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PubMed1994

Macrorestriction analysis of Pseudomonas aeruginosa in colonized burn patients.

The colonization of hospitalized patients by Pseudomonas aeruginosa at an intensive care unit for burn victims was studied over a one-year period. A total of 231 isolates from 12 patients were analyzed by macrorestriction analysis. The results revealed that most patients were infected with only one to three different strains. In several patients Pseudomonas aeruginosa isolates of the same clonal lineage exhibited considerable differences in their macrorestriction fragment pattern. Digestion with further restriction enzymes, however, allowed differentiation between clonal variants due to a high genetic drift and superinfection with a different Pseudomonas aeruginosa strain. Isolates of the same clonal lineage could be isolated from several patients as well as from the patients' environment. Notably, Pseudomonas aeruginosa could be isolated from sedimentation plates. Thus, patients may have been extensively cross-infected on the ward. These data underline the importance of strict infection control measures and of regular surveillance for Pseudomonas aeruginosa by an appropriate typing method, i.e. one that can differentiate strains with high genomic variability.

Bacterial Typing Techniques↗

PubMed1986

Use of ciprofloxacin in the treatment of Pseudomonas aeruginosa infections.

The therapeutic efficacy and safety of ciprofloxacin was studied in 30 patients with Pseudomonas aeruginosa infections. In 20 patients ciprofloxacin was given alone and in 10 patients (including 8 compromised hosts) in combination with an aminoglycoside (9) or azlocillin (1). Ciprofloxacin was given in doses of 500 mg orally or 200-300 mg i.v. every 12 h. In patients receiving only ciprofloxacin clinical cure with eradication of bacteria was obtained in 15 patients (75%) with infections of bone and joint (6), skin and soft tissue (4), lung (2), middle ear (2) and CSF (1). Two patients with lymphoma and Pseudomonas aeruginosa pneumonia died. In patients receiving combination therapy a definite therapeutic success was achieved in four (40%). Three patients with Pseudomonas aeruginosa septicemia died. In seven patients nine bacterial strains with decreasing susceptibility of ciprofloxacin (increase in MIC from less than or equal to 0.5 micrograms/ml to 2-16 micrograms/ml) were selected (6 Pseudomonas aeruginosa, 1 Enterobacter cloacae, 1 Serratia marcescens, 1 Staphylococcus aureus). Ciprofloxacin was well tolerated. This new quinolone seems to be suitable for single drug treatment of Pseudomonas aeruginosa infections in patients with normal host defense mechanisms, while its therapeutic potential in compromised hosts requires further evaluation.

Administration, Oral↗

PubMed1999

Pseudomonas aeruginosa bacteremia in patients infected with human immunodeficiency virus type 1.

A prospective analysis of 43 episodes of Pseudomonas aeruginosa bacteremia in HIV-1-infected subjects was performed and the results compared with the incidence and outcome of Pseudomonas aeruginosa bacteremia in other high-risk patients, such as transplant recipients, leukemia patients, or patients hospitalized in the intensive care unit. The incidence of bacteremia/fungemia as a whole and of gram-negative and Pseudomonas aeruginosa bacteremia in particular was greater in HIV-1-infected subjects than in the unselected general population admitted. In contrast, the incidence of Pseudomonas aeruginosa bacteremia in HIV-1-infected patients did not differ from that in patients with other high-risk conditions. In patients with HIV-1 infection, independent risk factors for presenting Pseudomonas aeruginosa bacteremia were nosocomial origin (OR, 2.7; 95% CI, 1.3-5.7), neutropenia (OR, 2.7; 95% CI, 1.07-6.8), previous treatment with cephalosporins (OR, 3.6; 95% CI, 1.1-11.6), and a CD4+ cell count lower than 50 cells/mm3 (OR, 3.1; 95% CI, 1.7-8.6). Primary bacteremia and pneumonia were the most common forms of presentation. Fourteen (33%) patients died as a consequence of the bacteremia. The presence of severe sepsis (OR, 17.5; 95% CI, 3.2-68) and the institution of inappropriate definitive antibiotic therapy (OR, 2.7; 95% CI, 1.1-13) were independently associated with a poor outcome. One year after the development of bacteremia, only eight (19%) patients remained alive.

AIDS-Related Opportunistic Infections↗

PubMed1976

Pseudomonas bacteremia. Review of 108 cases.

The current circumstances associated with Pseudomonas aeruginosa bacteremia are reviewed in 108 episodes to assess the impact of new antimicrobial drugs on this infection. Since 1961, Pseudomonas bacteremia has apparently become more frequent with proportional increases in middle-aged patients. The respiratory tract has become the major source of infection. Clinical features are not characteristic, but infected patients are almost uniformly severely ill before blood stream invasion occurs. The use of gentamicin, carbenicillin and colistin has not changed the outcome of Pseudomonas bacteremia. Although better than no antimicrobial treatment, these drugs cannot be shown to be superior to any other available antibiotics. A reassessment is needed to evaluate the relationship between the in vitro action and the effectiveness of antibiotics in the treatment of Pseudomonas infection and the use of gentamicin, carbenicillin and colistin in these bacteremias. In view of the poor results with antibiotics, investigation into immunologic prophylaxis and therapy is needed. At the present time, control of the patients' underlying disease contributes most towards assuring survival with Pseudomonas bacteremia.

Anti-Bacterial Agents↗

PubMed1984

Protective activity of an intravenous immune globulin (human) enriched in antibody against lipopolysaccharide antigens of Pseudomonas aeruginosa.

Human plasmas containing naturally high levels of immunoglobulin G (IgG) to lipopolysaccharide antigens of Pseudomonas aeruginosa immunotypes 1, 2, 4, and 6 were identified by an enzyme-linked immunosorbent assay. The high titered plasmas were collected, pooled, and fractionated. Cohn fraction II IgG was prepared for intravenous infusion. The antibody titers in the hyperimmune intravenous immunoglobulin preparation were approximately fivefold higher against P. aeruginosa immunotypes 1, 2, 4, 5, and 6 and approximately twofold higher against immunotypes 3 and 7 than conventional intravenous immunoglobulin G. When tested for prophylaxis in burned mice, the protective doses 50 percent of Pseudomonas-intravenous immunoglobulin G were approximately fourfold less effective against immunotypes 1, 2, 4, and 7 and International Antigenic Typing System Serotypes (IATS), 8 (= immunotype 6) than conventional intravenous immunoglobulin G. Against immunotype 3 and 5, IATS 13, 15, and 16, both immunoglobulin preparations afforded similar levels of protection. In burned mice challenged with immunotypes 1 and 2 and not treated until 18 hours after infection, Pseudomonas-intravenous immunoglobulin G and tobramycin had synergistic activity in preventing death. Pseudomonas-intravenous immunoglobulin G also afforded significant protection to immunosuppressed mice challenged with immunotype 1. These data suggest that Pseudomonas-intravenous immunoglobulin G may be useful in prevention or treatment of P. aeruginosa infections in man.

Animals↗

PubMed1986

Antibiotic resistance of Pseudomonas species.

Pseudomonas species are highly versatile organisms with genetic and physiologic capabilities that allow them to flourish in environments hostile to most pathogenic bacteria. Within the lung of the patient with cystic fibrosis, exposed to a number of antimicrobial agents, highly resistant clones of Pseudomonas are selected. These may have acquired plasmid-mediated genes encoding a variety of beta-lactamases or aminoglycoside modifying enzymes. Frequently these resistance determinants are on transposable elements, facilitating their dissemination among the population of bacteria. Mutations in chromosomal genes can also occur, resulting in constitutive expression of normally repressed enzymes, such as the chromosomal cephalosporinase of Pseudomonas aeruginosa or Pseudomonas cepacia. These enzymes may confer resistance to the expanded-spectrum beta-lactam drugs. Decreased cellular permeability to the beta-lactams and the aminoglycosides also results in clinically significant antibiotic resistance. The development of new drugs with anti-Pseudomonas activity, beta-lactam agents and the quinolones, has improved the potential for effective chemotherapy but has not surpassed the potential of the organisms to develop resistance.

Aminoglycosides↗

PubMed2004

[Pseudomonas eccrine hidradenitis in a child revealing acute lymphoblastic leukemia].

INTRODUCTION: We report the case of a Pseudomonas (P.) aeruginosa eccrine hidradenitis in a child, or a "Pseudomonas Hot Foot Syndrome", revealing an acute lymphoblastic leukemia. OBSERVATION: A 10 year-old girl consulted for the sudden onset of painful and necrotic palmoplantar nodules in a context of fever and shivering. Histology of a cutaneous biopsy found necrosis of the eccrine glands and, on culture, P. aeruginosa. The blood count revealed pancytopenia and the myelogram acute lymphoblastic leukemia. All the hemocultures and other microbiological samples were negative. The cutaneous signs had appeared 48 hours after bathing in an aquatic amusement park. Diagnosis of Pseudomonas eccrine hidradenitis, or "Pseudomonas Hot Foot Syndrome" was retained, although the local sanitary authorities were not able to demonstrate P. aeruginosa contamination of the water in the park. COMMENTS: Lesions evoking juvenile Pseudomonas aeruginosa eccrine hidradenitis without obvious traumatic factor must lead to the search for P. aeruginosa contamination from water and the subsequent sanitary and epidemiological consequences. Furthermore, severe P. aeruginosa cutaneous infections in children must also lead to the search for an underlying immunosuppression and notably an acute leukemic process.

Child↗

PubMed1996

Inhibition of proteases in Pseudomonas otitis media in chinchillas.

The treatment of chronic suppurative otitis media caused by Pseudomonas aeruginosa remains a challenging problem. The virulence of Pseudomonas is related to its secretion of two matrix metalloproteinases, alkaline protease and elastase. This experiment examines the effects of a synthetic inhibitor of matrix metalloproteinases GM 6001, or N-(2(R)-2(hydroxyamido carbonylmethyl)-4-methylpentanoyl)-L-tryptophane methylamide), in a chinchilla Pseudomonas otitis media model. Thirty chinchillas underwent bilateral subtotal tympanic membrane perforations. Twenty-four chinchillas underwent bilateral middle ear inoculation with P. aeruginosa. Chinchillas were divided into four groups of six animals after the establishment of otitis media. Animals in one group were controls; the other three groups received either gentamicin, GM 6001, or gentamicin plus GM 6001 into the external auditory canal three times daily for 4 weeks. Clearance of Pseudomonas infection occurred in three ears of three animals, all in gentamicin groups, with or without GM 6001. Otorrhea (p = 0.0014) and external canal erythema (p = 0.025) were mild in the two gentamicin groups and moderate in the GM 6001 group when compared with bacterial controls. Animals in the GM 6001 group had the highest survival rate, less severe facial paralysis, and less vestibular toxicity than the gentamicin, gentamicin plus GM 6001, or control groups, although these differences were not statistically significant. This pilot study showed encouraging results for a role of ototopical protease inhibitors in the treatment of Pseudomonas otitis media.

Animals↗

PubMed2003

Genetic characterization of the styrene lower catabolic pathway of Pseudomonas sp. strain Y2.

Pseudomonas sp. strain Y2 is a styrene-degrading bacterium, which initiates the catabolism of this compound via its transformation into phenylacetate by the sequential oxidation of the vinyl side chain. The styrene upper catabolic gene cluster (sty genes) had been localized in a 9.2-kb chromosomal region. This report describes the isolation, sequencing and analysis of an adjacent 20.5-kb chromosomal region that contains the genes of the styrene lower degradative pathway (paa genes), which are involved in the transformation of phenylacetate into aliphatic compounds that can enter the Krebs cycle. Hence, Pseudomonas sp. strain Y2 becomes the first microorganism whose entire styrene catabolic cluster has been completely characterized. Analysis of the paa gene cluster has revealed the presence of 17 open reading frames as well as gene duplications and gene reorganizations that are absent in other phenylacetate catabolic clusters described so far. The functionality of these genes has been proved by means of both complementation experiments on Pseudomonas putida mutants and in vitro enzymatic assays. Moreover, a DNA cassette encoding the whole styrene lower pathway has been constructed and has been used to expand the ability of Pseudomonas strains to degrade phenylacetic acid. For the first time, two functional phenylacetate-CoA ligases have been identified in an aerobic phenylacetic acid degradation pathway. Although the upper and lower styrene catabolic clusters are adjacent in the Pseudomonas sp. strain Y2 chromosome, their particular base composition and codon usage suggest a distinct evolutionary history.

Base Sequence↗

PubMed2000

Characterization of T cell clones derived from lymph nodes and lungs of Pseudomonas aeruginosa-susceptible and resistant mice following immunization with heat-killed bacteria.

Pseudomonas aeruginosa-resistant BALB/c and susceptible C57Bl/6 (B6) mice were immunized with heat-killed Pseudomonas either in the foot pad or via the trachea, and panels of Pseudomonas-specific T cell clones were developed from lymph nodes and lungs. All clones from either strain, whether of lymph node or lung origin, were CD3+CD4+CD8-TCRalphabeta+. The efficacy of cloning from lymph node cells was comparable between BALB/c and B6 mice. All lymph node BALB/c clones proliferated in response to Pseudomonas antigen in a dose-dependent manner, and this response was MHC class II-restricted. Vigorous proliferation by a considerable proportion of B6 T cell clones occurred in the absence of specific antigen. Lymph node clones from either strain could be categorized as either Th1 or Th0 on the basis of interferon-gamma (IFN-gamma)/IL-4 production. In either mouse strain the efficacy of cloning from lung tissue was substantially lower than from lymph nodes, but the efficacy of cloning from BALB/c compared with B6 lungs was higher. Four lung T cell clones from BALB/c and two from B6 mice were expanded for further analyses, and an interstrain difference was observed in cytokine production. Both B6 lung T cell clones were Th1-like and produced IFN-gamma but not IL-4 and IL-10, whereas four BALB/c lung T cell clones were Th2-like and produced IL-4 and IL-10 but not IFN-gamma. These observations suggest that differences in the CD4+ Th response in the lung may contribute to differences among inbred mouse strains in the level of resistance to bronchopulmonary Pseudomonas infection.

Animals↗

PubMed1991

Enoxacin therapy for experimental pseudomonas keratitis.

Pseudomonas keratitis is difficult to treat and aminoglycosides, the drugs now used for this purpose, are not always effective. New drugs are thus needed to cure gentamicin resistant pseudomonas ocular infections. Enoxacin, a new quinolone, active in vitro against Pseudomonas aeruginosa, was evaluated in experimental ulcerative keratitis produced by a gentamicin resistant isolate of Pseudomonas aeruginosa in rabbits. Our study shows that enoxacin eye drops eliminated pseudomonas infection of the cornea and achieved therapeutic levels in the aqueous humor. Supplementation with parenterally given enoxacin augmented this effect. Enoxacin did not penetrate the vitreous. Enoxacin eye drops may be evaluated for their clinical usefulness in case of keratitis caused by Gram-negative bacilli.

Animals↗

PubMed1980

Long-term Pseudomonas colonization in spinal cord injury patients.

In a previous study, patients with spinal cord injuries were observed to have a high incidence of colonizaion of the perineum, rectum, and urethra with Pseudomonas. In the current report, 10 men and 10 women with spinal cord injury were studied prospectively during their stay in hospital between June-Dec. 1977 (men) and Jan.-Nov. 1978 (women). Colonization seen in men (9/10 men: 14 episodes) was significantly more frequent than colonization in women (3/10 women: 5 episodes). Pseudomonas persisted in two or three sites for up to 105 days (mean 47 days) and serotyping showed that colonization was constant with one or two serotypes. Initial colonization occurred most frequently in the perineum and/or rectum. Colonization of the perineum was significantly more frequent than colonization of the rectum or urethra in men. Fifteen episodes of bacteriuria occurred only after (or with) colonization of perineum, urethra, and rectum. Rates of urethral colonization with Pseudomonas were higher in patients with external condom catheters than patients not using the external codon catheter. Urethral and perineal colonization usually resulted in colonization of the drainage bags even when these patients did not have significant bacteriuria. These drainage bags may be an important potential source of Pseudomonas for nosocomial infection. These studies indicate that Pseudomonas infections of the urinary tract may be prevented if acquisition of this pathogen in the perineum and/or rectum can be avoided.

Adolescent↗

PubMed1991

Novel plasmid vectors for gene cloning in Pseudomonas.

Novel host-vector systems have been developed for gene cloning in the metabolically versatile bacterial genus Pseudomonas. We found that a new Pseudomonas strain, Pseudomonas flavida IF-4, isolated from soil, carried two small cryptic plasmids, named pNI10 and pNI20. They were multi-copy, but not self-transmissible, and the genome size was 3.7 kb for pNI10 and 2.9 kb for pNI20. Several types of cloning vectors containing a kanamycin or streptomycin resistance (Kmr or Smr) gene were constructed from pNI10 and pNI20. These plasmid vectors were efficiently transformed into several strains of Pseudomonas at a frequency up to 4 x 10(5) transformants per 1 microgram plasmid DNA by the usual competent cell method. The vectors derived from pNI10 replicated not only in Pseudomonas but also in some other Gram-negative enteric bacteria such as Escherichia coli, Enterobacter aerogenes, and Proteus mirabilis.

Blotting, Southern↗

PubMed2006

Pseudomonas simiae sp. nov., isolated from clinical specimens from monkeys (Callithrix geoffroyi).

An unusual Gram-negative, catalase- and oxidase-positive, rod-shaped bacterium isolated from different clinical samples from two monkeys (Callithrix geoffroyi) was characterized by phenotypic and molecular genetic methods. The micro-organism was tentatively identified as a Pseudomonas species on the basis of the results of cellular morphological and biochemical tests. Fatty acid studies confirmed this generic placement and comparative 16S rRNA gene sequencing studies demonstrated that the unknown isolates were phylogenetically closely related to each other (100% sequence similarity) and were part of the 'Pseudomonas fluorescens intrageneric cluster'. The novel bacterium, however, was distinguished from other phylogenetically related species of Pseudomonas by DNA-DNA hybridization studies and biochemical tests. On the basis of both phenotypic and phylogenetic findings, it is proposed that the novel Pseudomonas isolates are classified as Pseudomonas simiae sp. nov. The type strain of P. simiae is OLiT (=CCUG 50988T=CECT 7078T).

Animals↗

PubMed2005

Extracellular protease activity of different Pseudomonas strains: dependence of proteolytic activity on culture conditions.

AIMS: This study investigated the effect of growth conditions on proteolytic activity of a Pseudomonas strain, named Pseudomonas sp. LBSA1, isolated from bulk raw milk. It was compared with three Pseudomonas chlororaphis and one Pseudomonas fluorescens strain from culture collections. METHODS AND RESULTS: Bacteriae were grown in a minimal salt medium. For all the strains, addition of 1% (v/v) skim milk to the growth medium was sufficient to induce protease production in 48-h culture. Addition of 1 mmol l(-1) calcium chloride permitted the detection of proteolytic activity of four strains in 48-h cultures but not for Pseudomonas sp. LBSA1. The five strains presented two patterns of proteolytic activity when grown in the minimal salt medium supplemented with 2% (v/v) skim milk at various temperatures for 48 h. Two electrophoretic protease patterns were also obtained from the zymogram of extracellular medium for the five strains. CONCLUSIONS: The growth conditions permitting protease production are variable and do not depend on the genus of the producing strain. SIGNIFICANCE AND IMPACT OF THE STUDY: For the first time a study on proteolytic activity of P. chlororaphis strains is reported. Among the tested criteria, zymograms of extracellular medium were the only ones that permitted distinguishing the P. chlororaphis strains from the P. fluorescens strain.

Animals↗

PubMed1976

Effect of cyclophosphamide on the immune response to Pseudomonas aeruginosa in mice.

Natural resistance in mice to Pseudomonas aeruginosa was decreased 10-fold with a single dose of 300 mg of cyclophosphamide (CY) per kg intraperitoneally. Mice were resistant to infection when immunized actively with Pseudomonas vaccine or passively with Pseudomonas immune serum before receiving CY. Syngeneic spleen, thymus and/or bone marrow cells were transfused into CY-treated recipient mice. Protective anti-Pseudomonas antibody was elicited in the recipient mice when they were vaccinated 1 day after receiving normal spleen cells and challenged 8 days after vaccination. When 1.6 X 10(7) normal thymus and bone marrow cells were infused before vaccination, 69% of the recipients of both cell preparations responded serologically compared with 15 and 27% of those receiving either thymus or bone marrow cells, respectively. CY-treated thymus or bone marrow cell recipients were resistant to Pseudomonas infection when 6 X 10(7) of either cell population was transfused.

Animals↗

PubMed2003

Interleukin-18 impairs the pulmonary host response to Pseudomonas aeruginosa.

Interleukin-18 (IL-18) is a potent cytokine with many different proinflammatory activities. To study the role of IL-18 in the pathogenesis of Pseudomonas pneumonia, IL-18-deficient (IL-18(-/-)) and wild-type mice were intranasally inoculated with Pseudomonas aeruginosa. IL-18 deficiency was associated with reduced outgrowth of Pseudomonas in the lungs and diminished dissemination of the infection. In addition, pulmonary inflammation (histopathology) and levels of tumor necrosis factor alpha, IL-6, and macrophage inflammatory protein-2 in lungs and plasma were lower in IL-18(-/-) mice. Consistent with results obtained for IL-18(-/-) mice, treatment of wild-type mice with a neutralizing IL-18 binding protein-immunoglobulin G Fc fusion construct also attenuated outgrowth of Pseudomonas compared with that for mice treated with a control protein. These results demonstrate that the presence of endogenous IL-18 activity facilitates inflammatory responses in the lung during Pseudomonas pneumonia, concurrently impairing bacterial clearance.

Animals↗

PubMed2004

MorA defines a new class of regulators affecting flagellar development and biofilm formation in diverse Pseudomonas species.

Assembly of bacterial flagella is developmentally important during both planktonic cell growth and biofilm formation. Flagellar biogenesis is complex, requiring coordinated expression of over 40 genes, and normally commences during the log-to-stationary transition phase. We describe here a novel membrane-localized regulator, MorA, that controls the timing of flagellar development and affects motility, chemotaxis, and biofilm formation in Pseudomonas putida. MorA is conserved among diverse Pseudomonas species, and homologues are present in all Pseudomonas genomes sequenced thus far. In P. putida, the absence of MorA derepresses flagellar development, which leads to constitutive formation of flagella in the mutant cells in all growth phases. In Pseudomonas aeruginosa, the absence of MorA led to a reduction in biofilm formation. However, unlike the motility of P. putida, the motility of the P. aeruginosa mutants was unaffected. Our data illustrate a novel developmentally regulated sensory and signaling pathway for several properties required for virulence and ecological fitness of Pseudomonas species.

Amino Acid Sequence↗