The effect of five antibacterial agents on the physiological levels of serum nitric oxide in mice.

In addition to their action on microorganisms, antibacterial agents have been reported to affect host defense mechanisms. Nitric oxide (NO) that is produced by a number of cell types in the innate immune response is bactericidal, but when produced in excessive amounts it could be detrimental to the host. In this study, five antibacterial agents (gentamicin, tobramycin, imipenem, tigecycline, isoniazid) were compared with respect to their ability to affect NO production in mice. Groups of mice were injected with the different antibacterial agents, and at different time intervals post-injection serum NO levels were determined using the Griess reagent. All the antibacterial agents tested showed a significant effect in reducing NO levels in mice. It could be hypothesized that the excessive production of NO in infectious diseases is in most instances suppressed by the antibacterial agent(s) used.