NEW YORK (Reuters Health) – A new study in mice suggests that high glucose levels in the tissues and blood of people with diabetes can make drug-resistant staph infections more aggressive.
Dr. Anthony R. Richardson of the University of Pittsburgh, author of the study, told Reuters Health by phone: “Excess sugar exacerbates the toxicity of individual small MRSA cells, which get smaller and dirty. than when there is a road around.
“Macrophages and neutrophils help fight infections caused by oxidative stress that produces reactive oxygen species (ROS) and nitric oxide,” Dr. Richardson and his team wrote in the journal Science Advances. oxide (NO)”. “Immune cells require glucose to fuel the oxidative burst and must also express the high-affinity glucose transporters-1 and -3 (GLUT -1/-3), while lacking Oxidative flare is the leading immune system defect in people with diabetes,” they added.
In laboratory studies and in a mouse model of streptozotocin-induced diabetes (STZ), the researchers found that macrophages could not generate an oxidative burst without glucose and they did not express GLUT-1 or -3. They also found that S. aureus needs both of its glucose transporters (glcA and glcC) to be sufficiently virulent.
The infection in STZ-treated mice was more severe, with blood glucose levels of at least 300 mg/dL, compared with about 100 mg/dL in untreated mice. At the site of infection, tissue glucose levels were 4-fold higher in STZ-treated mice.
The mechanism that explains the requirement of efficient insulin signaling for phagocytic GLUT-1/-3 expression is still unknown, the authors note. “That said, we can now begin to understand why people with diabetes get staph infections so often.”
The findings underscore the importance of maintaining glycemic control, which can be a challenge for some patients, Dr. Richardson said.
He added: “These patients make up a significant number of patients with diabetes. “You just have to control that sugar and you have to bring it down.”
References: Lack of nutritional immunity in diabetic skin infections promotes Staphylococcus aureus virulence Science Advances 13 Nov 2020: Vol. 6, no. 46, eabc5569 DOI: 10.1126/sciadv.abc5569
Original post: https://www.medscape.com/viewarticle/941524
Translator: Tran Phuong
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