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At least 451 records · Page 25Linked to original sources
PubMed1994

[Production of elastase, exotoxin A and alkaline protease during bronchopulmonary exacerbations in patients with mucoviscidosis chronically infected by Pseudomonas aeruginosa].

The authors have studied the production of exoproteins by Pseudomonas aeruginosa in the sputa of 18 patients suffering from cystic fibrosis, during 29 bronchopulmonary exacerbations and also after the recovery of a stable state. Significant levels of exoproteins were detected but with a large heterogenity of intra and inter individual variations. A significant decrease in the production of the three exoproteins was found after twelve days of antibiotherapy, without any correlation between exoprotein levels and colony forming units in the sputa. During the intercrisis phase, exoproteins levels were practically undetectable. These facts and the good correlation between clinical symptoms support the hypothesis of a renewal of virulence of Pseudomonas aeruginosa during these periods of bronchopulmonary exacerbation in cystic fibrosis.

Adolescent↗
PubMed1985

The influence of immunoglobulin on the development of Pseudomonas aeruginosa infection in an immunocompromised mouse model.

Pretreatment with normal immunoglobulin G (normal IgG) isolated from human placental blood, in secondary immune deficiency after anaesthesia, surgery and corticosteroid therapy seems to be an effective protection against bacterial infection in clinical practice. For this purpose, we tried to verify the effectiveness of normal IgG in prevention of bacterial infection in an animal model. The influence of treatment with normal human IgG has been studied in mice exposed to a sublethal infection with Pseudomonas aeruginosa in various states of immunocompetence such as under anaesthesia and corticosteroid therapy. Results, evaluated as percentages of survivors, confirm significant protection against infection with P. aeruginosa despite immunodepression with hydrocortisone and anaesthesia (96.6% of survivors in the group treated with IgG as opposed to 30% for the untreated corresponding group--P less than 0.001).

Anesthesia↗
PubMed1995

Effect of high-affinity anti-Pseudomonas aeruginosa lipopolysaccharide antibodies induced by immunization on the rate of Pseudomonas aeruginosa infection in patients with cystic fibrosis.

Patients with cystic fibrosis (CF; N = 26) and with no prior history of infection with Pseudomonas aeruginosa were immunized with an octavalent O-polysaccharide-toxin A conjugate vaccine. During the next 4 years, 16 patients (61.5%) remained free of infection and 10 (38.5%) became infected. Total serum antilipopolysaccharide (LPS) antibody levels induced by immunization were comparable in infected and noninfected patients. In contrast, 12 of 16 noninfected versus 3 of 10 infected patients (p = 0.024) mounted and maintained a high-affinity anti-LPS antibody response. When compared retrospectively with the rate in a group of age- and gender-matched, nonimmunized, noncolonized patients with CF, the rate at which P. aeruginosa infections were acquired was significantly lower (p < or = 0.02) among all immunized versus nonimmunized patients during the first 2 years of observation. Subsequently, only those immunized patients who maintained a high-affinity anti-LPS antibody response had a significant reduction (p < or = 0.014) in the rate of infection during years 3 and 4. Smooth, typeable strains of P. aeruginosa predominated among immunized patients; rough, nontypeable strains were most frequently isolated from nonimmunized patients. Mucoid variants were isolated from one immunized patient versus six nonimmunized patients. These results indicate that the induction of a high-affinity P. aeruginosa anti-LPS antibody response can influence the rate of infection in patients with CF.

Adolescent↗
PubMed2005

Use of phage display to identify potential Pseudomonas aeruginosa gene products relevant to early cystic fibrosis airway infections.

Pseudomonas aeruginosa airway infections are a major cause of morbidity and mortality in patients with cystic fibrosis. Treatment of established infections is difficult, even with microbiologically active agents. Thus, prevention of infection is an important goal of management. Isolates from cystic fibrosis patients appear to originate from the environment but adapt to the milieu of the airway of the cystic fibrosis patient and evolve toward a common phenotype. Identification of the antigens expressed early in infection may lead to novel targets for vaccine development. Immunogenic peptides were identified in a J404 random nonapeptide phage display library with serum from cystic fibrosis patients obtained within the first year of P. aeruginosa infection. One hundred sixty-five reactive clones were verified by plaque lift assays, and their inserts were sequenced. The sequenced nonapeptides were compared with the published sequence of strain PAO1, identifying homologies to 76 genes encoding outer membrane and secreted proteins. The majority of these were proteins involved in small-molecule transport, membrane structural proteins, and secreted factors. An in silico analysis was performed that suggested that the occurrence of multiple matches to predominantly outer membrane and secreted proteins was not attributable to random chance. Finally, gene expression array data from early isolates of P. aeruginosa from cystic fibrosis patients was compared with the results from phage display analysis. Eleven outer membrane and secreted proteins were common between the two data sets. These included genes involved in iron acquisition, antibiotic efflux, fimbrial biogenesis, and pyocin synthesis. These results demonstrate the feasibility and validity of this novel approach and suggest potential targets for future development.

Antibodies, Bacterial↗
PubMed1988

Specific and nonspecific imaging of localized Fisher immunotype 1 Pseudomonas aeruginosa infection with radiolabeled monoclonal antibody.

To determine if radiolabeled specific antibodies directed against bacterial antigens could be used to detect sites of infection, gamma camera imaging studies were performed in animals infected with Pseudomonas aeruginosa. Murine monoclonal antibodies (Mabs) directed against Fisher Immunotype 1 Pseudomonas aeruginosa and a nonmicrobial, nonmammalian haptene, p-arsanilic acid, were labeled with 125I by the lodogen-Bead method. Unilateral, deep thigh infections were created by innoculation with 2 X 10(8) Fisher Immunotype 1 P. aeruginosa. Twenty-four hours later, one of the radiolabeled antibodies was injected intravenously at a dose of 0.25 mg/kg (100-150 microCi). Serial gamma imaging was then carried out beginning at 4 hr and at approximately 24-hr intervals thereafter. Beginning as early as 4 hr postinjection, the area of inflammation could be visualized with either the specific or nonspecific Mab, with the images continuing to intensify until 24-48 hr postinjection. At 48 hr, the contrast between lesion and background with the nonspecific Mab began to fade, while the contrast in the specific Mab-generated images continued to intensify until approximately 192 hr postinjection. Clear-cut differentiation between specific and nonspecific Mab-generated images was possible by 72 hr postinjection. We conclude that specific immune imaging of localized infection with Mab's directed against specific microbial antigens is possible and should be clinically useful. In addition, images created by the localization of immunoglobulin non-specifically at the site of inflammation in the first 24-48 hr postinjection may also provide useful information as to the anatomic location of hidden abscesses.

Animals↗
PubMed1984

Proteins of the cystic fibrosis respiratory tract. Fragmented immunoglobulin G opsonic antibody causing defective opsonophagocytosis.

In the disease cystic fibrosis (CF), pulmonary infection with Pseudomonas aeruginosa is a common clinical complication that determines most morbidity and almost all excess mortality. We postulated that in this disease a defect in Pseudomonas-reactive IgG antibodies may contribute to chronic Pseudomonas infections. Bronchoalveolar lavages were performed upon 13 patients with CF, 7 patients with chronic bronchitis characterized by recurrent Pseudomonas infections, and 4 normal volunteers. The levels of various proteins important to host defenses and proteases were determined; enzyme inhibition studies were performed. CF respiratory immunoglobulin levels were significantly elevated when compared with both normals and patients with chronic bronchitis (P less than 0.05). Albumin and transferrin levels were decreased in the CF lung fluids. CF elastolytic activity was strikingly elevated (means = 6.02 micrograms/mg total protein) and the inhibitory profile suggested such activity resembled a serine-proteinase. Alpha-1-antitrypsin antigenic levels were not altered in CF respiratory fluids. There was a tendency for the lavage IgG to fall as elastase levels rose (r = -0.29). IgG opsonins for two Pseudomonas immunotypes were isolated with affinity chromatography for functional and immunochemical studies. Bacterial phagocytic rates in the presence of these Pseudomonas-reactive IgG opsonins derived from CF lavage fluid were depressed (0.3% uptake/unit time) when compared with similarly titered positive controls (uptake = 1.3%/unit time, P less than 0.001). Additionally, normal pulmonary macrophage intracellular killing of Pseudomonas was severely altered in the presence of opsonins derived from CF respiratory fluids. At some time points, less than 30% of the bacteria were killed. CF IgG opsonins contain a cleavage fragment (100,000 D, 5S sedimentation coefficient) with antigenic determinants similar to the Fab portion of IgG. The presence of such a fragment was inversely correlated with phagocytic functional activity. Intact IgG comprised as little as 18% of the CF lavage fluid specimens. Aliquots of intact human IgG, when mixed with the CF opsonins, augmented Pseudomonas uptake and improved intracellular killing. Conversely, peptide fragments of IgG opsonins, which are proteolytically derived in vitro, duplicated in our system the defect observed with opsonins derived from CF lung fluids; bacterial uptake was inversely related to the concentration of F(ab')2 and to a greater degree, to Fc present in the opsonic mixture. We concluded that IgG respiratory opsonins are fragmented, inhibiting phagocytosis and serving a permissive role in the chronic Pseudomonas pulmonary infection in the disease CF.

Adult↗
PubMed2005

Influence of cystic fibrosis transmembrane conductance regulator on gene expression in response to Pseudomonas aeruginosa infection of human bronchial epithelial cells.

Chronic lung infection by Pseudomonas aeruginosa causes significant morbidity in cystic fibrosis patients initiated by the failure of innate immune responses. We used microarray analysis and real-time PCR to detect transcriptional changes associated with cytokine production in isogenic bronchial epithelial cell lines with either wild-type (WT) or mutant cystic fibrosis transmembrane conductance regulator (CFTR) in response to P. aeruginosa infection. The transcription of four NF-kappaB-regulated cytokine genes was maximal in the presence of WT CFTR: the interleukin-8 (IL-8), IL-6, CXCL1, and intracellular adhesion molecule 1 (ICAM-1) genes. Analysis of protein expression in two cell lines paired for wild-type and mutant CFTR with three P. aeruginosa strains showed IL-6 and IL-8 expressions were consistently enhanced by the presence of WT CFTR in both cell lines with all three strains of P. aeruginosa, although some strains gave small IL-8 increases in cells with mutant CFTR. CXCL1 production showed consistent enhancement in cells with WT CFTR using all three bacterial strains in one cell line, whereas in the other cell line, CXCL1 showed a significant increase in cells with either WT or mutant CFTR. ICAM-1 was unchanged at the protein level in one of the cell lines but did show mild enhancement with WT CFTR in the other cell pair. Inhibitions of NF-kappaB prior to infection indicated differing degrees of dependence on NF-kappaB for production of the cytokines, contingent on the cell line. Cytokine effectors of innate immunity to P. aeruginosa were found to be positively influenced by the presence of WT CFTR, indicating a role in resistance to P. aeruginosa infection.

Bronchi↗
PubMed1991

Unusual presentation of Pseudomonas aeruginosa infections: a review.

Pseudomonas aeruginosa is an opportunistic, gram negative bacillus that causes serious hospital acquired infections. However, it also causes infections with unusual presentations which are acquired in a non-hospital environment. This report will discuss the pathogenesis, clinical manifestations, and therapy of this uncommon infection, such as: 1) Pseudomonas folliculitis: a superficial or deep bacterial infection associated with the use of public hot tubs, whirlpools and swimming pools. 2) Invasive external otitis: an infection that can progress to skull base mostly associated to elderly diabetic patients. It is usually secondary to aural irrigation with contaminated water. 3) Pseudomonas osteomyelitis: an infection usually associated with nail puncture wounds especially if wearing tennis shoes. 4) Toe with infection: mostly associated with individuals using topical antibacterial agents. 5) Green nail syndrome: a non tender paronychia lesion that appears most often in persons whose hands are constantly exposed to water, soaps and detergents or are subject to mechanical trauma. 6) Corneal ulcer keratitis: mostly associated with the use of soft lenses, eye drops, mascara or contaminated whirlpools. This condition may terminate in panophthalmitis. 7) Endocarditis: most commonly associated with intravenous drug addicts.

Corneal Ulcer↗