The microbiology of diabetic foot infections: a meta-analysis

Abstract

Background: Diabetic foot ulcers are a common complication of poorly controlled diabetes and often become infected, termed diabetic foot infection. There have been numerous studies of the microbiology of diabetic foot infection but no meta-analysis has provided a global overview of these data. This meta-analysis aimed to investigate the prevalence of bacteria isolated from diabetic foot infections using studies of any design which reported diabetic foot infection culture results.

Methods: The Medline, EMBASE, Web of Science and BIOSIS electronic databases were searched for studies published up to 2019 which contained microbiological culture results from at least 10 diabetic foot infection patients. Two authors independently assessed study eligibility and extracted the data. The main outcome was the prevalence of each bacterial genera or species.

Results: A total of 112 studies were included, representing 16,159 patients from which 22,198 microbial isolates were obtained. The organism most commonly identified was Staphylococcus aureus, of which 18.0% (95% CI 13.8-22.6%; I² = 93.8% [93.0-94.5%]) was MRSA. Other highly prevalent organisms were Pseudomonas spp., E. coli and Enterococcus spp. A correlation was identified between Gross National Income and the prevalence of Gram positive or negative organisms in diabetic foot infections.

Conclusion: The microbiology of diabetic foot infections is diverse, but S. aureus predominates. The correlation between the prevalence of Gram positive and negative organisms and Gross National Income could reflect differences in healthcare provision and sanitation. This meta-analysis has synthesised multiple datasets to provide a global overview of the microbiology of diabetic foot infections that will help direct the development of novel therapeutics.

Keywords: Diabetes; Diabetic foot infection; Diabetic foot ulcer; Meta-analysis; Microbiology; Prevalence.

Fig. 1

Flow diagram of study selection

Fig. 2

The frequency of microorganisms identified by aerobic culture of diabetic foot infection specimens

Fig. 3

A forest plot of the meta-analytic prevalence of the microorganisms identified by aerobic culture of diabetic foot infection specimens. For clarity only genera with a prevalence > 1.0% are plotted, with prevalence data for genera < 1.0% available in Additional file 2

Fig. 4

The frequency of microorganisms identified by aerobic or anaerobic culture of diabetic foot infection specimens

Fig. 5

A forest plot of the meta-analytic prevalence of the microorganisms identified by aerobic or anaerobic culture of diabetic foot infection specimens. For clarity only genera with a prevalence > 1.0% are plotted, with prevalence data for genera < 1.0% available in Additional file 2

Fig. 6

The meta-analytic prevalence of the bacteria most frequently identified by aerobic culture in high-income (HIC) or upper-middle and lower-middle income countries (U/LMIC)