Effect of amoxycillin and doxycycline on function of human granulocytes tested in vitro and on chemotaxis of granulocytes from rabbits given the two antibiotics

The effects of some antibiotics on polymorphonuclear leukocyte functions of elderly patients in vitro before and after zinc supplementation

The effects of ciprofloxacin, cefodizime, rifampicine, doxycycline and cefodizime + rifampicine combination on polymorphonuclear leukocyte (PMN) functions (phagocytosis and intracellular killing activity) were investigated in vitro in elderly patients and compared with those of healthy young volunteers before and after zinc supplementation. PMNs of 13 elderly hypertensive patients and 10 healthy young volunteers were isolated by Ficoll-Hypaque gradient centrifugation method from venous blood with EDTA. The subjects were given 22 mg/daily/oral zinc supplementation for 1 month. Serum zinc levels before and after supplementation were measured by flame atomic absorbtion spectrophotometer and the effects of each drug on PMN functions at therapeutic concentrations were investigated. Ciprofloxacin significantly increased the PMN's phagocytic activity of elderly patients (p = 0.002) before zinc supplementation and significantly increased both PMN functions of elderly patients (p = 0.002) after zinc supplementation. The same antibiotic significantly increased both PMN functions of healthy young volunteers (p = 0.005 and p<0.05, respectively) before and after zinc supplementation when compared with the control (drug-free). Cefodizime significantly increased the PMN's phagocytic activity of elderly patients (p = 0.003, p = 0.002) before and after zinc supplementation when compared with the control (drug-free). It also significantly increased both PMN functions of healthy young volunteers (p = 0.005 and p<0.05, respectively) before and after zinc supplementation when compared with the control (drug-free). Doxycycline significantly increased PMN's intracellular killing activity of healthy young volunteers before zinc supplementation (p<0.05) when compared with the control (drug-free) values. Rifampicine significantly decreased PMN's phagocytic activity of elderly patients (p<0.05) after zinc supplementation. Cefodizime+rifampicine combination significantly increased PMN's phagocytic activity at therapeutic concentrations of healthy young volunteers (p = 0.005) before zinc supplementation and PMN's phagocytic activity of elderly patients (p<0.05) after zinc supplementation when compared with the control (drug-free). Consequently, in the present study from the antibiotics ciprofloxacin, cefodizime and cefodizime + rifampicine combination, which are accepted as biological response modifiers have demonstrated stimulatory effects by significantly increasing polymorphonuclear leucocyte functions (phagocytosis and/or intracellular killing activity) of elderly patients and healthy young volunteers in vitro before and after zinc supplementation. Additionally zinc supplementation has more immunostimulatory effects on PMN functions of healthy young volunteers than elderly patients.

Amoxycillin/clavulanic acid combinations increase transmigration of leucocytes through endothelial cell monolayers: endothelial cells play a key role

Postoperative inflammation is still viewed as an unresolved problem. During inflammation, leucocytes play a tremendous role and migrate from intravascular spaces into the tissue to attack microorganisms. Different agents, e.g. anaesthetic drugs, are able to influence leucocyte recruitment. Previous studies have investigated the influence of amoxycillin on chemotaxis of leucocytes alone. The aim of our study was to examine the effect of amoxycillin/clavulanic acid (co-amoxiclav) on leucocyte migration through endothelial cell monolayers (ECMs). Human umbilical endothelial cells were cultured on microporous membranes, achieving a monolayer. Polymorphonuclear neutrophil leucocytes (PMNLs) were used in a migration assay. The numbers of untreated PMNLs migrating through untreated ECMs were used as control and set as 100%. PMNLs and/or ECMs were pretreated with co-amoxiclav using clinically relevant as well as higher and lower concentrations. Co-amoxiclav was able to increase PMNL migration through ECMs significantly (P<0.05) when both cell types were treated (291+/-18.7%). When PMNLs or ECMs were treated alone, it could be shown that ECMs were more affected than PMNLs. The greatest effect was shown when both cell types, PMNLs and ECMs, were treated. In conclusion, co-amoxiclav was identified as a potent drug to increase leucocyte transmigration through ECMs. ECMs were also critically involved. Co-amoxiclav also affects endothelial cells.

beta-Lactam antibiotic modulation of murine neutrophil cytokinesis

Fourteen cephalosporins, 11 penicillins and 1 monobactam were evaluated for their in vitro modulation of murine neutrophil cytokinesis. As a result, the beta-lactam antibiotics were placed into 6 groups based on their effect on random (R) and FMLP-directed (D) migration [Group 1 (no effect): cephalosporin C; Group 2 (R-->D decreases): cloxacillin, cefotaxime, ceftazadime, cefuroxime, cephalothin, cephapirin, cephadine, nafcillin, piperacillin, ticarcillin, ampicillin, oxacillin, aztreonam; Group 3 (R increases D-->): cephaloridine; Group 4 (R increases D increases): cefsulodin; Group 5 (R increases D decreases): cefoperazone, cefoxitin, ceftriaxone, 6-amino-penicillanic acid; Group 6 (R decreases D decreases): cefadroxil, cefazolin, penicillin G, methicillin]. Trypan blue exclusion studies showed that inhibition of R and D by Group 6 beta-lactam antibiotics is not due to overt cytotoxicity. beta-lactam antibiotics inhibiting D also increased neutrophil adherence to plastic at a concentration of 1000 microM. Finally, the [Ca++] inhibitor chlorpromazine significantly abrogates beta-lactam- and FMLP-directed migration at a test concentration of 1 microM.

Effect of an in vivo immunostimulant treatment on PMN functions: interaction with antibiotics in vitro

The in vivo effect of immunostimulant treatment, bacterial ribosomes together with membranal proteoglycans (three tablets and three sprays daily during 4 days) in combination or not with in vitro amoxicillin or josamycin (range 5-50 micrograms/ml), has been studied on three related functions of polymorphonuclear cells (PMN) isolated from human blood: adhesion, spontaneous and oriented migration. The immunostimulant treatment always induces an increase of the three parameters. A positive effect of high concentrations of amoxicillin could be also observed on adhesion and gives rise to a great additional impact by associating it with immunostimulant treatment (control: 8.26 PMN/field; assay: 51.55 PMN/field). Spontaneous and oriented migration are not very altered by in vitro antibiotics. A very significant decrease of chemotaxis has been only observed with 50 microgram/ml of josamycin. However, the immunostimulant treatment compensates for this negative effect. The real increase in PMN activation produced by the immunostimulant treatment might extend its indications beyond prevention during antibiotherapy, for example in the acute phase of respiratory infections.

Antibiotics and human monocyte function. II. Phagocytosis and oxidative metabolism

The influence of thirteen commonly used antibacterial drugs on the phagocytic and oxidative burst responsiveness of human blood monocytes in vitro was investigated. Cefotaxime and rifampicin produced a significant inhibition of monocyte oxidative metabolism at therapeutic concentrations with increasing inhibition at higher concentrations. The effect of rifampicin was irreversible, which may reflect intracellular accumulation of the drug. Tetracycline, clindamycin, chloramphenicol and tobramycin at high concentrations produced a significant inhibition of monocyte superoxide anion release after stimulation, whereas normal therapeutic concentrations produced insignificant inhibition. Benzylpenicillin, ampicillin, fusidic acid, metronidazole, ofloxacin, sulfamethoxazole and trimethoprim did not alter monocyte oxidative metabolism in vitro. Phagocytosis of yeast cells was significantly suppressed by high concentrations of tobramycin, but otherwise unaffected by the drugs mentioned. These observations suggest that cefotaxime and rifampicin may interfere with blood monocyte oxidative metabolism in vivo, whereas it can be expected that at normal dosage it is unlikely that the other drugs will affect monocyte phagocytosis and oxidative burst activity.

Inhibitory effect of tetracycline and doxycycline on resistance of mice to infection with a tetracycline-resistant strain of Listeria monocytogenes

By transposon mutagenesis a tetracycline-susceptible strain of Listeria monocytogenes (MIC 1 mg/l. for tetracycline and 0.25 mg/l. for doxycycline) was rendered resistant (MIC 64 mg/l. for tetracycline and 16 mg/l. for doxycycline). Infection of mice with this resistant strain led to an acute infection. Treatment with 2 x 2 mg tetracycline per day did not influence the course of infection during the first 3 days, indicating that the nonspecific resistance, mediated mainly by macrophages and granulocytes, was not affected by this treatment. The second phase of infection, characterized by a continuous resistance to infection due to macrophages activated by T-lymphocytes was, however, definitely hampered. Even acquired immunity to a secondary infection was impaired by treatment with tetracycline, indicating that cell-mediated immunity can be blocked. The course of infection of athymic, nude mice which are unable to build up a cell-mediated immune response, was not affected by tetracycline treatment. Doxycycline expressed the same activities as tetracycline.

Effect of doxycycline on oxygen-dependent killing mechanisms of human neutrophils

The effects of doxycycline on neutrophil adhesivity, ingestion rate, and oxidative burst by particle and soluble compounds have been analyzed. The rate of bacterial ingestion by neutrophils as well as its subsequently particle-induced oxidative burst comprising oxygen uptake, hydrogen peroxide and superoxide anion productions, and iodination were all inversely correlated to doxycycline concentration included in the assay medium. The neutrophil oxidative burst induced by phorbol myristate (a soluble stimulant) was also inversely correlated to doxycycline concentration. Drug effect was observed at lower concentrations when the neutrophil stimulant was a soluble compound than when it was particles. In contrast doxycycline did not affect neutrophil adhesivity to either nylon fibers or Petri dishes. Further studies are needed to assess whether the activity of the drug on the neutrophil is due only to its ability to chelate calcium and magnesium or to other properties.