[Differentiation of Pseudomonas aeruginosa compared with Pseudomonas fluorescens & Pseudomonas putida on TTC culture medium].
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The sequence of a 292 bp segment of the DNA encoding 16S rRNA (corresponding to positions 44-337 of the Escherichia coli 16S rRNA sequence) was determined for each of 40 Pseudomonas solanacearum, four banana Blood Disease Bacterium, three P. syzygii and two P. pickettii strains. Phylogenetic relationships derived from comparison of these sequences to each other, and to equivalent 16S rRNA gene sequences from other bacteria present in the EMBL databank, conform well with those obtained previously by DNA-DNA/rRNA hybridization experiments. The 16S rRNA sequence of the Blood Disease Bacterium was identical over the 292 bp to one of the four sequence groups of P. solanacearum, suggesting that these pseudomonads are more closely related to each other than to P. syzygii or P. pickettii. Sequence data comparisons allowed construction of an oligonucleotide specific for P. solanacearum, P. syzygii and the Blood Disease Bacterium. Use of the specific oligonucleotide with a non-specific oligonucleotide in the polymerase chain reaction enabled 1-10 cells of bacteria in this group to be detected after 50 rounds of amplification by visualizing a 287-288 bp product on agarose gels.
Pseudomonas APS selective medium has been developed on the basis of a newly detected selective antibacterial action of oxaphenamide (p-oxyphenylsalicylamide), a cholagogue. This medium permits a single-stage combined isolation and identification of P. aeruginosa after 16-24 hrs incubation of inoculated material at 42 degrees C. If the material is incubated at 35-37 degrees C, isolation of P. putida and P. aeruginosa is possible, that are differentiated by a nitroreductase microtest within 3 hrs. The sensitivity and selective ability of the developed medium are superior to other media manufactured in this country and commercial media with cetrimide and irgasan, produced abroad.
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The taxonomic position of 23 strains isolated from mineral waters and previously grouped in the authentic pseudomonads on the basis of a phenotypic analysis (cluster IX, subclusters XIIIa and XIIIc of VERHILLE, S., ELOMARI, M., COROLER, L., IZARD, D., LECLERC, H. (Syst. Appl. Microbiol, 20, 137-149, 1997) has been genotypically further studied in the present work. On the basis of hybridization results, these strains were gathered into two new genomic groups for which we propose the names of Pseudomonas jessenii sp. nov. (Type strain CIP 105274) and Pseudomonas mandelii sp. nov. (Type strain CIP 105273). Deoxyribonucleic acid relatedness levels showed homologies ranging from 78 to 100% for Pseudomonas jessenii and from 77 to 100% for Pseudomonas mandelii. Furthermore, hybrization rates with 66 representative well characterized species or only partially characterized species of the genus Pseudomonas were below 53%, with delta Tm values of 7 degrees C and more. The mol% G + C content ranged from 57 to 58. The two new species presented basic morphological characteristics common to all pseudomonads. Various phenotypic features, such as denitrification, growth at 4 degrees C or 41 degrees C, trigonelline assimilation, alpha-L-glutamyl-L-histidine arylarmidase activity, growth on benzoate and meso-tartrate were found to differentiate Pseudomonas jessenii from Pseudomonas mandelii and from other Pseudomonas species. Pseudomonas jessenii encompassed a total of 9 strains from both phenotypic groups IX and XIIIa. Pseudomonas mandelii clustered a total of 13 strains from both phenotypic groups IX and XIIIc. Their clinical significance is unknown. The 16S rDNA of each type strain was sequenced and compared with the known sequences of the representative strains of the genus Pseudomonas. A phylogenetic tree was constructed to determine the intrageneric relationships within the genus Pseudomonas.
Pneumonia due to Pseudomonas aeruginosa occurs with increased frequency and high mortality in certain populations of patients. The potential of vaccination with a heptavalent lipopolysaccharide pseudomonas vaccine for specific protection of respiratory tissues from infection with Pseudomonas was evaluated with a guinea pig model of experimental pseudomonas pneumonia. Animals routinely responded to vaccination with a fourfold rise in titer of serum hemagglutinating antibody to Pseudomonas. Of 25 control animals, all but nine died after lung challenge with Pseudomonas, whereas vaccinated animals had a greater survival rate (22 of 25 animals survived; P less than 0.01). Rates of clearance of viable Pseudomonas from lung tissue were significantly greater in vaccinated animals than in controls during the first 6 hr after infection. Both gross and microscopic findings of lung tissue damage from pseudomonas pneumonia were less in vaccinated than in control animals. Thus, lipopolysaccharide pseudomonas vaccine appears to produce a local protective response in respiratory tissue against Pseudomonas.
We designed five Pseudomonas-selective soil extract NAA media containing the selective properties of trimethoprim and sodium lauroyl sarcosine and 0 to 100% of the amount of Casamino Acids used in the classical Pseudomonas-selective Gould's S1 medium. All of the isolates were confirmed to be Pseudomonas by a Pseudomonas-specific OprF antibody and a Pseudomonas-specific PCR targeting 16S ribosomal DNA. The Pseudomonas isolates were characterized by classical physiological tests, repetitive extragenic palindromic-PCR, Fourier transform infrared spectroscopy, and carbon source utilization patterns. Several of these analyses showed that the amount of Casamino Acids significantly influenced the diversity of the recovered Pseudomonas isolates. Furthermore, the data suggested that specific Pseudomonas subpopulations were represented on the nutrient-poor media. The NAA 1:100 medium, containing ca. 15 mg of organic carbon per liter, consistently gave significantly higher Pseudomonas CFU counts than Gould's S1 when tested on four Danish soils. NAA 1:100 may, therefore, be a better medium than Gould's S1 for enumeration and isolation of Pseudomonas from the low-nutrient soil environment.
A comparison was made of denitrification by Pseudomonas stutzeri, Pseudomonas aeruginosa, and Paracoccus denitrificans. Although all three organisms reduced nitrate to dinitrogen gas, they did so at different rates and accumulated different kinds and amounts of intermediates. Their rates of anaerobic growth on nitrate varied about 1.5-fold; concomitant gas production varied more than 8-fold. Cell yields from nitrate varied threefold. Rates of gas production by resting cells incubated with nitrate, nitrite, or nitrous oxide varied 2-, 6-, and 15-fold, respectively, among the three species. The composition of the gas produced also varied markedly: Pseudomonas stutzeri produced only dinitrogen; Pseudomonas aeruginosa and Paracoccus denitrificans produced nitrous oxide as well; and under certain conditions Pseudomonas aeruginosa produced even more nitrous oxide than dinitrogen. Pseudomonas stutzeri and Paracoccus denitrificans rapidly reduced nitrate, nitrite, and nitrous oxide and were able to grow anaerobically when any of these nitrogen oxides were present in the medium. Pseudomonas aeruginosa reduced these oxides slowly and was unable to grow anaerobically at the expense of nitrous oxide. Furthermore, nitric and nitrous oxide reduction by Pseudomonas aeruginosa were exceptionally sensitive to inhibition by nitrite. Thus, although it has been well studied physiologically and genetically, Pseudomonas aeruginosa may not be the best species for studying the later steps of the denitrification pathway.
In recent years, the interest in the use of bacteria for biological control of plant-pathogenic fungi has increased. We studied the possible side effects of coating barley seeds with the antagonistic strain Pseudomonas fluorescens DR54 or a commercial fungicide, imazalil. This was done by monitoring the number of indigenous Pseudomonas organisms and actinomycetes on barley roots during growth in soil, harvest after 50 days, and subsequent decomposition. Bacteria were enumerated by traditional plate spreading on Gould's S1 agar (Pseudomonas) and as filamentous colonies on Winogradsky agar (actinomycetes) and by two quantitative competitive PCR assays. For this we developed an assay targeting Streptomyces and closely related genera. DR54 constituted more than 75% of the Pseudomonas population at the root base during the first 21 days but decreased to less than 10% at day 50. DR54 was not successful in colonizing root tips. Initially, DR54 affected the number of indigenous Pseudomonas organisms negatively, whereas imazalil affected Pseudomonas numbers positively, but the effects were transient. Although plate counts were considerably lower than the number of DNA copies, the two methods correlated well for Pseudomonas during plant growth, but after plant harvest Pseudomonas-specific DNA copy numbers decreased while plate counts were in the same magnitude as before. Hence, Pseudomonas was 10-fold more culturable in a decomposition environment than in the rhizosphere. The abundance of actinomycetes was unaffected by DR54 or imazalil amendments, and CFU and quantitative PCR results correlated throughout the experiment. The abundance of actinomycetes increased gradually, mostly in numbers of DNA copies, confirming their role in colonizing old roots.
Chronic respiratory infection with Pseudomonas aeruginosa is a leading clinical problem among patients with cystic fibrosis. Because antimicrobial agents are usually ineffective in eradicating these infections, additional therapeutic or prophylactic measures should be considered. In this study, an experimental guinea pig model of chronic Pseudomonas aeruginosa bronchopneumonia was utilized to determine whether active immunization with lipopolysaccharide (LPS) P. aeruginosa antigen may favorably influence the course of this infection. Experimental pneumonia was established by tracheobronchial instillation of suspensions of microscopic agar beads, which were impregnated with viable P. aeruginosa. After 4 wk of infection, the geometric mean (reciprocal) passive hemagglutinating Pseudomonas antibody titer was 185+/-1.3, and lungs contained 16.8+/-4 x 10(3) colony-forming units Pseudomonas/ml of lung homogenate. Pseudomonas immunization, given prior to a 4-wk infection, resulted in significantly higher passive hemagglutinating titers (474+/-1.4; P < 0.05), lower numbers of viable Pseudomonas in lung tissues (2.4+/-0.6 x 10(3); P < 0.01), and reduced histopathology in lungs. In contrast, providing Pseudomonas immunization to animals 2 wk after pulmonary infection was established, offered no apparent benefit. Likewise, no protection was afforded by prophylactic immunization with a non-Pseudomonas LPS antigen (Escherichia coli J5 vaccine). Using a Raji cell assay, modified to detect circulating immune complexes in vaccinated and infected guinea pig sera, there was no evidence that active immunization increased the frequency of circulating immune complexes in infected guinea pigs. It is concluded that prophylactic immunization with Pseudomonas LPS antigen may confer protection from subsequent Pseudomonas bronchopneumonia, but that immunization during established infection is not beneficial.
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A strain of Gram negative bacteria was isolated from the surface soil of Wuying Hill at Jinan, Shandong province with Gause's medium in 1973. It is a strain of antagonistic bacteria for hysterocervicoma, hepatoma and melanoma of mice screened from 2100 strains of bacteria. It is also antagonistic to Staphylococcus aureus, Bacillus subtilis and Micrococcus. It is a Gram negative bacterium with lophotrichous polar flagella. Straight rods in shape or with a little slightly curved rods, 0.5-0.6 X 1-2 microns, randomly arranged, poly-beta-hydroxybutyrate granules are accumulated in cells after 2-5 days cultivation. Water green soluble pigment and green fluorescent pigment are produced. Respiratory metabolism, chemoorganotroph, many carbon-containing organic compounds can be used as carbon sources, such as glucose, trehalose, ethanol, cellulobiose, fucose, arginine and betaine, but propionic acid or tartaric acid is not utilized. Inorganic nitrogen containing compounds can be used ae the sole source of nitrogen. No growth factor is necessary for growth. Gelatin is hydrolyzed. Starch and cellulose are not hydrolyzed. Nitrate is not reduced. Arginine dihydrolase is produced. Levan is produced from sucrose. Growth occurs from 7 degrees C to 37 degrees C and from pH 5.65-8.40. No growth occurs at 40 degrees C and at pH value below 4.86. It can not grow autotrophically with hydrogen. Its G + C contents in DNA is 58.1 mol%. DNA-DNA hybridization experiments reveals a relatedness value of 58.6% between this strain and Ps. fluorescens. The above evidence shows that this strain differs from all species known in Pseudomonas, such as Pseudomonas fluorescens group. Pseudomonas caryophylli, Pseudomonas cepacia, Pseudomonas marginata, Pseudomonas acidovorans, Pseudomonas testosteroni and Pseudomonas delafieldii.(ABSTRACT TRUNCATED AT 250 WORDS)
A total of 133 patients with cystic fibrosis have been followed for up to 5 years with monthly examinations including bacteriological examinations of sputum. Sera from the patients were examined by means of crossed immunoelectrophoresis for the occurence and number of precipitating antibody specificites against Pseudomonas aeruginosa. Poor prognosis in cystic fibrosis was associated with chronic colonization (9 months - more than 5 years) of the respiratory tract with mucoid Pseudomonas aeruginosa, and with an onset of the chronic colonization before puberty. Among the patients with chronic Pseudomonas aeruginosa colonization, poor prognosis was associated with high numbers of precipitins against antigens from these bacteria (up to 61). The number of Pseudomonas aeruginosa precipitins increased on an average with five per year in chronically colonized patients. Rapidly increasing number of precipitins was associated with poor prognosis. Patients with any degree of impairment of the ventilatory function and any changes on the chest radiographs could contract chronic Pseudomonas aeruginosa colonization. Poor ventilatory function and severe changes on the chest radiographs was associated with high numbers of Pseudomonas aeruginosa precipitins and with poor prognosis. Although many O groups of Pseudomonas aeruginosa were found in the chronically colonized group of patients, 53% of the patients harboured strains belonging to O group 3 or 3/9, and the highest numbers of precipitins were found in serum from these patients.
Sixteen Gram-negative, rod-shaped, non-spore-forming isolates were obtained from a nitrifying inoculum. Analysis of repetitive sequence-based PCR and SDS-PAGE banding patterns, 16S rRNA gene sequence analysis and DNA-DNA hybridizations showed that the isolates belonged to various groups within the genus Pseudomonas. One group of isolates could be assigned to Pseudomonas migulae and a second to Pseudomonas veronii. Two groups could be differentiated genotypically from each other and from all other currently known Pseudomonas species. Analysis of the fatty acid composition and physiological and biochemical tests allowed differentiation of these groups from their closest phylogenetic neighbours and they therefore represent two novel species within the genus Pseudomonas, for which the names Pseudomonas peli sp. nov. and Pseudomonas borbori sp. nov. are proposed, with strains LMG 23201(T) (=DSM 17833(T)=R-20805(T)) and LMG 23199(T) (=DSM 17834(T)=R-20821(T)), respectively, as the type strains.
The plc gene for phospholipase of Pseudomonas aeruginosa, able to be transcribed only from its own promoter, has been introduced into Escherichia coli, Pseudomonas aeruginosa and Pseudomonas putida cells in the recombinant plasmid pPMS21 of a wide host range. The expression of plc gene in all recipient cells has been shown to be phosphate regulated. The fact emphasizes the identity of pho-regulation systems in Escherichia coli and Pseudomonas cells. The level of phospholipase activity is similar in Pseudomonas putida and Pseudomonas aeruginosa under the conditions of the gene derepression, while in Escherichia coli cells the level does not exceed 10% of activity registered in Pseudomonas cells.