Growth interferences between bacterial strains from raw cow's milk and their impact on growth of Listeria monocytogenes and Staphylococcus aureus.

AIMS: The purpose of this study was to detect growth enhancing or inhibiting activity between bacterial populations from raw milk under different conditions (temperature, medium). METHODS AND RESULTS: The interference of 24 raw milk isolates on growth of each other and on Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis and Micrococcus luteus was screened by drop assay and for selected pairs in co-cultivation experiments. By drop assay, antibacterial activity was observed for 40% of the strains. About 30% of the strains showed growth-enhancing activity on other strains. Most of the isolates were well adapted to cold temperatures and showed consistent or even increased inhibiting or enhancing effects on growth of other strains at 10°C. The growth of L. monocytogenes DSM 20600T and S. aureus DSM 1104T was significantly (P < 0·05) reduced in co-cultivation with Pseudomonas protegens JZ R-192. CONCLUSIONS: Growth interferences between bacterial populations have an impact on the structure of raw milk microbiota, especially when it develops under cold storage, and it may have an effect on the prevalence of certain foodborne pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates growth-inhibiting and also growth-enhancing interactions between raw milk bacteria, which must be considered when predicting bacterial growth and spoilage in food. A Ps. protegens strain isolated from raw milk showed an antagonistic effect on growth of L. monocytogenes in refrigerated raw milk.

[Diagnosis of and therapy for choroidal melanoma]. / Diagnostik und Therapie choroidaler Melanome.

BACKGROUND: Prognosis evaluation of patients with choroidal and ciliary melanoma has experienced recent progress through tumour sampling and cytogenetic analysis of metastatic risk. By allocating tumor extension, height and linear basal diameter to defined TNM stages, an estimation of prognosis can also be made without invasive tissue sampling. METHODS: Therapeutic strategies of organ preserving irradiation using different sources have clearly come to the forefront. RESULTS: Due to microscopic haematogenous spreading of tumour cells prior to treatment, the metastatic risk following radiation of any form is not influenced in comparison to primary enucleation. CONCLUSION: However, metastatic disease still remains a fatal condition which currently may only be influenced by early detection and treatment of uveal melanomas.

Bilateral Bartonella henselae neuroretinitis with stellate maculopathy in a 6-year-old boy.

PURPOSE: Bartonella henselae, the cause of cat-scratch disease in humans, may lead to characteristic vision-threatening ocular findings, which importantly indicate diagnosis. METHODS: This is an observational case report of a 6-year-old boy who presented with bilateral stellate maculopathy and lymphadenopathy. RESULTS: After serologic verification of B. henselae infection, systemic azithromycin therapy initiated the full recovery of visual acuity and bilateral complete resolution of stellate exudates during the following months. CONCLUSION: Stellate maculopathy should always include the differential diagnosis of B. henselae infection. In this rare case of bilateral stellate maculopathy, we observed full recovery of function following systemic macrolide therapy.

Course of pattern-reversed visual evoked cortical potentials in 30 eyes after bony orbital decompression in dysthyroid optic neuropathy.

AIM: To investigate optic nerve function using the pattern-reversed visual evoked cortical potentials (VECP) before and after bony orbital decompression in dysthyroid optic neuropathy (DON) due to Graves' disease. METHODS: A total of 30 eyes of 15 patients (n=14 female) were observed over 30 ± 13 months after bony three-wall orbital decompression. We examined visual acuity (VA), VECP P100 amplitudes and latencies, as well as proptosis using Hertel's exophthalmometry. RESULTS: Mean logarithm of the minimum angle of resolution (logMAR) VA increased, statistically significantly, by 2.4 lines during 30 ± 13 months (from 0.38 ± 0.25 before surgery to 0.14 ± 0.1 at the end of observation, p=0.0001). All eyes maintained or improved vision by at least one line. Mean postoperative reduction of proptosis was 6.4 ± 3 mm. While VECP P100 amplitudes improved significantly, P100 latencies remained abnormal in 18 eyes (60%) during follow-up of 10 ± 7 months. Nine eyes (30%) with previous latency defects improved in at least one check test, five of which normalised completely. Worsening was evident in seven eyes (23%), and three previously normal eyes developed new pathological latencies. P100 latencies in 14 eyes (47%) remained unchanged. CONCLUSION: After decompression surgery, DON remission was observed in all patients regarding vision and VECP amplitudes. New or persistent P100 latency defects were seen in 60% of eyes after surgery. DON is considered to be caused by compressive ischaemic damage, which further underlines the importance of early decompression surgery.

Photodynamic therapy with verteporfin in paediatric and young adult patients: long-term treatment results of choroidal neovascularisations.

BACKGROUND: Vision impairment in children and young adults may derive from choroidal neovascularisation (CNV) related to numerous conditions. The aim of this study is to highlight the applicability of photodynamic therapy using verteporfin (PDT) in these patients. METHODS: In 16 eyes of 16 consecutive patients aged 30 years or younger, prospective open-label PDT was performed. Outcomes of visual acuity as well as changes in CNV lesion parameters were evaluated. RESULTS: The mean patient age at first PDT was 19.7 (SD 8.7) years (range 6-30). 81% of the patients retained stable vision within two lines or exceedingly improved vision during follow-up of 34 (24) months. Significant vision gain was denoted in seven paediatric patients (2.7 (1.4) lines, mean (SD); p = 0.019) as well as in a subgroup of 12 patients not affected by active uveitis (2.6 (2.0) lines, p = 0.0005). Two patients with multifocal choroiditis and panuveitis (MCP) experienced vision losses of five and 11 lines after four PDT sessions despite receiving additional steroidal treatment. Except for one patient with MCP and two patients who dismissed follow-up, a mean of 2.2 (1.3) PDTs per patient sufficiently inactivated CNV lesions during follow-up. In the area of the former PDT spot, alterations of the pigment epithelium increased by 40% without correlation to changes in vision. CONCLUSIONS: The results indicate good PDT efficacy and tolerability most promising in a subgroup of patients with vision-impairing CNV not associated with active uveitis. PDT in young patients with CNV remains a valuable treatment with good risk-benefit profile over the long term.

Diversity and antimicrobial susceptibility of oxytetracycline-resistant isolates of Stenotrophomonas sp. and Serratia sp. associated with Costa Rican crops.

AIMS: To ameliorate the identification, evaluate the diversity, and determine the antimicrobial sensitivity of 19 oxytetracycline-resistant isolates of Stenotrophomonas sp. and Serratia sp. associated with Costa Rican crops. METHODS AND RESULTS: Phenotypical, chemotaxonomical, and molecular data allocated most isolates to the species Sten. maltophilia and Ser. marcescens. The API profiles, antimicrobial resistance patterns (ATB system), and BOX-polymerase chain reaction (PCR) genomic fingerprints of isolates of Stenotrophomonas sp. exhibited a higher degree of heterogeneity than those obtained for the isolates of Serratia sp. The former group of bacteria exhibited multiresistance to antimicrobials. In contrast, isolates of Serratia sp. were sensitive to the majority of the drugs tested. Changes in the results of the antibiograms throughout incubation, which indicate an induction of tolerance, were observed for isolates of both the species. Minimum inhibitory concentration of oxytetracycline, determined using E-test stripes, were rather elevated. CONCLUSIONS: The occurrence of two species of opportunistic pathogens in crop-associated materials poses a risk to consumers in the community. SIGNIFICANCE AND IMPACT OF THE STUDY: The phenotypic and genotypic data presented could support epidemiologist and physicians dealing with infections caused by environmental strains of these taxa.

Fatty acid analysis and spoilage potential of biofilms from two breweries.

AIM: The microbial composition of biofilms from different locations of beer bottling plants were compared based on fatty acid profiles and correlated with the product-spoiling potential of these biofilms. METHODS AND RESULTS: The whole cell fatty acid profiles of 78 biofilms from bottling plants of two breweries were analysed. About half of the lipid profiles were dominated by oleic and linoleic acid, which refer to a high proportion of yeasts. In addition, more than half of all samples contained dimethylacetals indicating the presence of strictly anaerobic bacteria. Typical fatty acids for potentially beer-spoiling genera were detected in three biofilms. The majority of the biofilms contained no beer-spoiling organisms, as shown by inoculation experiments in beer. CONCLUSIONS: Biofilms from different locations of bottling plants were different with respect to their microbial composition. Potentially product-spoiling populations could be detected in a small number of samples. SIGNIFICANCE AND IMPACT OF THE STUDY: Biofilms on industrial plants can be characterized by a fast and cultivation-independent method with respect to overall microbial composition and presence of potentially product-spoiling micro-organisms.

Stable-isotope-based labeling of styrene-degrading microorganisms in biofilters.

Deuterated styrene ([(2)H(8)]styrene) was used as a tracer in combination with phospholipid fatty acid (PLFA) analysis for characterization of styrene-degrading microbial populations of biofilters used for treatment of waste gases. Deuterated fatty acids were detected and quantified by gas chromatography-mass spectrometry. The method was evaluated with pure cultures of styrene-degrading bacteria and defined mixed cultures of styrene degraders and non-styrene-degrading organisms. Incubation of styrene degraders for 3 days with [(2)H(8)]styrene led to fatty acids consisting of up to 90% deuterated molecules. Mixed-culture experiments showed that specific labeling of styrene-degrading strains and only weak labeling of fatty acids of non-styrene-degrading organisms occurred after incubation with [(2)H(8)]styrene for up to 7 days. Analysis of actively degrading filter material from an experimental biofilter and a full-scale biofilter by this method showed that there were differences in the patterns of labeled fatty acids. For the experimental biofilter the fatty acids with largest amounts of labeled molecules were palmitic acid (16:0), 9,10-methylenehexadecanoic acid (17:0 cyclo9-10), and vaccenic acid (18:1 cis11). These lipid markers indicated that styrene was degraded by organisms with a Pseudomonas-like fatty acid profile. In contrast, the most intensively labeled fatty acids of the full-scale biofilter sample were palmitic acid and cis-11-hexadecenoic acid (16:1 cis11), indicating that an unknown styrene-degrading taxon was present. Iso-, anteiso-, and 10-methyl-branched fatty acids showed no or weak labeling. Therefore, we found no indication that styrene was degraded by organisms with methyl-branched fatty fatty acids, such as Xanthomonas, Bacillus, Streptomyces, or Gordonia spp.

Application of rRNA-targeted oligonucleotide probes in biotechnology.

Ribosomal RNA-targeted oligonucleotide probes have become valuable tools for the detection of microorganisms involved in important biotechnological processes. Microorganisms which are of major importance for processes such as wastewater treatment, microbial leaching or methane production can be detected and quantified in situ within a complex microbial community. For certain processes, such as nitrification or biological phosphate removal, new microorganisms have become the focus of interest and have led to an improved understanding of these bioremediation techniques. Hybridization techniques have become fast and reliable alternatives to conventional cultivation techniques in the food industry as a control method for starter cultures for fermentation processes or product control. Recent analytical tools such as flow cytometry and digital image processing have improved the efficiency of these techniques. This review is intended to present a summary of methodological aspects of rRNA-based hybridization techniques and their application in biotechnology.

Fatty acid profiles of nitrite-oxidizing bacteria reflect their phylogenetic heterogeneity.

The fatty acid profiles of all described species of the nitrite-oxidizing genera Nitrobacter, Nitrococcus, Nitrospina and Nitrospira were analyzed. The four genera had distinct profiles, which can be used for the differentiation and allocation of new isolates to these genera. The genus Nitrobacter is characterized by vaccenic acid as the main compound with up to 92% of the fatty acids and the absence of hydroxy fatty acids. The genus Nitrococcus showed cis-9-hexadecenoic acid, hexadecanoic acid and vaccenic acid as main parts. Small amounts of 3-hydroxy-dodecanoic acid were detected. The genus Nitrospina possessed tetradecanoic acid and cis-9-hcxadecenoic acid as main compounds, also 3-hydroxy-hexadecanoic acid was detected for this genus. The genus Nitrospira showed a pattern with more variations among the two described species. These organisms are characterized by the cis-7 and cis-11-isomers of hexadecenoic acid. For Nitrospira moscoviensis a specific new fatty acid was found, which represented the major constituent in the fatty acid profiles of autotrophically grown cultures. It was identified as 11-methyl-hexadecanoic acid. Since this compound is not known for other bacterial taxa, it represents a potential lipid marker for the detection of Nitrospira moscoviensis relatives in enrichment cultures and environmental samples. A cluster analysis of the fatty acid profiles is in accordance with 16S rRNA sequence-based phylogeny of the nitrite-oxidizing bacteria.

Physical properties of liposomes and proteoliposomes prepared from Escherichia coli polar lipids.

Reconstituted proteoliposomes serve as experimental systems for the study of membrane enzymes. Osmotic shifts and other changes in the solution environment may influence the structures and membrane properties of phospholipid vesicles (including liposomes, proteoliposomes and biological membrane vesicles) and hence the activities of membrane-associated proteins. Polar lipid extracts from Escherichia coli are commonly used in membrane protein reconstitution. The solution environment influenced the phase transition temperature and the diameter of liposomes and proteoliposomes prepared from E. coli polar lipid by extrusion. Liposomes prepared from E. coli polar lipids differed from dioleoylphosphatidylglycerol liposomes in Young's elastic modulus, yield point for solute leakage and structural response to osmotic shifts, the latter indicated by static light scattering spectroscopy. At high concentrations, NaCl caused aggregation of E. coli lipid liposomes that precluded detailed interpretation of light scattering data. Proteoliposomes and liposomes prepared from E. coli polar lipids were similar in size, yield point for solute leakage and structural response to osmotic shifts imposed with sucrose as osmolyte. These results will facilitate studies of bacterial enzymes implicated in osmosensing and of other enzymes that are reconstituted in E. coli lipid vesicles.

Characterization of N2O-producing Xanthomonas-like isolates from biofilters as Stenotrophomonas nitritireducens sp. nov., Luteimonas mephitis gen. nov., sp. nov. and Pseudoxanthomonas broegbernensis gen. nov., sp. nov.

A group of yellow-pigmented isolates from ammonia-supplied biofilters showed an unusual denitrification reaction. All strains reduced nitrite but not nitrate without production of nitrogen (N2). The only product found was nitrous oxide (N2O). The strains were divided into two clusters and one separate strain by their fatty acid profiles, which were similar to the fatty acid profiles of the genera Xanthomonas and Stenotrophomonas. Analyses of the 165 rDNA sequences showed that these clusters and the separate strain form three independent lines within the Xanthomonas branch of the Proteobacteria. The evolutionary distances of the isolates to members of the related genera Xanthomonas, Stenotrophomonas and Xylella calculated by the 16S rDNA sequences led to the proposal of two new genera and three new species, Stenotrophomonas nitritireducens sp. nov., Luteimonas mephitis gen. nov., sp. nov. and Pseudoxanthomonas broegbernensis gen. nov., sp. nov. The type strains are Stenotrophomonas nitritireducens L2T (= DSM 12575T), Luteimonas mephitis B1953/27.1T (= DSM 12574T) and Pseudoxanthomonas broegbernensis B1616/1T (= DSM 12573T).

DNA methyltransferase contributes to delayed ischemic brain injury.

DNA methylation is important for controlling the profile of gene expression and is catalyzed by DNA methyltransferase (MTase), an enzyme that is abundant in brain. Because significant DNA damage and alterations in gene expression develop as a consequence of cerebral ischemia, we measured MTase activity in vitro and DNA methylation in vivo after mild focal brain ischemia. After 30 min middle cerebral artery occlusion (MCAo) and reperfusion, MTase catalytic activity and the 190 kDa band on immunoblot did not change over time. However, [(3)H]methyl-group incorporation into DNA increased significantly in wild-type mice after reperfusion, but not in mutant mice heterozygous for a DNA methyltransferase gene deletion (Dnmt(S/+)). Dnmt(S/+) mice were resistant to mild ischemic damage, suggesting that increased DNA methylation is associated with augmented brain injury after MCA occlusion. Consistent with this formulation, treatment with the MTase inhibitor 5-aza-2'-deoxycytidine and the deacetylation inhibitor trichostatin A conferred stroke protection in wild-type mice. In contrast to mild stroke, however, DNA methylation was not enhanced, and reduced dnmt gene expression was not protective in an ischemia model of excitotoxic/necrotic cell death. In conclusion, our results demonstrate that MTase activity contributes to poor tissue outcome after mild ischemic brain injury.

Community analysis of biofilters using fluorescence in situ hybridization including a new probe for the Xanthomonas branch of the class Proteobacteria.

Domain-, class-, and subclass-specific rRNA-targeted probes were applied to investigate the microbial communities of three industrial and three laboratory-scale biofilters. The set of probes also included a new probe (named XAN818) specific for the Xanthomonas branch of the class Proteobacteria; this probe is described in this study. The members of the Xanthomonas branch do not hybridize with previously developed rRNA-targeted oligonucleotide probes for the alpha-, beta-, and gamma-Proteobacteria. Bacteria of the Xanthomonas branch accounted for up to 4.5% of total direct counts obtained with 4',6-diamidino-2-phenylindole. In biofilter samples, the relative abundance of these bacteria was similar to that of the gamma-Proteobacteria. Actinobacteria (gram-positive bacteria with a high G+C DNA content) and alpha-Proteobacteria were the most dominant groups. Detection rates obtained with probe EUB338 varied between about 40 and 70%. For samples with high contents of gram-positive bacteria, these percentages were substantially improved when the calculations were corrected for the reduced permeability of gram-positive bacteria when formaldehyde was used as a fixative. The set of applied bacterial class- and subclass-specific probes yielded, on average, 58.5% (+/- a standard deviation of 23.0%) of the corrected eubacterial detection rates, thus indicating the necessity of additional probes for studies of biofilter communities. The Xanthomonas-specific probe presented here may serve as an efficient tool for identifying potential phytopathogens. In situ hybridization proved to be a practical tool for microbiological studies of biofiltration systems.

Characterization of microbial communities of biofilters by phospholipid fatty acid analysis and rRNA targeted oligonucleotide probes.

The microbial community of a biofilter for waste gas treatment of an animal rendering plant was characterized by the analyses of the phospholipid fatty acids (PLFAs) of the filter material. For these analyses five samples of one filter were taken in intervals between one and two months. The main components of the PLFA profiles were straight chain saturated, monounsaturated and cyclopropyl fatty acids. Terminally branched and 10-methyl branched fatty acids were present in minor amounts. The structure and succession of the microbial community was interpreted by the presence and quantitative changes of diagnostic fatty acids. The stability of diagnostic fatty acids in relation to varying incubation parameters was tested for a number of bacterial isolates from biofilters representing different phylogenetic branches. For two samples, the data from the PLFA-analyses were compared with data obtained by hybridization with fluorescently labeled, rRNA-targeted oligonucleotide probes specific for the alpha-, beta- and gamma-subclass of the Proteobacteria, the Actinobacteria (Firmicutes with high G+C content) and the Firmicutes with low G+C content. These data indicated a dominating number of Proteobacteria (54% and 35% of DAPI-stained cells), in which the gamma-Proteobacteria represented the main fraction. Actinobacteria were detected in minor amounts, the number of Firmicutes with low G+C content was near the detection limit of the method. About half of the cells detected with a probe specific for Bacteria did not hybridize with the probes specific for the alpha-, beta- and gamma subclass of the Proteobacteria and the two subgroups of the Firmicutes. The results of both methods, the fluorescence in situ hybridization (FISH) and the PLFA analyses corresponded well and were best suited to confirm and complement each other.

Pseudonocardia asaccharolytica sp. nov. and Pseudonocardia sulfidoxydans sp. nov., two new dimethyl disulfide-degrading actinomycetes and emended description of the genus Pseudonocardia.

Seven bacterial strains capable of oxidizing methyl sulfides were isolated from experimental biofilters filled with tree-bark compost. The isolates could be divided into two groups according to their method of methyl sulfide degradation. Four isolates could use only dimethyl disulfide as the sole source of energy and three strains were able to use dimethyl sulfide and dimethyl disulfide. Oxidation of the methyl sulfides by both groups led to the stoichiometric formation of sulfate. Chemotaxonomic, morphological, physiological and phylogenetic properties identified all isolates as members of the genus Pseudonocardia. The absence of phosphatidylcholine from the polar lipid pattern, as well as results of 16S rDNA analyses, led to the proposal of two new species, Pseudonocardia asaccharolytica sp. nov. and Pseudonocardia sulfidoxydans sp. nov. The type strains are P. asaccharolytica DSM 44247T and P. sulfidoxydans DSM 44248T. With respect to the characteristic polar lipid pattern and the ability to oxidize sulfides, an emended description of the genus Pseudonocardia is proposed.

Identification of bacterial isolates from biofilters as Paracoccus alkenifer sp. nov. and Paracoccus solventivorans with emended description of Paracoccus solventivorans.

Two groups of strains isolated from biofilters for the treatment of waste gases were assigned to the genus Paracoccus by phylogenetic and chemotaxonomic methods. All type strains of the genus Paracoccus were compared with these groups using 16S rDNA sequence analysis, fatty acid patterns and physiological reaction profiles. For both groups, the nearest related reference species was Paracoccus solventivorans based on 16S rDNA sequence similarity. However, whereas one group of isolates was identified as a member of this species by fatty acid analysis and DNA-DNA hybridization, the other group was proposed as a new species, Paracoccus alkenifer sp. nov. Fatty acid analysis showed the unusual fatty acid 20:1cis13 instead of 19:0 cyclo11-12 for P. alkenifer and P. solventivorans, and 14:1cis7 instead of 12:1cis5 for P. alkenifer and Paracoccus kocurii. By means of a GC-MS method, diaminopimelic acid was detected for P. solventivorans. Based on these results we propose an emended description for the species P. solventivorans.

Nature of pulmonary hypertension in congestive heart failure. Effects of cardiac transplantation.

Pulmonary hypertension associated with congestive heart failure carries a risk of right ventricular failure after cardiac transplantation. Few data, however, are available on the hemodynamic behavior of the pulmonary circulation in these patients. We therefore studied mean pulmonary artery pressure minus left atrial pressure (estimated by pulmonary artery occluded pressure) versus cardiac output relationships in 20 patients with congestive heart failure evaluated for orthotopic cardiac transplantation, and we repeated this study either within the first 3 days postoperatively (n = 10) or 1 month postoperatively (n = 11). Cardiac output was increased by physical exercise or (in the early postoperative period) by an infusion of dobutamine. Reversibility of pulmonary hypertension was tested by an infusion of prostaglandin E1. At preoperative evaluation, the extrapolated pressure intercept of pulmonary vascular pressure:flow plots was negative in 10 of the patients, suggesting active exercise-induced pulmonary vasoconstriction. In the other 10 patients, the extrapolated pressure intercept was positive, suggesting that an increased closing pressure contributed to pulmonary hypertension. However, transplantation was constantly associated with proportional decreases of pulmonary artery pressure and left atrial pressure. On the other hand, pulmonary vascular pressure:flow plots were displaced to equal or lower pressures and to higher flows by prostaglandin E1 before as well as after transplantation. We conclude that in patients with congestive heart failure evaluated for cardiac transplantation, an increased pulmonary venous pressure more than a reversible increase in closing pressure determines the severity of pulmonary hypertension.

Acute myocardial infarction immediately after heart transplantation.

Myocardial infarction is one of the rarer events causing acute graft failure during the postoperative period after transplantation and is usually caused by preexisting coronary artery disease of the donor heart. We discuss the case of a 56-year-old man in whom cardiogenic shock developed after heart transplantation, which was refractory to all medical treatment. He was put on emergency code and underwent retransplantation 30 hours later. Pathologic examination of the explanted donor heart showed massive recent inferior and posterior wall infarction, with normal coronary arteries; the right coronary artery was dominant and completely occluded by an embolus of fatty material surrounded by fibrin, which we suggest could have originated from the suture line of the left atrium.

Radiation-induced pulmonary veno-occlusive disease.

Late occurrence of radiation-induced pulmonary pneumonitis and fibrosis is well documented. We report an unusual case of radiation induced veno-occlusive disease (VOD) occurring six years following mantle irradiation for Hodgkin's lymphoma. The patient developed severe pulmonary hypertension and cor pulmonale. A left lung transplantation was performed successfully and pathologic examination of the explanted lung showed severe changes compatible with VOD. In the absence of exposure to alternate therapeutic or toxic agents that may cause VOD, it is likely that radiation caused damage to the venular endothelium and caused progressive obliteration of the pulmonary vessels. Review of the literature reveals only a few similar reports of VOD mostly following radiation for bone marrow transplantation. We conclude that previous irradiation (even several years earlier) should be considered as a possible cause of pulmonary VOD.