Influence of new quinolones on normal immune capabilities

Oxidative DNA and RNA damage and their prognostic values during Salmonella enteritidis-induced intestinal infection in rats

Emerging evidence suggests that microbial pathogens may induce oxidative stress in infected hosts. The aim of the present study was to investigate the relationship between changes in oxidative stress and intestinal infection with and without antibiotic treatment in animal models. Sprague-Dawley (SD) rats were divided into three groups: rats infected with Salmonella enterica serovar Enteritidis (S. enteritidis), rats infected with S. enteritidis followed by norfloxacin treatment, and the control group. To evaluate oxidative stress changes, levels of 8-oxo-7,8-dihydroguanosine (8-oxo-Gsn) and 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxo-dGsn), which represented oxidative damage to RNA and DNA, respectively, were analysed in urine and tissue samples. In urine, the level of 8-oxo-Gsn increased significantly after oral exposure to S. enteritidis (p ≤ 0.001) and returned to baseline after recovery. Notably, norfloxacin treatment decreased the level of 8-oxo-Gsn in urine significantly (p = 0.001). Changes of 8-oxo-Gsn measured in tissues from the small intestine, colon, liver and spleen were consistent with 8-oxo-Gsn measured in urine. Our study suggested that 8-oxo-Gsn in urine may serve as a highly sensitive biomarker for evaluating the severity of S. enteritidis infection and the effectiveness of antibiotic treatment against infection.

Study of the cytotoxic/toxic potential of the novel anticancer selenodiazoloquinolone on fibroblast cells and 3D skin model

The new synthetically prepared quinolone derivative 7-ethyl 9-ethyl-6-oxo-6,9-dihydro[1,2,5]selenadiazolo [3,4-h]quinoline-7-carboxylate (E2h) showed in our previous study cytotoxic effects towards tumor cells and immunomodulatory activities on RAW 264.7 cell line murine macrophages. E2h may have a potential use as a novel chemotherapeutic agent with immunomodulatory properties and the ability to induce apoptotic death of cancer cells. The aim of the present study was to examine the antiproliferative/cytotoxic activities of E2h on human non-cancer fibroblast BHNF-1 cells and reconstructed human epidermis EpiDerm™. Further the effects of E2h on tissue structure and morphology were examined. Cytotoxic/toxic studies showed that selenadiazoloquinolone is not toxic on normal human fibroblast cells BHNF-1 and dimensional skin constructs EpiDerm™. Evaluation of morphological changes in EpiDerm™ showed no change in the construction and morphology of skin tissue treated by E2h compared to control.

Influence of fluoroquinolones on phagocytosis and killing of Candida albicans by human polymorphonuclear neutrophils

Candida albicans infections often occur during or shortly after antibacterial treatment. Phagocytosis by polymorphonuclear neutrophil granulocytes (PMN) is the most important primarily defence mechanism against C. albicans. Certain antibiotics such as some fluoroquinolones (FQ) are known to influence phagocyte functions. Thus, we investigated the influence of older and newer FQ on the phagocytosis and killing of C. albicans by human PMN paying special attention to CD11b expression of these cells as an indicator of the degree of their activation. In order to obtain comprehensive and comparable results we tested 13 FQ over a wide range of concentrations and in a time dependent manner in a standardized approach. When used at therapeutic concentrations, the FQ tested did not influence to a clinically significant degree the phagocytosis or the killing of C. albicans by human PMN and also not their activation. However, at high concentrations those FQ with cyclopropyl-moiety at position N1 showed increase in CD11b expression and diminished phagocytosis and oxidative burst.

Effect of beta-lactamase inhibitors on normal immune capabilities and their interactions with staphylococcal pathogenicity

The effects of the beta-lactamase inhibitors, clavulanic acid, sulbactam and tazobactam on normal immune responses were investigated. These agents did not interfere with either humoral or cell-mediated immune responses as measured by the hemolytic plaque assay and delayed type hypersensitivity reaction assay respectively. In addition, human polymorphonuclear leukocyte phagocytic activity was not altered by these agents. When these agents were tested for their effect on Staphylococcus aureas adherence to buccal epithelial cells we found that all inhibitors suppressed staphylococcal adherence at therapeutic serum concentrations. Among the inhibitors investigated, sulbactam was found to significantly inhibit the hemolysin production of S. aureus. These data suggest that beta-lactamase inhibitors do not exhibit immunomodulating activity, but they interfere with some of the virulence factors of S. aureus. These findings suggest the advantage of preparations containing these inhibitors.

Ofloxacin. A reappraisal of its antimicrobial activity, pharmacology and therapeutic use

Ofloxacin is a fluoroquinolone whose primary mechanism of action is inhibition of bacterial DNA gyrase. In vitro it has a broad spectrum of activity against aerobic Gram-negative and Gram-positive bacteria, although it is poorly active against anaerobes. Ofloxacin, unlike most other broad spectrum antibacterial drugs, can be administered orally as well as intravenously. Penetration into body tissues and fluids is highly efficient. Clinical trials with orally and intravenously administered ofloxacin have confirmed its potential for use in a wide range of infections, where it has generally proved as effective as standard treatments. Ofloxacin in well tolerated, and in comparison with other available fluoroquinolones is less likely to cause clinically relevant drug interactions. Ofloxacin thus offers a valuable oral treatment (with an option for intravenous administration if necessary) for use in a wide range of clinical infections, but with a particular advantage in more severe or chronic infections when recourse to parenteral broad spectrum agents would normally be required, thereby providing cost savings and additionally allowing outpatient treatment.

Effects of vancomycin, teicoplanin, daptomycin and coumermycin on normal immune capabilities

Vancomycin, teicoplanin, daptomycin, and coumermycin were investigated for immunomodulatory activity on both humoral and cell-mediated immune responses in Balb/c mice. All four antibiotics did not produce any interference with these responses as measured by hemolytic plaque assay and delayed-type hypersensitivity to sheep red blood cells. The administration of these antibiotics for seven days did not affect the peripheral blood leukocyte count or spleen weights. When these antibiotics were tested for their interaction with human polymorphonuclear phagocytic activity, no alteration in this activity was observed. These findings suggest that vancomycin, teicoplanin, daptomycin, and coumermycin may be safely used for the treatment of infections without altering host-defence mechanisms.