King Abdulaziz University Hospital, Saudi Arabia: A Retrospective Study

“…Our findings are also consistent with those of similar studies conducted in Kuwait and Lebanon, which found that gramnegative bacteria are more commonly isolated from DFIs, with Escherichia coli being the most common [21,22]. In contrast, Al Ayed et al conducted a study in 2018 on 126 patients aged 40-70 years at the Prince Sultan Military Medical City in Riyadh, Saudi Arabia, using a swab culture method for microbiological testing and reported that Staphylococcus aureus was the most commonly isolated organism, followed by Pseudomonas aeruginosa [23]. The high incidence of gram-negative DFI in our region can be explained by multiple theories.…”

Recent advances of the nanocomposite hydrogel as a local drug delivery for diabetic ulcers

“…The decomposition products of diabetic ulcer skin tissue and the persistent high-glucose environment provide an excellent culture medium for the growth and reproduction of bacteria. A large number of bacteria enter the human body through the wound and go deep into the tissue, leading to sepsis and even death ( Shaheen et al, 2021 ; Xie et al, 2022 ). Early, active and effective control can prevent chronic infection and accelerate wound healing ( Han and Kang, 2013 ).…”