The leading role of antimicrobial agents in modulating the binomial host-microorganism

The current trend of therapy requires the use of antibiotics, wich combine a high level in vitro antibacterial activity with the capacity to act in concert with the immune system in a way the potentiates the host's defence mechanisms. Whilst such additianal effects on the immune system by the antibiotic may be of secondary importance in patients with normal host defence mechanisms, they are of primary importance in patient with depression of the immune system, who are highly susceptible to infections, often difficult to treat even with the current and modern antimicrobial agents. This investigation delineates our own results regarding the impact of some antimicrobial agents such as the most recent beta-lactams, carbapenems, trinems, glycopeptides, quinolones, aminoglycosides and macrolides upon the primary functions of phagocytes, namely human polymorphonuclear granulocytes and macrophages. The ability of the above mentioned drugs to penetrate human phagocytes and the consequence upon subsequent phagocytic ingestion and killing of ingested bacteria, both gram positive and gram negative, are here reported. Moreover the influence exterted by some of these antibiotics either on phagocytic function or on the release of cytokines is illustrated. The beneficial properties of some beta-lactams, which result in "restoring" the depressed phagocyte-dependent response in patients on chronic hemodalysis or in renal transplant recipients, are also focused.