Associação do perfil microbiológico com os graus de infecção e os estágios de risco da Classificação Wound, Ischemia, and foot Infection (WIfI), amputação e óbito em pacientes internados devido à úlcera infectada do pé diabético

Abstract

Introduction: infection, ischemia and wound are the three factors associated with lower limb major amputation. However, more than half of amputations in patients with diabetes mellitus are attributed to the infection. The Wound, Ischemia, and Foot Infection (WIfI) Classification System stratifies the three factors in degrees of severity to allow guiding therapeutic priorities in these patients. Objective: to evaluate the association between advanced microorganisms with the degrees of infection and the risk stages of amputation in the WIfI Classification, major amputation and death in hospitalized patients with diabetes mellitus due to infected foot ulcer. Method: prospective cohort study in patients with diabetes mellitus with an infected foot ulcer. Patients were stratified by the WIfI Classification for wound, ischemia and infection in four degrees: grade 0 (none), grade 1 (mild), grade 2 (moderate) and grade 3 (severe) and for very low risk of amputation (stage 1), low (stage 2), moderate (stage 3) and high (stage 4). For statistical analysis, univariate logistic regression was performed with a 5% significance level. Results: 98 participants were studied, totaling 100 infected ulcers located on the foot, between February 2017 and March 2019. The average age was 60.8 years (standard deviation - SD 11.3), with 68.4% being men. It was observed that 35.0%, 60.0% and 5.0% of the limbs had infection grades 1, 2 and 3, respectively. The stages of amputation risk were 15.0% very low, 18.0% low, 33.0% moderate and 34.0% high. The most isolated microbial species was Staphylococcus aureus (23.3%). Proteus mirabilis (Odds ratio - OR 0.1; confidence interval - 95% CI 0.1-0.6; p=0.013), Klebsiella pneumoniae (OR 0.1; 95% CI 0.1-0.9; p=0.039) and Enterobacter aerogenes (OR 0.1; 95% CI 0.1-0.9; p=0.039) were associated with grade 3 infection (compared to grade 2). Carbapenem-resistant bacteria were associated with grade 1 infection (compared to grade 2) (OR 3.6; 95% CI 1.1-11.4; p=0.028) and grade 3 infection (compared to grade 2) (OR 0.1; 95% CI 0.1-0.9; p=0.036). Regarding the risk stages of amputation, Enterococcus faecalis was associated with very low risk [(compared to a moderate risk) (OR 0.1; 95% CI 0.1-0.5; p=0.004) and compared to high risk (OR 0.1; 95% CI 0.1-0.6; p=0.006)] and also with low risk (compared to moderate risk) (OR 0.2; 95% CI 0.1-0.9; p=0.049). Bacteria resistant to third and fourth generation cephalosporins were associated with a very low risk (compared to a moderate risk) (OR 0.2; 95% CI 0.1-0.9; p=0.049). Enterobacter aerogenes was associated with in-hospital death (OR 65; 95% CI 4.0-104.6; p=0.003). No microorganism was associated with amputation. Conclusion: Staphylococcus aureus was the most prevalent bacterium, however, it was not associated with degrees of infection or risk stages. Proteus mirabilis, Klebsiella pneumoniae and Enterobacter aerogenes were associated with severe infections; and carbapenem-resistant bacteria with mild and severe infections. Enterococcus faecalis and bacteria resistant to third and fourth generation cephalosporins were associated with lower risk stages. Enterobacter aerogenes was associated with death. There was no association of microorganism with amputation.