SLR - April 2018 - Ajay K. Ghai

Influence of Multidrug-Resistant Organism on the Outcome of Diabetic Foot Infection

Reference: Saltoglu N, Ergonul O, Tulek N, Mucahit Y, Ayten K, Gul K, Ayse B, Oznur A, Cagla S. Influence of Multidrug-Resistant Organism on the Outcome of Diabetic Foot Infection. International Journal of Infectious Diseases. 2017.

Scientific Literature Review

Reviewed By: Ajay K. Ghai, DPM
Residency Program: Carilion Clinic/Virginia Tech School of Medicine (Roanoke, VA)

Podiatric Relevance: Multidrug-resistant organisms (MRDOs) are becoming more and more prevalent in diabetic foot infections (DFI). This study aims to examine the clinical outcomes of patients with DFI and possible MDROs. This is essential to study and understand as the outcomes described may be useful for future guidelines in treating DFI, especially in regards to empiric antibiotic therapy when culture results may not be readily accessible.

In this retrospective study; 791 patients with DFI at 19 centers were examined. This was done over a four-year period from 2011 to 2015. Infection severity was defined using IDSA guidelines. Patients with a complicated moderate infection or a severe infection were hospitalized. After discharge, patients were followed up for six months. Cultures and pathology were reviewed to determine the prevalence of certain organisms in DFI. Also examined were readmission rates and infections associated with this population.

Of the 791 patients, 85 (11 percent) had a severe infection, and 291 (36.8 percent) had osteomyelitis. 92.5 percent of patients were hospitalized with an average admission of 21 days. Five hundred thirty-six microorganisms were observed with the most common organisms being S.aureus (20 percent), P.aeruginosa (19 percent) and E.Coli (12 percent). The methicillin-resistant staphylococcus aureus (MRSA) rate among S.aureus isolates was 31 percent. MDRO was present in 21 percent of P.aeruginosa isolates. Extended spectrum beta-lactamase (ESBL) gram negative bacteria (GNB) were seen in 38 percent of E.coli and Klebsiella isolates. The hospital readmission rate was 8 percent. Sixteen percent of patients had a major amputation, and 3 percent of patients died. Significant predictors of fatality were dialysis, Klebsiella infection and chronic heart failure. Among readmitted patients, MRSA was the most common isolated organism with a rate of 21 percent.

Conclusions: This study took place outside the United States, which makes it difficult to know if there is an international correlation between the most common infectious organisms. Antibiograms should be used to determine regional susceptibility of various common infectious agents. This study would support empiric coverage of at least S.aureus and P.aeruginosa if cultures are not able to be obtained, as treating both would allow an almost 40 percent rate of antimicrobial coverage. In the study region, one in five readmissions for DFI revealed MRSA as an infecting agent. This is important to keep in mind as these patients likely failed outpatient antibiotics or have been exposed to prior rounds of antibiotics, increasing the likelihood of antimicrobial drug resistance. Significant predictors of fatality (dialysis, Klebsiella infection and chronic heart failure) are also necessary to keep in mind when treating DFI, as these patients may need more aggressive care.

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