Beneficial effects of dietary arginine supplementation in methicillin-resistant Staphylococcus aureus infected mice

Abstract

To determine any potential benefits of feeding increased amounts of arginine to septic mice, 45 BALB/c mice were randomized into 3 groups. Group A mice were fed 20% casein diet (control), whereas the mice in Groups B and C were given 20% casein diet supplemented with 2% and 4% arginine, respectively. The diets were isonitrogenous and isocaloric. On the 10th day on these diets, each mouse was challenged with 2.0×10 8 colony forming units (CFU) of methicillin-resistant Staphylococcus aureus (MRSA) organisms intravenously and mortality noted for 20 days. The final survival rate in Group A (20%) tended to be lower than the rates in Group B (60%) and Group C (46%) but without significant difference (p>0.05). Of the surviving mice 20 days post inoculation, in Group B, 7 out of 9 (77%) eliminated the organisms as compared to 1 out of 4 (25%) in Group A, and 3 out of 7 (43%) in Group C. The surviving mice in Group B had significantly heavier splenic weight (140±30mg) as compared to Group A mice (90±10mg). The present data suggest that 2% dietary arginine supplementation may be beneficial in offering protection to the mice following MRSA challenge.