Unusual microbes in asthma exacerbation: Alcaligenes xylosoxidans and Leishmania.

Asthma is a chronic inflammatory condition characterised by a variable degree of airflow limitation. Exacerbations during the course of asthma often occur due to environmental factors or infectious, mostly viral, aetiology. The present study reports the case of a 61-yr-old male with severe asthma hospitalised due to increasing respiratory distress. Since recovery was delayed despite anti-obstructive/anti-inflammatory and antibiotic therapy, further diagnostic procedures, including bronchoscopy, were performed in order to attempt to identify the cause of the worsening respiratory condition. The surprising finding consisted of a rare coincidence of concomitant infection with the bacterial pathogen Alcaligenes xylosoxidans, grown from bronchoalveolar lavage fluid, and the protozoan parasite Leishmania spp., revealed by histopathological examination of bronchial mucosal biopsy specimens. This is the first report of an isolated bronchial mucosal involvement of Leishmania in an HIV-negative asthma patient following brief exposure in Leishmania-endemic regions. Further, to the best of the present authors' knowledge, this represents the first description of A. xylosoxidans in asthma, although it is questionable whether it was an infection or colonisation. The present observation identifies previously unreported microbial pathogens associated with asthma exacerbation. Further, the report highlights the importance of obtaining a thorough travel history and applying invasive diagnostic procedures in circumstances of treatment failure, even under unfavourable conditions.

Endocytosis in different lifestyles of protozoan parasitism: role in nutrient uptake with special reference to Toxoplasma gondii.

A fundamental property of any eukaryotic cell is endocytosis, that is the ability to take up external fluid, solutes and particulate matter into membrane-bound intracellular vesicles by various mechanisms. Toxoplasma gondii is an intracellular protozoan parasite of the phylum Apicomplexa with a wide geographical and host range distribution. Significant progress in studying the cell biology of this parasite has been accomplished over the last few years. Only recently endocytic compartments and endocytic trafficking have come to a closer dissection in T. gondii. In this review, we discuss the evidence for an endocytic compartment and present a model for an endocytic pathway in Toxoplasma against a background of endocytosis in kinetoplastida and the extensive insights gained from mammalian and yeast cells.

Endothelial cell compatibility of clarithromycin for intravenous use.

OBJECTIVES: Tolerance of intravenously applied clarithromycin has been tested on marginal ear veins of rabbits. Use of human umbilical venous endothelial cells (HUVEC) for testing antibiotic solutions for intravenous compatibility provides a valuable alternate model. DESIGN AND METHODS: In order to evaluate the effect of clarithromycin on intracellular purines, reflecting cell viability, energy production, signal transduction and DNA/RNA synthesis, intracellular adenosine 5' triphosphate (ATP), adenosine 5' diphosphate (ADP), guanosine 5' triphosphate (GTP), and guanosine 5' diphosphate (GDP) levels were measured by means of high performance liquid chromatography (HPLC). RESULTS: Incubation of cells with 2 mg/mL clarithromycin resulted in a rapid decrease of the intracellular ATP from 12.6 +/- 1.1 to 8.87 +/- 0.82 nmol/million cells or 1.5 +/- 0.6 nmol/million cells, after 20 or 60 min, respectively. In addition, ADP was extensively depleted. Purine nucleotide profiles were markedly different following exposure to 1 mg/mL clarithromycin. There was no significant decline of intracellular high energy phosphate levels after 20 min. CONCLUSION: These results show that clarithromycin has a better endothelial compatibility if diluted to a final concentration of 1 mg/mL. These data are in line with our clinical observations that the occurrence of phlebitis could be minimized by diluting the manufacturers' preparation of clarithromycin to 1 mg/mL.

Effects of imipenem and meropenem on purine content of endothelial cells.

UNLABELLED: Intravenous compatibility of antibacterial agents has been tested in animal models. Use of human umbilical venous endothelial cells (HUVEC) to test antibiotic solutions for intravenous tolerance provides a valuable alternate model. OBJECTIVE: Evaluation of the effect of imipenem and meropenem on intracellular purines reflecting viability, energy production, signal transduction, and DNA/RNA synthesis of these cells. MATERIALS AND METHODS: Levels of intracellular adenosine 5' triphosphate (ATP), adenosine 5' diphosphate (ADP), guanosine 5' triphosphate (GTP) and guanosine 5' diphosphate (GDP) were measured by means of high performance liquid chromatography (HPLC). RESULTS: The total amount of ATP after incubation of cells with 10.0 mg/ml imipenem and meropenem for 20 minutes (12.93 +/- 0.93 nmol/million cells and 13.27 +/- 0.89 nmol/million cells, respectively) did not result in a decrease compared to controls (12.34 +/- 0.87 nmol/million cells). In addition, ATP levels were maintained or actually increased after 60 minutes. Incubation of cells with 5.0 mg/ml and 2.5 mg/ml of imipenem or meropenem for 20 and 60 minutes showed similar results. Purine nucleotide profiles of ADP, GTP, GDP following exposure of 10.0 mg/ml, 5.0 mg/ml and 2.5 mg/ml of imipenem and meropenem did not differ markedly. CONCLUSIONS: These in vitro data show an excellent endothelial compatibility of imipenem and meropenem even in high concentrations.

Endothelial cell compatibility of fluoroquinolone solutions for intravenous use.

One local side-effect closely related to the use of parenteral fluoroquinolones is phlebitis. The occurrence of this phenomenon is largely thought due to the damage of endothelial cells with subsequent inflammation. In order to evaluate the effect of ciprofloxacin, fleroxacin, and ofloxacin on the viability of human umbilical venous endothelial cells (HUVEC), intracellular ATP levels were measured by a luciferin-luciferase assay. Prostacyclin (PGI2) and thromboxane A2 (TXA2) were determined by means of direct radioimmunoassay. Commercially available preparations of ciprofloxacin (2 mg/ml) and fleroxacin (4 mg/ml) reduced the intracellular ATP content by 75.9 +/- 1.9% and 82.1 +/- 0.6%, respectively, within 20 minutes, indicating severe damage of endothelial cells. Incubation with ofloxacin (2 mg/ml) did not have any detrimental effect. All fluoroquinolones were tolerated well by endothelial cells at low concentrations up to 20 micrograms/ml. Concentrations between 100-200 micrograms/ml gradually led to functional alterations such as increased PGI2 release. The tolerance of intravenously applied antibiotics has been tested in animal models. Use of human venous endothelial cells for testing antibiotic solutions for intravenous application provides a valuable alternate model for tolerability.

Influence of glycopeptide antibiotics on purine metabolism of endothelial cells.

We provide evidence that the commercially available preparations of glycopeptides for intravenous application are well tolerated by endothelial cells when applied in concentrations less than 5 mg/ml. Since the antibiotics tested are administered at maximal concentrations of 10 mg/ml, the dose range used in our in vitro experiments (5 and 10 mg/ml) mimics possible clinical concentrations at the site of infusion. Similar concentrations may be reached by retrograde intravenous pressure infusion techniques (10-12). We have demonstrated that these high concentrations lead to considerable endothelial cell damage. These findings may explain the common side effect associated with intravenously applied glycopeptides namely pain and phlebitis at the site of infusion (2, 13). Figure 1 shows that a detrimental effect measurable after 20 min occurs only using vancomycin solutions at concentrations of 10 mg/ml, whereas already a dilution to 5 mg/ml renders the solutions more compatible to HUVEC. These data are in line with the observation that slow intravenous application of glycopeptides into large veins can largely prevent the occurrence of local phlebitis. Alternatively, the occurrence of phlebitis should be avoidable by diluting the manufacturers' preparations at least to 2-5 mg/ml and not 10 mg/ml as recommended by the manufacturer of vancomycin. The same aspects need to be considered for use of glycopeptides for retrograde high pressure infusion. The tolerance of intravenously applied antibiotics has previously been tested in animal models (4). Our model of human venous endothelial cells for testing antibiotic solutions for intravenous compatibility provides a valuable alternate model. In conclusion our data show that the commercial preparation of teicoplanin is more compatible for HUVEC than those of vancomycin.

[Mucormycosis--a rare complication in patients with diabetes mellitus]. / Mucormykose--Eine seltene Komplikation bei Patienten mit Diabetes mellitus.

Mucormycosis usually occurs in immunocompromised patients or in patients with diabetes mellitus. Pathogens are moulds of the mucorales species. The diagnosis is made by histological examination of biopsies. A 39 year-old patient with insulin-dependent diabetes mellitus was admitted with a tentative diagnosis of a tumour of the maxilla. After diagnosis of hyphae of the mucorales species, the patient's diabetes was stabilised and he was treated over 17 weeks with amphotericin B (40 mg per day) and made a good recovery. A 58 year-old insulin-dependent patient with ethmoidali and sphenoidali sinusitis did not respond to antibiotic therapy. Mucormycosis was diagnosed by means of biopsy. Although treatment with amphotericin B was started, the patient died after 3 weeks due to multiple organ failure.

Endothelial cell compatibility of trovafloxacin and levofloxacin for intravenous use.

Levofloxacin and trovafloxacin have excellent activity against a variety of Gram-positive and Gram-negative organisms resistant to the established agents. One local side-effect closely related to the use of parenteral fluoroquinolones is phlebitis. To evaluate the effect of trovafloxacin and levofloxacin on endothelial cell viability, intracellular levels of adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), guanosine 5'-triphosphate (GTP) and guanosine 5'-diphosphate (GDP) levels were measured using high-performance liquid chromatography. Trovafloxacin at concentrations of 2 and 1 mg/mL reduced the intracellular ATP content from 12.5 +/- 1.7 to 1.9 +/- 0.3 nmol/10(6) cells and 9.3 +/- 0.8 nmol/10(6) cells, respectively, within 60 min. In addition, ADP, GTP and GDP levels were extensively depleted. Levofloxacin at concentrations of 5 and 2.5 mg/mL led to a significant ATP decline from 12.5 +/- 1.7 to 2.3 +/- 0.2 nmol/10(6) cells and 10.3 +/- 0.9 nmol/10(6) cells, respectively, within 60 min. These data indicate that infusions of high doses of trovafloxacin or levofloxacin are not compatible with maintenance of endothelial cell function. Commercial preparations have to be diluted and should be administered into large veins.

Endothelial cell compatibility of glycopeptide antibiotics for intravenous use.

The use of human venous endothelial cells for testing antibiotic solutions for intravenous compatibility provides a valuable alternative to animal models. In order to evaluate the effect of vancomycin and teicoplanin on the viability of human umbilical venous endothelial cells, intracellular ATP levels were measured by a luciferin-luciferase assay. Prostacyclin (PGI2) and thromboxane A2 (TXA2) were determined by direct radioimmunoassay. Vancomycin at concentrations of 5 and 10 mg/mL reduced the intracellular ATP content by 18.7% and 69.9%, respectively, within 60 min. In contrast, cellular energy charge remained significantly higher after incubation with teicoplanin at 5 and 10 mg/mL (reduction 8.7% and 15.5%, respectively). Neither vancomycin nor teicoplanin at a concentration of 2 mg/mL led to significant ATP decline. However, endothelial cells incubated with vancomycin resulted in significantly lower release of PGI2 and TXA2 compared with teicoplanin. These results show that teicoplanin is more compatible with endothelial cells than vancomycin, and that both antibiotics are well tolerated if diluted to a final concentration of 2 mg/mL.

Endothelial cell compatibility of clindamycin, gentamicin, ceftriaxone and teicoplanin in Bier's arterial arrest.

In patients with infected diabetic foot lesions, and gangrenous, peripheral, occlusive arterial disease, it is important to achieve high concentrations of antibiotics in the tissues, as the extent of amputation is often influenced by the presence of infection. Local transvenous pressure injection of antibiotics, in Bier's arterial arrest, allows high local tissue concentrations to be attained in the extremities. Information on the endothelial compatibility of antibiotics in high concentrations combined with the effect of reperfusion injury following tissue hypoxia is lacking. To evaluate the effect of clindamycin, gentamicin, ceftriaxone and teicoplanin injected in Bier's arterial arrest, on endothelial cells, an in-vitro model using human umbilical venous endothelial cells (HUVEC) has been devised. The intracellular levels of purine nucleotides, reflecting DNA/RNA synthesis, energy production and signal transduction of these cells were measured by means of high-performance liquid chromatography. Incubation of cells with 10 mg/mL clindamycin, gentamicin, ceftriaxone and teicoplanin for 20 min resulted in no significant decline of intracellular purines. Levels of purines obtained after exposure of the cells to 0.1 mmol/L hydrogen peroxide (H2O2), to simulate reperfusion injury, were not significantly different from those obtained from cells allowed to recover after antibiotic exposure. These findings indicate that the infusion of high doses of antibiotics, during Bier's arterial arrest, is compatible with maintenance of endothelial cell function, even in the presence of increased free radical activity, provided the exposure is limited to 20 min.

Endothelial cell compatibility of azithromycin and erythromycin.

Phlebitis is a severe local adverse event related to the use of parenteral macrolides. In order to evaluate the effect of azithromycin and erythromycin on human venous endothelial cells, we set up an in vitro model. The intracellular levels of purine nucleotides, as adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP) and guanosine 5'-triphosphate (GTP), were measured by means of high-performance liquid chromatography. Incubation of cells with 2 mg/mL azithromycin and erythromycin resulted in a rapid decline of intracellular ATP from 12.5 +/- 0.9 nmol/million cells to 4.1 +/- 0.3 and 2.6 +/- 0.4 nmol/million cells, respectively, after 60 min. In addition, ADP was extensively depleted from 2.1 +/- 0.17 nmol/million cells to 0.8 +/- 0.09 and 0.8 +/- 0.13 nmol/million cells after 60 min. After exposure of 0.5 mg/mL azithromycin and erythromycin, no significant decline of intracellular high-energy phosphate levels occurred after 20 and 60 min. Based on these results, solutions of azithromycin and erythromycin may not be well tolerated and may cause local adverse reactions even if diluted according to the manufacturer's recommendation.