Ampicillin alone and in combination with riboflavin modulates Staphylococcus aureus infection induced septic arthritis in mice.

Effects of ampicillin (Amp) in combination with riboflavin on septic arthritis in mice infected with Staphylococcus aureus have been reported. Ampicillin was given at 100 mg/kg after 24 h of infection, followed by riboflavin (Ribo) at 20 mg/kg body wt, after 2 h of Amp treatment. Mice were sacrificed at 3, 9, 15 days post infection (dpi). Combined treatment of infected mice with ampicillin and riboflavin eradicated the bacteria from blood, spleen and synovial tissue and showed a significant gross reduction in arthritis, reduced serum levels of TNF- and IFN-. S. aureus infected mice exhibited higher synovial TNF- and IL-6, which was also reduced by ampicillin and riboflavin treatment. S. aureus infected mice showed a disturbed antioxidant status measured in terms of cellular anti-oxidants like reduced glutathione and anti-oxidant enzymes such as superoxide dismutase and catalase and were ameliorated when the animals were co-treated with ampicillin along with riboflavin. Results of the study showed that combined treatment with anti-oxidant and antibiotic may protect from staphylococcal arthritis and may ameliorate oxidative stress caused by S. aureus infection.

Use of minocycline in viral infections.

Repurposing of old drugs is a useful concept as it helps to minimize costs associated with the research and development of a new drug. Minocycline, a common second generation antibiotic, has been shown to possess several other beneficial effects other than its intended uses. The antiviral role of minocycline has generated considerable interest from the last decade. It was first shown to be beneficial in preventing human immunodeficiency virus (HIV) infections and later it was reported to improve cognitive deficiencies associate with neuroAIDS. However, its antiviral efficacies are not limited to retroviruses alone. In animal models or in vitro systems of flaviviral infections (especially Japanese encephalitis virus), minocycline has been shown to be highly effective. However, not all effects are based on direct inhibition of viral replication. The general anti-inflammatory and immunomodulatory properties of minocycline are also responsible in part, in imparting the protective effects. Owing to the fact that minocycline is well tolerated by most people and that the drug has nearly 40 years history of usage, it is an exciting prospect to try out in other viral infections.