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The in vitro effect of macrolides at concentrations below the minimum inhibitory concentration (sub-MIC) on the interaction between Pseudomonas aeruginosa biofilm and human polymorphonuclear leukocytes (PMNs) was investigated by using a chemiluminescence assay. The PMN response to either mucoid or nonmucoid P. aeruginosa biofilm was strongly reduced compared with the response to planktonic bacteria (p < 0.01, p < 0.001, respectively). When biofilms were treated with erythromycin, clarithromycin, roxithromycin and azithromycin prior to incubation with PMNs, the chemiluminescence response was markedly enhanced as compared to untreated controls, and a dose-dependent effect was noted over the range of sub-MIC concentrations studied. In general, macrolides appeared to be slightly more active against mucoid biofilm. Azithromycin was shown to be the most active macrolide against P. aeruginosa biofilms. However, the treatment with sub-MICs of rokitamycin did not have any effect. On the other hand, treatment of planktonic bacteria with macrolides before being exposed to the PMNs did not affect the chemiluminescence response as compared to untreated controls. These findings suggest that macrolides inhibiting the biofilm formation of P. aeruginosa may facilitate the phagocytosis of bacteria by PMNs. more...

The influence of azithromycin on biofilm formation by Pseudomonas aeruginosa , a cause of refractory chronic respiratory tract infection, was investigated. Alginic acid produced by a

A total of 34 patients with intractable chronic respiratory tract infections were treated with isepamicin and/or piperacillin in different dosage regimens. A comparison of the bacteriological effect using a cross over method showed a reduction in the count of Pseudomonas aeruginosa in sputum in the group receiving once-a-day isepamicin combined with piperacillin, compared with the twice-a-day combined administration. A comparison of the clinical and bacteriological efficacy between the different regimen groups revealed no noticeable difference. The clinical effect of this regimen is comparable to the conventional regimen, but has the advantages of a safer dosage and ease of administration. more...

To investigate the in vivo effect of antimicrobial agent on neutrophil chemiluminescence and serum opsonic activity, cefbuperazone sodium (CBPZ) was administered to healthy male volunteers via an intravenous drip. A peripheral blood sample (10 ml) was collected 7 times: prior to injection, then 1, 3, 6, 9, 12 and 24 h after injection. Neutrophil chemiluminescence and serum opsonic activity was measured by the simultaneous multiple measurement system based on luminol-dependent chemiluminescence and indicated by peak height and peak time. Neutrophils were activated at hour 1 from the point of view of peak height and statistical significance was observed. The fluctuation of serum opsonic activity was small and statistical significance was not observed. CBPZ has an in vivo effect on neutrophils which was not supposed from in vitro study. more...