Impact of the bacteriology of diabetic foot ulcers in limb loss

Abstract

Infections in feet of patients with diabetes mellitus is common, complex and costly. The aim of this study to investigate the isolated microorganisms in infected diabetic foot ulcers, and the impact of these infectious agents in limb loss in a tertiary medical center in Mexico City. We conducted a retrospective review in diabetic patients with infected foot ulcers from 1997 to 2014. Diabetic foot was defined according to the World Health Organization (WHO), the bacteriology of wound cultures and the impact of microorganisms in limb loss (major amputation) was studied. Patient's demographics, comorbidities, wound characteristics, and other factors associated in clinical outcomes were determined. A total of 165 subjects with soft tissue infections and/or osteomyelitis and positive cultures were included. One hundred and five (64%) were male, with a mean age of 60 year old +/- 15. One hundred fifty-nine (96%) had Type 2 diabetes mellitus, 68 (41%) history of peripheral arterial disease (PAD) and 97 (59%) patients had osteomyelitis. In 89 patients (54%), cultures were polymicrobial and one single organism was isolated in 76 cultures (46%). During the follow up, 96 (58%) patients preserved their limbs and 69 (42%) required major amputation (above or below knee). Sixty percent of patients that suffered from limb loss had polymicrobial culture (p = 0.13). Growth of Escherichia coli and Enterococcus faecium (p = 0.03) and E. coli and Morganella morgagnii (p = 0.03) was associated to limb loss. Among monomicrobial cultures, infections associated with Proteous mirabilis had higher rate of progression to limb loss (p = 0.03). PAD was associated to limb loss (p = 0.001). Management of diabetic foot requires a multimodality approach. In this study, in patients that received appropriate antibiotic therapy and optimal surgical management, we observed that history of PAD, polymicrobial and isolated P. mirabilis infections were variables associated with higher rate of limb loss.

Bacterial Prevalence and Antibiotic Resistance in Clinical Isolates of Diabetic Foot Ulcers in the Northeast of Tamaulipas, Mexico

“…With similar results, a study reported by Aragón-Sánchez et al, 28 found that the presence of gram-negative bacteria in infected diabetic ulcers was significantly associated with more severe infections. We suggest that while S. aureus is predominant in diabetic foot infections, gram-negative bacteria 29 ; for example, Enterobacter genus, can play an important role in the colonization/infection of certain tissues; however, studies with a larger sample number and more robust in terms of statistical analysis could establish guidelines regarding the role colonizers of this type of bacteria in DFUs.…”

Microbial Host Interactions and Impaired Wound Healing in Mice and Humans: Defining a Role for BD14 and NOD2

“…Human skin is colonized by a diverse array of bacteria and microbes that generally live in harmony with the host, yet overgrowth of commensal species or pathogen infection can negatively affect healing (Grice and Segre, 2012a, 2012b). Although the precise relationship between the microbes and healing remains unclear, diabetic wounds are thought to be colonized by distinct microbiota, including increased Pseudomonas aeruginosa, compared with normally healing wounds (Grice et al, 2010;Hinojosa et al, 2016;Price et al, 2011). However, not all wounds fail to heal, and it remains unclear whether an altered skin microbiota is associated with a predisposition to delayed healing.…”

<p>Antimicrobial Susceptibility Testing and Phenotypic Detection of MRSA Isolated from Diabetic Foot Infection</p>

“…One of the most serious complications of this disease is diabetic foot infection (DFI), 1 which is caused by single or multiple microorganisms. 2 Aerobic Gram-positive cocci, such as Staphylococcus aureus, are the predominant organism responsible for acute DFI. However, polymicrobial isolates are mostly observed in chronic wound infections.…”