Rol of Lactobacillus plantarum in the treatment of methicillin-resistant Staphylococcus aureus infection in diabetic foot ulcers

Abstract

Diabetic foot infections and delayed wound healing are suggested as the major therapeutic difficulties, due to the increasing global antimicrobial grugs resistance issues. In previous studies we have shown that topical application of Lactobacillus plantarum ( Lp ) cultures favored the healing process . In this work we investigated the effect of Lp on the microbicidal activity of polymorphonuclear cells (PMNs) infected with Staphylococcus aureus (S. aureus).Material and methods: Diabetic patients with ulcers were treated with a topical application of Lp. Biopsies were taken at day 0, 10 and 30 post- treatments. Histopathological and bacteriological studies were performed. At the same time, circulating blood polymorphonuclear cells (PMNs) were isolated from patients. PMNs were stimulated with Lp and culture supernatant to perform the following tests: phagocytosis by flow cytometry, NETosis by fluorometry and microbicial activity. Methicillin-resistant Staphylococcus aureus (S. aureus) isolated from the ulcer was used as infectious strain in all tests. The effect of Lp on the biofilm and cell viability of S. aureus was measure. Results: PMNs from healthy patients was used as control group. Increased phagocytic activity of PMNs was observed in healthy patients only stimulated with LPS (230 ifm vs 402 ifm p <0.001). The same was also observed for diabetic PMNs (210 ifm vs 460 p <0.001). The PMNs of healthy patients showd greater induction of NETosiss (4000 RFU) vs PMN of diabetics (2000 RFU). A significant increase in NETosis (6000 RFU) and microbicial activity of PMNs of diabetics stimulated with Lp or with supernatant was observed. S. aureus were able to produce biofilm. The effect of Lp on mature biofilm, showed significant differences in terms of biomasa reduction when compared to the controls. Conclusions: The treatment with Lp improve wound healing, suppressingof S. aureus infection at wound sites and promoting host innate immunity.