Lipopolysaccharide (LPS) from Burkholderia cepacia is more active than LPS from Pseudomonas aeruginosa and Stenotrophomonas maltophilia in stimulating tumor necrosis factor alpha from human monocytes.
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Whole cells and lipopolysaccharides (LPSs) extracted from Burkholderia cepacia, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Escherichia coli were compared in their ability to stimulate tumor necrosis factor alpha (TNF-alpha) from the human monocyte cell line MonoMac-6. B. cepacia LPS, on a weight-for-weight basis, was found to have TNF-alpha-inducing activity similar to that of LPS from E. coli, which was approximately four- and eightfold greater than the activity of LPSs from P. aeruginosa and S. maltophilia, respectively. The LPS-stimulated TNF-alpha production from monocytes was found to be CD14 dependent. These results suggest that B. cepacia LPS might play a role in the pathogenesis of inflammatory lung disease in cystic fibrosis, and in some patients it might be responsible, at least in part, for the sepsis-like cepacia syndrome. (+info)
Xf phage invading the host cells with their protein coats.
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The Xf phage coat protein associated with infected cells could not be removed by washing with antiserum and tris-EDTA buffer. Although the infected cells were consecutively washed 6 times with tris-EDTA buffer, the ratios of parental phage 6H-DNA to 14C-protein were not changed. A considerable amount of the parental 14C-protein and 3H-DNA in the original ratio were detected in the membrane and the soluble cytoplasmic fractions of infected cells. The studies of the change in Xf 14C-protein and 3H-DNA incorporation into the host cells and their release showed that DNA and protein penetrate together into the host cells during the first 60 min after infection (p.i.). While virtually all parental DNA was conserved, re-utilized and released from the infected cell 60 min p.i., no apparent release of parental protein was observed. Approx. 40% of the parental protein became degraded and could be washed from the infected cell after 90 min; the rest of the parental protein remained and probably was re-utilized by the host. (+info)
AFLP fingerprinting: an efficient technique for detecting genetic variation of Xanthomonas axonopodis pv. manihotis.
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Xanthomonas axonopodis pv. manihotis (Xam) is the causative agent of cassava bacterial blight (CBB), a worldwide disease that is particularly destructive in South America and Africa. CBB is controlled essentially through the use of resistant varieties. To develop an appropriate disease management strategy, the genetic diversity of the pathogen's populations must be assessed. Until now, the genetic diversity of Xam was characterized by RFLP analyses using ribotyping, and plasmid and genomic Xam probes. We used AFLP (amplified fragment length polymorphism), a novel PCR-based technique, to characterize the genetic diversity of Colombian Xam isolates. Six Xam strains were tested with 65 AFLP primer combinations to identify the best selective primers. Eight primer combinations were selected according to their reproducibility, number of polymorphic bands and polymorphism detected between Xam strains. Forty-seven Xam strains, originating from different Colombian ecozones, were analysed with the selected combinations. Results obtained with AFLP are consistent with those obtained with RFLP, using plasmid DNA as a probe. Some primer combinations differentiated Xam strains that were not distinguished by RFLP analyses, thus AFLP fingerprinting allowed a better definition of the genetic relationships between Xam strains. (+info)
Removal of cadmium from scallop hepatopancreas by microbial processes.
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A microbial process for removing cadmium from a homogenate of hepatopancreas, a waste of scallop processing, was devised to use this waste for value-added protein resources. Microorganisms were screened on the basis of the ability to remove cadmium from a medium with the initial concentration of 10 mg/l of cadmium. One soil isolate, identified as Xanthomonas sp. UR No. 2 by its taxonomical characteristics, removed 98% of the cadmium in the medium in 2 d. During cultivation of this strain in the homogenates of hepatopancreas digested by endopeptidases, 90% of cadmium was removed, while this strain had little effect on the simple non-digested homogenates. The mass balance of cadmium during homogenizations of the hepatopancreas tissues and cultivations in the protease-treated homogenate were examined. The content of crude proteins of culture supernatant treated by Xanthomonas sp. UR No. 2 was equivalent to those of various feedstuffs on the market. (+info)
Correlation between genotype and beta-lactamases of clinical and environmental strains of Stenotrophomonas maltophilia.
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Heterogeneity of beta-lactamase production by 17 clinical and nine environmental isolates of Stenotrophomonas maltophilia was investigated using MICs of six different beta-lactam antibiotics, isoelectric focusing (IEF) and pulsed field gel electrophoresis. There was no clear correlation between the results of IEF, genotype and MIC determination. Environmental isolates were more susceptible than clinical isolates; eight clinical and none of the environmental isolates expressed high-level resistance to meropenem. Only two isolates expressed high-level resistance to ceftazidime. These results indicate that further studies are required to elucidate the extent of genetic heterogeneity within the L1 and L2 beta-lactamase genes. (+info)
Community analysis of biofilters using fluorescence in situ hybridization including a new probe for the Xanthomonas branch of the class Proteobacteria.
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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. (+info)
Peritonitis due to Stenotrophomonas maltophilia in patients undergoing chronic peritoneal dialysis.
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The occurrence of cases of Stenotrophomonas maltophilia peritonitis in chronic peritoneal dialysis (PD) patients prompted a review of our experience with this condition. A search of microbiology records revealed seven episodes of S. maltophilia peritonitis in 7 patients in 1996 - 3.8% of all PD patients - compared to no cases in 1994 and 1995 (p = 0.01). Patients ranged in age from 16 to 64 years; there were 3 males and 4 females. Six of seven episodes of peritonitis were community acquired and one was hospital acquired. No temporal clustering of cases was seen. Patients were from different urban and rural communities. Patients used the same commercially supplied dialysate fluid, different dialysis techniques, and were taught a no-touch technique for connection. Treatment of peritonitis required removal of the Tenckhoff catheter in 4 of 7 cases. Fingerprinting of six available isolates by polymerase chain reaction using primers derived from the conserved region of the 16/23Sr RNA gene sequence and pulsed field gel electrophoresis revealed all to be unique strains. A case-control study comparing 7 S. maltophilia cases to 21 PD controls showed case patients to be younger and more likely to be on immunosuppressive therapy. We conclude that S. maltophilia has emerged as an important cause of peritonitis in our continuous ambulatory PD population. Evidence to date suggests community acquisition with no evidence of a common source. (+info)
Pseudoaneurysm of the subclavian artery due to Xanthomonas pneumonia in a patient with acute myeloid leukemia: its rupture treated by transcatheter coil embolization.
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A 52-year-old male with acute myeloid leukemia developed pseudoaneurysm of the subclavian artery. Pneumonia due to Xanthomonas maltophilia, which was multi-drug resistant, progressed to a lung abscess even under administration of antibiotics. This lung infection contiguous to the left carotid and subclavian arteries was suggested to have caused the pseudoaneurysm of the subclavian artery. The rupture of the aneurysm by penetration to the trachea amounted to about 1,000 ml of bleeding; fortunately the bleeding ceased spontaneously. Nonetheless, an emergency transcatheter coil embolization prevented re-bleeding. Endovascular treatment should be considered especially for aneurysms which develop in patients with underlying diseases. (+info)