In-vitro effects of cefodizime on leucocyte functions and colony formation from granulocyte-monocyte progenitors

Interference of antibacterial agents with phagocyte functions: immunomodulation or "immuno-fairy tales"?

Professional phagocytes (polymorphonuclear neutrophils and monocytes/macrophages) are a main component of the immune system. These cells are involved in both host defenses and various pathological settings characterized by excessive inflammation. Accordingly, they are key targets for immunomodulatory drugs, among which antibacterial agents are promising candidates. The basic and historical concepts of immunomodulation will first be briefly reviewed. Phagocyte complexity will then be unravelled (at least in terms of what we know about the origin, subsets, ambivalent roles, functional capacities, and transductional pathways of this cell and how to explore them). The core subject of this review will be the many possible interactions between antibacterial agents and phagocytes, classified according to demonstrated or potential clinical relevance (e.g., neutropenia, intracellular accumulation, and modulation of bacterial virulence). A detailed review of direct in vitro effects will be provided for the various antibacterial drug families, followed by a discussion of the clinical relevance of these effects in two particular settings: immune deficiency and inflammatory diseases. The prophylactic and therapeutic use of immunomodulatory antibiotics will be considered before conclusions are drawn about the emerging (optimistic) vision of future therapeutic prospects to deal with largely unknown new diseases and new pathogens by using new agents, new techniques, and a better understanding of the phagocyte in particular and the immune system in general.

Interference of antibacterial agents with phagocyte functions: immunomodulation or "immuno-fairy tales"?

Professional phagocytes (polymorphonuclear neutrophils and monocytes/macrophages) are a main component of the immune system. These cells are involved in both host defenses and various pathological settings characterized by excessive inflammation. Accordingly, they are key targets for immunomodulatory drugs, among which antibacterial agents are promising candidates. The basic and historical concepts of immunomodulation will first be briefly reviewed. Phagocyte complexity will then be unravelled (at least in terms of what we know about the origin, subsets, ambivalent roles, functional capacities, and transductional pathways of this cell and how to explore them). The core subject of this review will be the many possible interactions between antibacterial agents and phagocytes, classified according to demonstrated or potential clinical relevance (e.g., neutropenia, intracellular accumulation, and modulation of bacterial virulence). A detailed review of direct in vitro effects will be provided for the various antibacterial drug families, followed by a discussion of the clinical relevance of these effects in two particular settings: immune deficiency and inflammatory diseases. The prophylactic and therapeutic use of immunomodulatory antibiotics will be considered before conclusions are drawn about the emerging (optimistic) vision of future therapeutic prospects to deal with largely unknown new diseases and new pathogens by using new agents, new techniques, and a better understanding of the phagocyte in particular and the immune system in general.

Cefodizime enhances phagocytosis and intracellular killing of Staphylococcus aureus but does not influence polymorphonuclear leukocytes response to fMLP stimulation

The influence of Cefodizime (CDZ) on in vitro activity of polymorphonuclear leukocytes (PMNL) from healthy subjects was assessed. Preincubation with CDZ enhanced phagocytosis and intracellular killing of Staphylococcus aureus by PMNL. Contrary to numerous clinical reports, no significant effect of CDZ preincubation on PMNL response to n-formyl-methionyl-leucyl-phenylalanine was found with respect to intracellular calcium changes, degranulation, hydrogen peroxide production, and chemiluminescence. These results suggest that augmented microbicidal activity of PMNL is not related to the enhanced production of reactive oxygen species in healthy subjects.

Antibacterial agents--phagocytes: new concepts for old in immunomodulation

The possibility that antibacterial agents, primarily directed against microorganisms, also modify host functions is widely recognized. While a knowledge of these non-antimicrobial effects of antibiotics, sometimes considered as 'side-effects', is necessary to prevent antibiotic-associated toxicity, the development of drugs derived from antibacterial agents for use in non-infectious diseases (e.g. motilins and antidiabetic drugs) is a new field of therapeutic research. Interactions between antibacterial drugs and the immune system may contribute to therapeutic efficacy in infectious diseases [1,2]. The immune system itself is a complex pyramid of redundant cellular factors/humoral effectors/mediators, whose fine regulation is just beginning to be unraveled. Phagocytes, ubiquitous and multifaceted cells are key components of cellular immunity, being involved both in immediate defences against non-self targets (pathogens, tumour cells, exogenous molecules, etc.) and in the regulation and triggering of specific immune responses. They are thus, prime targets of immune response modifiers. This review reconsiders the widely explored problem of interactions between antibacterial agents and phagocytes, focusing on future prospects in both infectious and non-infectious diseases.

In vitro effect of cefodizime, imipenem/cilastatin and co-trimoxazole on dexamethasone and cyclosporin A depressed phagocytosis

Phagocytosis is an important part of the host defense against infection. Antibiotics can influence phagocytic function. In the present study, leukocyte metabolic response to phagocytic challenge by latex was assessed in relation to in vitro addition of cotrimoxazole, imipenem/cilastatin, cefodizime, dexamethasone (DXM), and/or cyclosporin A (CsA). Using latex particles as phagocytic challenge, glucose-1-14C utilization and 14CO2 production were measured by liquid scintillation counting. The phagocytic response was impaired by in vitro addition of DXM or CsA and this setup was used as an experimental model of immunodepression. The addition of co-trimoxazole to control samples (without DXM or CsA) depressed the response to latex challenge, whereas imipenem and cefodizime had a neutral effect. In the presence of DXM, co-trimoxazole induced a further decrease. The depressive effect of DXM was partially neutralized in the presence of cefodizime. With CsA depression, co-trimoxazole also induced a further decrease, imipenem had a neutral effect, while cefodizime partially restored the CsA suppressed reaction. Co-trimoxazole depressed the phagocytic response, imipenem had a neutral effect, whereas cefodizime restored the experimentally induced immunosuppression.