Exploring the Microbiota of Diabetic Foot Infections With Culturomics

Joanne Jneid, Nadim Cassir, Sophie Schuldiner, Nathalie Jourdan, Albert Sotto, Jean-Philippe Lavigne, Bernard La Scola

The purpose of this prospective observational study was to evaluate the richness and diversity of bacteria in samples from diabetic foot infections using a culturomics approach. Bacterial culture findings from wound samples were analyzed together with clinical characteristics and treatment outcomes. We included 43 patients admitted to a French referral center with a moderate to severe diabetic foot infection. The 30,000 colonies identified yielded 53 different bacterial species. The global α-Shannon diversity was 3.34 and the bacterial richness per patient was 4 ± 2. Of all the identified bacterial species, 19 (35.8%) had never been previously cultured or identified by molecular methods from diabetic foot ulcers. Most of the samples were polymicrobial (N = 38; 88.3%). Of all the isolated species, the most prevalent were Staphylococcus aureus (N = 28; 52.8%), Enterococcus faecalis (N = 24; 45.2%), Enterobacter cloacae (N = 12; 22.6%), Staphylococcus lugdunensis (N = 10; 18.7%), Staphylococcus epidermidis (N = 6; 11.3%), Proteus mirabilis (N = 6; 11.3%), and Finegoldia magna (N = 5; 9.4%). The only factor associated with wound improvement after a 1-month follow-up was the presence of E. faecalis (p = 0.012) when compared with patients without wound improvement. This study confirms the complementary role of culturomics in the exploration of complex microbiota. Further studies on a larger scale are needed to fully understand the clinical importance of the microbiota of diabetic foot infections.