Outbreak of postoperative empyema caused by Serratia marcescens in a thoracic surgery unit.

An increase in the number of cases of postoperative empyema due to S. marcescens was recognized in the intensive care unit (ICU) of our Division of Thoracic Surgery between 3 and 19 March 2013. Pleural samples from patients and environmental samples from the operating room and ICU were obtained. A total of eight isolates (six from pleural fluid and two from portable suction devices in ICU) were identified as Serratia marcescens. All isolates were found to be identical by repetitive sequence-based polymerase chain reaction. This is the first report of an outbreak caused by S. marcescens related to a contaminated portable suction machine.

Endothelium-dependent induction of vasorelaxation by Melissa officinalis L. ssp. officinalis in rat isolated thoracic aorta.

In the current study, vasorelaxant effect produced by the aqueous extract of Melissa officinalis L. ssp. officinalis (MOO) (Lamiaceae) and its possible mechanism in isolated rat aortic rings precontracted with phenylephrine were examined. In the first series of experiments, effect of MOO on the baseline and phenylephrine (10(-5)M) precontracted arteries was investigated, while in the second group of experiments, endothelium intact or endothelium denuded effect was determined. The agents used were N(omega)-nitro-L-arginine (L-NAME), an irreversible inhibitor of nitric oxide (NO) synthase, indomethacin (10 microM), a cyclooxygenase (COX) inhibitor, and glibenclamide (10 microM), an ATP-sensitive potassium channel blocker. The extract was found to exert a vasorelaxant effect and rosmarinic acid quantity, the characteristic compound of the plant, was analyzed by reversed-phase high-performance liquid chromatography (18.75%), and was further confirmed by LC-MS analysis giving a prominent [M(+1)] molecular ion peak at m/z 365. Total phenol amount in the extract was determined using Folin-Ciocalteau reagent (0.284 mg/mg extract). Vasorelaxant effect of the extract was entirely dependent on the presence of endothelium and was abolished by pretreatment with L-NAME, whereas pretreatment with indomethacin and glibenclamide reduced the relaxation to a minor extent. Rosmarinic acid was also tested in the same manner as the extract and was found to exert vasorelaxant effect. These results suggest that the aqueous extract of MOO vasodilates via nitric oxide pathway with the possible involvement of prostacycline and endothelium-derived hyperpolarizing factor (EDHF) pathways as well.

Effects of platelet-activating factor antagonists WEB 2086 and BN 50730 on digoxin-induced arrhythmias.

Effects of platelet-activating receptor antagonists WEB 2086 (1.0-30.0 mg.kg-1 intravenously) and BN 50730 (10.0 mg.kg-1 intravenously) alone or in combination with CGS 8515 (a specific 5-lipoxygenase inhibitor, 0.3 mg.kg-1 intravenously) and Dazmegrel (a thromboxane synthase inhibitor, 1.0 mg.kg-1.hr-1 intravenous infusion) on digoxin-induced arrhythmias were investigated in anaesthetised guinea-pigs. ECG, mean arterial blood pressure, heart rate and arrhythmias were recorded, starting 30 min. before digoxin administration and continuing for 60 min. afterwards. WEB 2086 (10.0 mg.kg-1 intravenously) reduced the mortality rate and arrhythmia score significantly compared to the control values. However, in combination with CGS 8515, it did not affect the mortality rate. BN 50730 (10.0 mg.kg-1) reduced the incidence of ventricular fibrillation and also arrhythmia score. BN 50730 in combination with Dazmegrel was reduced the arrhythmia score, incidence of ventricular fibrillation and mortality rate significantly, compared to control values. Digoxin-induced acute rise in mean arterial blood pressure was not affected by any of drug treatment except WEB 2086 (10.0 mg.kg-1) in combination with CGS 8515. Heart rate values did not differ between groups. However, pressure-rate index was reduced by WEB 2086 alone or in combination with CGS 8615. Results showed that although two different platelet-activating factor antagonists have different effects on the incidence of ventricular fibrillation and mortality, they improved the digoxin-induced arrhythmias when they were used either separately or in combination with CGS 8515 or Dazmegrel by implicating that platelet-activating factor has a role on digoxin-induced arrhythmias.

Effects of cyclooxygenase and lipoxygenase inhibitors on digoxin-induced arrhythmias and haemodynamics in guinea-pigs.

Effects of cyclooxygenase and lipoxygenase inhibitors of digoxin-induced arrhythmias and haemodynamics were studied in guinea-pigs. ECG, mean arterial blood pressure heart rate, pressure rate index and arrhythmias were recorded, starting 15 min before digoxin administration and continuing for 30 min afterwards. The cyclooxygenase inhibitor aspirin (50 mg kg-1) and the dual cyclooxygenase/lipoxygenase inhibitor BW 755C (0.25-10.0 mg kg-1) were found to produce a significant protection against the arrhythmias, whereas aspirin (100 mg kg-1) and CGS 8515 were found to be ineffective. SK&F 104 353, a potent and selective peptidoleukotriene receptor antagonist significantly attenuated the arrhythmias and mortality in a dose-dependent manner. It is concluded that production of both cyclooxygenase and lipoxygenase metabolites could favour the occurrence and/or the maintenance of digoxin-induced cardiac toxicity.