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PubMed1995

[Study on the pathogenetic role of alginate produced by mucoid Pseudomonas aerugiosa in diffuse panbronchiolitis].

It has scarcely been known that the pathogenetic role of mucoid Pseudomonas aeruginosa being colonised on the airway surface in diffuse panbronchiolotis DPB. The role of alginate, a main component of mucoid substance of Pseudomonas aeruginosa was demonstrated in reference to DPB. 1. Clinical Observation Serum titer of anti-alginate antibody IgG in the group of Pseudomonas-positive DPB was higher than that of the groups of Pseudomonas-negative DPB (p < 0.01) and healthy volunteers (p < 0.01). The concentration of immune complex in Pseudomonas-positive DPB group at serum level was also higher than that of the above two groups (p < 0.01), and it was well correlated between activity in the patient's symptom and the patient's prognosis. 2. Experimental Observation In the immunised mice made by free alginate injections, a lymphocyte infiltration around small vessels and small airways in lung was characteristically found at the early stage after the inhalation with mucoid Pseudomonas aeruginosa PT1252. It disappeared 14-15 days after the inhalation. By repeating the inhalation for 6 days, such a lymphocyte infiltration had been persisted and lymphocyte granulomatous change was formed around small airways. The transformation and narrowing of the small airway occurred by lymphocyte granulomatous change. At the same time, some degree of neutrophil infiltration into the airway was also observed. These findings were closely similar to that of human diffuse panbronchiolitis. 3. Conclusive Words From the above, the pathogenetic role of alginate in mucoid Psuedomonas aerginosa colonised on airway surface in DPB patient will be explained as follows. Local immunoreaction of antigen and antibody through alginate evolved lymphocyte infiltration around small airway area. A persistent localization of antigen (alginate) makes such an immunoreaction repeat. Consequently, lymphocyte-granulomatous change is formed around the small airway. On the other hand, a state of excess antigen introduced by long term colonization of mucoid Pseudomonas aeruginosa forms an immune complex in the host side. Neutrophil combined with the immune complex deposited on the airway surface may act in a destructive manner for the lung tissue of DPB patient.

Adult↗
PubMed1981

New selective agent for isolation of Pseudomonas aeruginosa.

Results of minimal inhibitory concentration tests with a diversity of bacterial strains showed that 9-chloro-9-(4-diethylaminophenyl)-10-phenylacridan (C-390) inhibited the growth of all microorganisms tested (other than Pseudomonas aeruginosa) at 25 microgram/ml or less, whereas MICs obtained for P. aeruginosa ranged from to to greater than 100 microgram/ml. Therefore, C-390 was evaluated as a potential selective agent for P. aeruginosa in pseudomonas agar F. Recovery tests were conducted on this medium with 53 strains o P. aeruginosa, and the results were compared to those obtained in similar tests on commercially available selective media, i.e., pseudomonas isolation agar and Pseudosel agar. The results of these comparisons indicated that pseudomonas agar F with C-390 was significantly less inhibitory than Pseudosel agar and pseudomonas isolation agar and more selective than pseudomonas isolation agar. The incorporation of C-390 in pseudomonas agar F also provided a medium that was both selective and differential. Preliminary evidence also suggested that C-390 may be added to other basal media with comparable results.

Acridines↗
PubMed1992

Characterization of a novel Pseudomonas sp. that mineralizes high concentrations of pentachlorophenol.

A pentachlorophenol (PCP)-mineralizing bacterium was isolated from polluted soil and identified as Pseudomonas sp. strain RA2. In batch cultures, Pseudomonas sp. strain RA2 used PCP as its sole source of carbon and energy and was capable of completely degrading this compound as indicated by radiotracer studies, stoichiometric release of chloride, and biomass formation. Pseudomonas sp. strain RA2 was able to mineralize a higher concentration of PCP (160 mg liter-1) than any previously reported PCP-degrading pseudomonad. At a PCP concentration of 200 mg liter-1, cell growth was completely inhibited and PCP was not degraded, although an active population of Pseudomonas sp. RA2 was still present in these cultures after 2 weeks. The inhibitory effect of PCP was partially attributable to its effect on the growth rate of Pseudomonas sp. strain RA2. The highest specific growth rate (mu = 0.09 h-1) was reached at a PCP concentration of 40 mg liter-1 but decreased at higher or lower PCP concentrations, with the lowest mu (0.05 h-1) occurring at 150 mg liter-1. Despite this reduction in growth rate, total biomass production was proportional to PCP concentration at all PCP concentrations degraded by Pseudomonas sp. RA2. In contrast, final cell density was reduced to below expected values at PCP concentrations greater than 100 mg liter-1. These results indicate that, in addition to its effect as an uncoupler of oxidative phosphorylation, PCP may also inhibit cell division in Pseudomonas sp. strain RA2.(ABSTRACT TRUNCATED AT 250 WORDS)

Biodegradation, Environmental↗
PubMed1987

Characterization by pyocine typing and serotyping of oral and sputum strains of Pseudomonas aeruginosa isolated from cystic fibrosis patients.

Oral and sputum isolates of Pseudomonas aeruginosa in patients with cystic fibrosis were investigated. Of the 17 patients studied, 12 patients (71%) yielded both mucoid and nonmucoid variants of Pseudomonas aeruginosa from sputum and (or) various oral ecological sites, such as buccal mucosa, tongue dorsum, dental plaques, and saliva. A total of 51 strains of mucoid and nonmucoid Pseudomonas aeruginosa were isolated from these patients and were phenotypically characterized by both pyocine typing and serotyping. Five patients (42%) were colonized or infected by a single strain of Pseudomonas aeruginosa, whereas 7 patients (58%) were cocolonized or coinfected by two or more phenotypically different strains of Pseudomonas aeruginosa. To understand the mechanisms involved in Pseudomonas aeruginosa colonization, it may be necessary to identify multiple isolates of Pseudomonas aeruginosa not only from the sputum but also from the various oral ecological sites and to further explore the role of the oral cavity in this colonization.

Adolescent↗
PubMed1985

The effects of systemic immunization of pulmonary clearance of Pseudomonas aeruginosa.

Systemic immunization with gram-negative organisms enhances the subsequent pulmonary clearance of these organisms. We studied the early time course of this phenomenon and related it to the time of appearance of polymorphonuclear leukocytes (PMN) and anti-Pseudomonas antibody in bronchoalveolar lavage (BAL). Mice were immunized intraperitoneally twice, separated by 1 wk, with 10(8) formalin-treated Pseudomonas aeruginosa. Two weeks later, they received an intrabronchial inoculum of 2.9 X 10(6) or 4.6 X 10(7) Pseudomonas organisms. Two, 4, and 6 h later, clearance and total PMN and anti-Pseudomonas antibody in the BAL were assessed. Clearance was enhanced in immunized mice at the lower inoculum. At the higher inoculum, bacteria were growing in lungs of both groups, although they were inhibited in immunized mice. Total PMN in the BAL increased progressively in both groups of mice, but net recruitment was diminished with the high inoculum. There were significant differences in the PMN in the BAL between control and immunized mice with high inoculum. Anti-Pseudomonas IgG first appeared in the BAL at 2 h, anti-Pseudomonas IgM at 6 h. These data suggest that anti-Pseudomonas IgG is an effective early pulmonary opsonin. Further, with high inoculums, immunization may aid pulmonary defenses by diminishing the magnitude of the decrement of PMN in the lung.

Animals↗
PubMed1992

Production of the Pseudomonas aeruginosa neuraminidase is increased under hyperosmolar conditions and is regulated by genes involved in alginate expression.

The pathogenesis of Pseudomonas aeruginosa infection in cystic fibrosis (CF) is a complex process attributed to specific characteristics of both the host and the infecting organism. In this study, the properties of the PAO1 neuraminidase were examined to determine its potential role in facilitating Pseudomonas colonization of the respiratory epithelium. The PAO1 neuraminidase was 1000-fold more active than the Clostridium perfringens enzyme in releasing sialic acid from respiratory epithelial cells. This effect correlated with increased adherence of PAO1 to epithelial cells after exposure to PAO1 neuraminidase and was consistent with in vitro studies demonstrating Pseudomonas adherence to asialoganglioside receptors. The regulation of the neuraminidase gene nanA was examined in Pseudomonas and as cloned and expressed in Escherichia coli. In hyperosmolar conditions neuraminidase expression was increased by 50% (P less than 0.0004), an effect which was OmpR dependent in E. coli. In Pseudomonas the osmotic regulation of neuraminidase production was dependent upon algR1 and algR2, genes involved in the transcriptional activation of algD, which is responsible for the mucoid phenotype of Pseudomonas and pathognomonic for chronic infection in CF. Under the hyperosmolar conditions postulated to exist in the CF lung, nanA is likely to be expressed to facilitate the initial adherence of Pseudomonas to the respiratory tract.

Alginates↗
PubMed2004

Catechol 2,3-dioxygenase from Pseudomonas sp. strain ND6: gene sequence and enzyme characterization.

The catechol 2,3-dioxygenase (C23O) gene in naphthalene catabolic plasmid pND6-1 of Pseudomonas sp. ND6 was cloned and sequenced. The C23O gene was consisted of 924 nucleotides and encoded a polypeptide of molecular weight 36 kDa containing 307 amino acid residues. The C23O of Pseudomonas sp. ND6 exhibited 93% and 89% identities in amino acid sequence with C23Os encoded by naphthalene catabolic plasmid NAH7 from Pseudomonas putida G7 and the chromosome of Pseudomonas stutzeri AN10 respectively. The Pseudomonas sp. ND6 C23O gene was overexpressed in Escherichia coli DH 5alpha using the lac promoter of pUC18, and its gene product was purified by DEAE-Sephacel and Phenyl-Sepharose CL-4B chromatography. The enzymology experiments indicated that the specific activity and thermostability of C23O from Pseudomonas sp. ND6 were better than those of C23O from Pseudomonas putida G7.

Amino Acid Sequence↗
PubMed1989

Degradation of 2-chlorobenzoate by Pseudomonas cepacia 2CBS.

A bacterium was isolated from water by enrichment on 2-chlorobenzoate as sole source of carbon and energy. Based on morphological and physiological properties, this microorganism was assigned to the species Pseudomonas cepacia. The organism was designated Pseudomonas cepacia 2CBS. During growth on 2-chlorobenzoate, the chlorine substituent was released quantitatively, and a small amount of 2,3-dihydroxybenzoate accumulated in the culture medium. Mutants of Pseudomonas cepacia 2CBS were induced by treatment with N-methyl-N'-nitro-N-nitrosoguanidine. Some of these mutants produced catechol from 2-chlorobenzoate. Other mutants accumulated the meta-cleavage product of catechol, 2-hydroxy-cis,cis-muconic acid semialdehyde. In crude cell-free extracts of Pseudomonas cepacia 2CBS, an enzyme was detected which catalysed the conversion of 2-chlorobenzoate to catechol. Molecular oxygen, NADH and exogenous Fe2+ were required for activity. Stoichiometric amounts of chloride were released. Experiments with 18O2 revealed that both oxygen atoms in the hydroxyl groups of the product were derived from molecular oxygen. Thus, the enzyme catalysing the conversion of 2-chlorobenzoate was identified as 2-chlorobenzoate 1,2-dioxygenase (1,2-hydroxylating, dehalogenating, decarboxylating). 2-Chlorobenzoate 1,2-dioxygenase from Pseudomonas cepacia 2CBS was shown to be a multicomponent enzyme system. The activities of catechol 2,3-dioxygenase and catechol 1,2-dioxygenase were detected in crude cell-free extracts. The activity of catechol 2,3-dioxygenase was 60 times higher than the activity of catechol 1,2-dioxygenase, indicating that catechol is mainly degraded via meta-cleavage in Pseudomonas cepacia 2CBS. No enzyme was found which converted 2,3-dihydroxybenzoate, suggesting that this compound is a dead-end metabolite of 2-chlorobenzoate catabolism. A pathway for the degradation of 2-chlorobenzoate by Pseudomonas cepacia 2CBS is proposed.

Catechols↗
PubMed1998

Endothelium-dependent vasodilation in response to Pseudomonas aeruginosa lipopolysaccharide: an in vitro study on canine arteries.

Early systemic arterial hypotension is a common clinical feature of Pseudomonas septicemia. To determine if Pseudomonas aeruginosa endotoxin induces the release of endothelium-derived nitric oxide (EDNO), an endogenous nitrovasodilator, segments of canine femoral, renal, hepatic, superior mesenteric, and left circumflex coronary arteries were suspended in organ chambers (physiological salt solution, 95% O2/5% CO2, pH 7.4, 37 degrees C) to measure isometric force. In arterial segments contracted with 2 microM prostaglandin F2 alpha, Pseudomonas endotoxin (lipopolysaccharide (LPS) serotype 10(Habs) from Pseudomonas aeruginosa (0.05 to 0.50 mg/ml) induced concentration-dependent relaxation of segments with endothelium (P < 0.05) but no significant change in tension of arteries without endothelium. Endothelium-dependent relaxation in response to Pseudomonas LPS occurred in the presence of 1 microM indomethacin, but could be blocked in the coronary artery with 10 microM NG-monomethyl-L-arginine (L-NMMA), a competitive inhibitor of nitric oxide synthesis from L-arginine. The inhibitory effect of L-NMMA on LPS-mediated vasorelaxation of the coronary artery could be reversed by exogenous 100 microM L-arginine but not by 100 microM D-arginine. These experiments indicate that Pseudomonas endotoxin induces synthesis of nitric oxide from L-arginine by the vascular endothelium. LPS-mediated production of EDNO by the endothelium, possibly through the action of constitutive nitric oxide synthase (NOSc), may decrease systemic vascular resistance and may be the mechanism of early hypotension characteristic of Pseudomonas septicemia.

Animals↗
PubMed2001

Mucin secretion in the rat tracheal epithelial cells by epidermal growth factor and Pseudomonas aeruginosa extracts.

BACKGROUND: Hypersecretion of mucin due to goblet cell hyperplasia is frequently encountered in many chronic airway diseases, such as chronic bronchitis, bronchiectasis, bronchial asthma and cystic fibrosis. Even in normal individuals, viral infection or bacterial pneumonia frequently provoke huge amounts of bronchial secretions which may cause airway obstruction. The production of mucin was regulated by epidermal growth factor (EGF) in vitro. To know whether this EGF system regulates mucin secretion in vivo and Pseudomonas also stimulates the mucin secretion by the same pathway, we studied these relationships in the cultured rat tracheal epithelial cells. METHODS: Rat tracheal epithelial cells were obtained by pronase dissociation from the male Fisher 344 rats. When cells became confluent, they were divided into 6 groups and stimulated with either EGF for 24 hours or Pseudomonas extracts for 12 hours with or without selective EGF-R tyrosine kinase inhibitor tyrphostin AG1478. RESULTS: We found that both EGF and Pseudomonas extracts phosphorylated the tyrosine residue in the EGF receptor from the rat tracheal epithelial cells and this tyrosine phosphorylation was nearly completely blocked by selective EGF-R tyrosine kinase inhibitor tyrphostin AG1478. The mucin secretion was also stimulated by either EGF or Pseudomonas extracts but more strong secretion of mucin and MUC5AC gene expression in the rat tracheal epithelial cell was done by Pseudomonas extracts. CONCLUSION: These data suggest that Pseudomonas secretes the mucin by way of the EGF receptor and MUC5AC gene expression and the inhibitors of EGF receptor tyrosine phosphorylation would be useful to prevent the huge production of mucin due to Pseudomonas aeruginosa lung infection.

Animals↗
PubMed2006

[Isolation and characterization of a new Pseudomonas strain against Phytophthora capsici].

One Pseudomonas strain GP72, which was against Phytophthora capsici, was isolated from green pepper rhizosphere in Jiangsu province. It had distinctively inhibitive effect on several kinds of pathogenic fungi; mostly of them are soilborne pathogens. Therefore, this strain may be used for an effective biocontrol strain in the crop protection. The morphological, biochemical and physiological characteristics, Biolog GN, G + C mol% content and 16S rDNA sequence analysis of this strain were studied. In comparison and conclusion of all the experimental data, GP72 is identified as Pseudomonas chlororaphis. The strain is single-cellular and motile by means of single polar flagellum. It was not able to accumulate ploy-beta-hydroxybutyrate. Compared to P. aureofaciens 30-84, the strain was able to survive at the concentration of 5% NaCl. It could strongly utilize 45 of 95 carbon-substrates; weakly utilize 6 of the whole carbon-substrates and never utilize 43 of the whole carbon-substrates resulting from analysis of Biolog GN, bearing the similarity probability of 98% with Pseudomonas chlororaphis and with the similarity index 0.72. The G + C content of the strain DNA was 65.1 mol% using the thermal denaturation method. A phylogenetic tree was constructed by comparing with the validly published 16S rDNA sequences of the related type strains from GenBank, using the Neighbor-Joining method of Saitou and Nei and the Clustal X program to do the multiple alignments. The tree topology was tested by a bootstrap analysis of 1000 samplings. The overall similarity value between strain GP72 and typical is the closest in the phylogenetic tree. For the latest taxonomical development has put genus Pseudomonas aureofaciens to the genus Pseudomonas chlororaphis, then it is appropriate to say that GP72 belongs to the genus Pseudomonas chlororaphis. This is the first time in China to report that a strain of Pseudomonas chlororaphis was isolated from green pepper rhizosphere, having a strong inhibitive effect on Phytophthora capsici and other soilborne pathogenic fungus. The other characteristics and the biocontrol mechanism are yet to be further studied.

Base Composition↗
PubMed1988

An outbreak of Pseudomonas cepacia bacteremia associated with a contaminated intra-aortic balloon pump.

In January 1983, symptomatic Pseudomonas cepacia bacteremia developed in two patients in the cardiothoracic intensive care unit within 3 days after cardiac operation and insertion of an intra-aortic balloon pump. An epidemiologic and microbiologic investigation revealed that both patients required intra-aortic balloon pumping for circulatory support and that the water reservoir of the intra-aortic balloon pump (SMEC, Inc., Cookeville, Tenn.) contained more than 10(5) Pseudomonas cepacia per milliliter. This organism was also recovered from the purge button and on-off switch of the pump and from the hands of a health care worker who manipulated the water reservoir of the intra-aortic balloon pump. Agarose gel electrophoresis of lysates of Pseudomonas cepacia with rapid methods of deoxyribonucleic acid preparation revealed three identical plasmids of the Pseudomonas cepacia from the water reservoir of the intra-aortic balloon pump and from the infected patients. Transmission from the worker's hands to patients presumably occurred by inoculation of the intravascular lines during management. No additional cases of Pseudomonas cepacia bacteremia were observed after the unit was replaced with a nonwater reservior intra-aortic balloon pump. This report substantiates the ability of Pseudomonas cepacia to multiply in water and to cause epidemic bacteremia, identifies the water reservoir of the SMEC intra-aortic balloon pump as a previously unrecognized hazard for the patient requiring intra-aortic balloon pumping, and documents the value of plasmid analysis in elucidating the mode of transmission of nosocomial Pseudomonas cepacia infections.

Aged↗
PubMed1994

Clinical significance of exit-site infections due to Xanthomonas in CAPD patients: a comparison with Pseudomonas infection.

We have assessed the clinical significance of exit-site infections secondary to Xanthomonas maltophilia in continuous ambulatory peritoneal dialysis (CAPD) patients, and compared them with episodes due to Pseudomonas. The study was a retrospective survey of all episodes of Xanthomonas and Pseudomonas-related exit-site infections (ESI) in all patients treated in our unit between 1984 and 1992. Thirteen episodes of Xanthomonas-related ESI were observed in eight patients and 17 episodes of Pseudomonas-related ESI were seen in 15 patients. Xanthomonas-related ESI was frequently associated with other microorganisms, while Pseudomonas-related ESI was not (66% versus 5%, P < 0.02). Only one episode of Xanthomonas-related ESI resulted in peritonitis and subsequent catheter removal, after 15 months of resistant colonization. Another case was considered to be chronic and indolent, as the Xanthomonas-related ESI continued after 23 months of local treatment. The other 11 episodes were resolved either without treatment or with an antibiotic cream after 7-120 days. However, all but two episodes of Pseudomonas-related ESI required intravenous antibiotics (usually ceftazidime); seven patients developed peritonitis, and 11 required surgical catheter manipulation (five external cuff extrusion, and six catheter removal) (1/13 Xanthomonas-related versus 11/17 Pseudomonas-related ESI, P < 0.03). Most Xanthomonas-related ESI do not lead to peritonitis, and constitute a mild condition, easily treatable without parenteral antibiotics or catheter replacement. The appearance of other associated organisms and the favourable evolution with local treatment suggest a saprophytic behaviour for Xanthomonas in our CAPD patients. On the contrary, Pseudomonas-related ESI is usually severe, requires parenteral antibiotics, frequently leads to peritonitis, and requires catheter replacement.

Adult↗
PubMed1985

Enzyme-linked immunosorbent assay for detection of antibodies to Pseudomonas aeruginosa exoproteins.

Enzyme-linked immunosorbent assays were developed with four purified Pseudomonas aeruginosa extracellular proteins (exotoxin A, elastase, alkaline protease, and phospholipase C) to determine antibody levels in sera from healthy subjects and the serological response in patients colonized or infected with Pseudomonas aeruginosa. Five of 39 burn patients with wounds colonized by Pseudomonas aeruginosa had elevated antibody titers to alkaline protease. Response to the other antigens was found in only a few patients. Pseudomonas aeruginosa infections (septicemia, osteitis, pneumonia etc.) resulted in increased antibody levels to exotoxin A or phospholipase C in 15 of 22 patients. These findings suggest that repeated determinations of antibodies to Pseudomonas aeruginosa exotoxin A and phospholipase C might be used to monitor therapy in certain patients with osteitis and other deep Pseudomonas infections.

ADP Ribose Transferases↗
PubMed1978

Pseudomonas colonization in patients with spinal cord injury.

Pseudomonas has been an important cause of urinary tract infection in patients with spinal cord injuries. To determine the possible reservoirs of Pseudomonas, colonization with Pseudomonas was studied in 52 inpatients and 28 outpatients with spinal cord injuries. Body sites, the environment, and hospital staff were cultured. There was a high prevalence of colonization of the urethra, perineum, and rectum. Pseudomonas was isolated from one or more of these sites in 85% of male inpatients and in 71% of male outpatients. Significant bacteriuria with Pseudomonas was found in 37% of inpatients and 13% of male outpatients. Urethral colonization in men was significantly associated with the use of the external urethral catheter. Culturing the patient's perineum was a sensitive indicator of patient colonization. The urinary drainage bag was another frequent reservoir of Pseudomonas. More than one-half of these patients did not have significant bacteriuria and presumably the drainage bag was colonized from the urethra or perineum. The rates of urethral, perineal, and rectal carriage were higher than those described previously. These rates may be accounted for by the use of the external urethral catheters. Other factors, such as rectal manipulation, and fecal incontinence may be important in these groups of patients.

Bacteriuria↗
PubMed1982

Detection by enzyme-linked immunosorbent assays of antibody specific for Pseudomonas proteases and exotoxin A in sera from cystic fibrosis patients.

Enzyme-linked immunosorbent assays were developed to measure serum antibody specific for Pseudomonas elastase, alkaline protease, and exotoxin A. Antibody responses to each Pseudomonas antigen were measured in cystic fibrosis (CF) patients who were not colonized with Pseudomonas aeruginosa, in those who were colonized, in those who were chronically infected with this organism, and in control subjects. Antibody levels for each antigen in the colonized and infected CF patients were higher than levels in uncolonized CF patients or non-CF control subjects. The antibody responses to elastase were similar in patients of the colonized and infected groups. However, infected CF patients had significantly elevated levels of antibody to exotoxin A (P less than 0.01) and alkaline protease (P less than 0.05) when compared with patients simply colonized with P. aeruginosa. These findings confirm that Pseudomonas alkaline protease, elastase, and exotoxin A are produced by Pseudomonas strains which colonize and infect CF patients. As an adjunct to established procedures (X-ray, microbiological culture, etc.), the antitoxin and anti-protease enzyme-linked immunosorbent assays may be clinically useful tests for differentiating colonized CF patients from those who have more severe Pseudomonas pulmonary infections.

ADP Ribose Transferases↗
PubMed2000

Role of Microcolony Formation in the Protistan Grazing Defense of the Aquatic Bacterium Pseudomonas sp. MWH1.

A BSTRACTThe defense strategy of the aquatic bacterium Pseudomonas sp. MWH1 against flagellate grazing was investigated in chemostat and batch experiments. The influence of predation on the Pseudomonas population was studied in the absence and presence of a potential competitor ( Vibrio sp. CB5), as well as under starvation conditions and in a situation of unlimited growth. In the competition experiment the two bacterial strains were distinguished by immunofluorescence microscopy. When the Pseudomonas strain was cultured in the absence of the predator Ochromonas sp. DS, only mobile single cells were detectable. Grazing by this bacterivorous flagellate resulted in all experiments in the occurrence of a Pseudomonas subpopulation, which grew as floclike, suspended microcolonies. These microcolonies consisted of up to approximately 1,000 cells and were, because of their large size, protected against flagellate grazing. The microcolony subpopulation dominated the total Pseudomonas population in situations of high grazing pressure at a wide range of bacterial growth conditions. Thus, the formation of the microcolonies is interpreted as a successful grazing-defense strategy, which is effective under several growth conditions, allowing for the survival of the strain even when substrate depletion is combined with strong grazing pressure. Batch culture experiments demonstrated that the change in morphology of Pseudomonas sp. MWH1 is not controlled by growth rate, although no formation of microcolonies was observed after the addition of 0.2-&mgr;m-filtered flagellate cultures to Pseudomonas cultures, indicating that a chemical trigger released by the flagellate is not involved in the control of this defense mechanism.

Journal Article↗
PubMed2003

Synthetic peptide vaccine and antibody therapeutic development: prevention and treatment of Pseudomonas aeruginosa.

Pseudomonas aeruginosa and Pseudomonas maltophilia account for 80% of opportunistic infections by pseudomonads. Pseudomonas aeruginosa is an opportunistic pathogen that causes urinary tract infections, respiratory system infections, dermatitis, soft tissue infections, bacteremia, and a variety of systemic infections, particularly in patients with severe burns, and in cancer and AIDS patients who are immunosuppressed. Pseudomonas aeruginosa is notable for its resistance to antibiotics, and is therefore a particularly dangerous pathogen. Only a few antibiotics are effective against Pseudomonas, including fluoroquinolones, gentamicin, and imipenem, and even these antibiotics are not effective against all strains. The difficulty treating Pseudomonas infections with antibiotics is most dramatically illustrated in cystic fibrosis patients, virtually all of whom eventually become infected with a strain that is so resistant that it cannot be treated. Since antibiotic therapy has proved so ineffective as a treatment, we embarked on a research program to investigate the development of a synthetic peptide consensus sequence vaccine for this pathogen. In this review article we will describe our work over the last 15 years to develop a synthetic peptide consensus sequence anti-adhesin vaccine and a related therapeutic monoclonal antibody (cross-reactive to multiple strains) to be used in the prevention and treatment of P. aeruginosa infections. Further, we describe the identification and isolation of a small peptide structural element found in P. aeruginosa strain K (PAK) bacterial pili, which has been proven to function as a host epithelial cell-surface receptor binding domain. Heterologous peptides are found in the pili of all strains of P. aeruginosa that have been sequenced to date. Several of these peptide sequences have been used in the development of an consensus sequence anti-adhesin vaccine targeted at the prevention of host cell attachment and further for the generation of a monoclonal antibody capable of prevention and treatment of existing infections.

Antibodies, Bacterial↗