Starvation selection restores elastase and rhamnolipid production in a Pseudomonas aeruginosa quorum-sensing mutant

The las quorum-sensing system of Pseudomonas aeruginosa controls the expression of elastase and rhamnolipid. We report that starvation can select a mutant producing these virulence factors in spite of a lasR deletion. Expression of the autoinducer synthase gene rhlI was increased in this suppressor mutant, suggesting compensation by the rhl system. These data show that P. aeruginosa can restore elastase and rhamnolipid production in the absence of a functional las quorum-sensing system.     

In vitro efficacy of levofloxacin alone or in combination tested against multi-resistant Pseudomonas aeruginosa strains

PURPOSE: To describe the causes and outcomes of pediatric injuries using the emergency departments (ED) as a surveillance site. METHOD: Prospective, 14-day surveys of all injuries were conducted in the EDs of the two national trauma referral hospitals of Trinidad and Tobago. Data on patient demographics, type, cause, and outcome of injuries were collected. The chi 2 test for significance was used for categorical variables. RESULTS: Pediatric patients (< 20 years) accounted for 41.5% (714/1722) of injury visits. Of these, 62.6% were male and 17.4% were < four years old, 26.2% four to nine years, 31.1% 10 to 14 years, and 25.4% were 15 to 19 years old. Three patients (0.4%) died, 68.6% were discharged, and 31.0% admitted. Intentional injuries accounted for 13.9% of injuries. Of the intentional injuries, the assailant was significantly more likely to be known than not (P < 0.01). The most common causes of all injuries were: falls, 44.4%; blunt objects, 12.3%; sharp objects, 11.8%; motor vehicle (including pedestrians), 7.4%; poison, 3.6%; and burns, 1.7%. Injuries occurring in the home accounted for 46.2%; in school, 25.5%; sports/recreation, 11.1%; and at work, 4.5%. The most common injuries were: lacerations, 30.8%, contusions/abrasions, 26.7%, fractures, 18.8%; and sprains/dislocations, 9.4%. CONCLUSION: Pediatric injuries are a significant cause of morbidity and mortality in this country, accounting for almost one third of injured patients. Because of the low frequency of pediatric injury deaths, ED surveillance may be a more effective means of identifying high risk groups and activities for injuries. Data from EDs may be useful in other developing countries to develop injury prevention programs.     

In vitro activity of polyunsaturated fatty acids on Pseudomonas aeruginosa: relationship to lipid peroxidation

The treatment of patients with deep vein thrombosis and pulmonary embolism with contraindications for a thrombolytic therapy is a therapeutic challenge. We report on a 12 year old patient who was treated for large cell lymphoma according to NHL-BFM 95: Block AA protocol. During his therapy, he developed a thrombosis of his right femoral vein and pulmonary embolism affecting the left segments 4, 5, 8, and 9. Because of cerebral metastasis a fibrinolytic therapy was contraindicated. Therefore, we performed a mechanical thrombectomy using the Amplatz thrombectomy device. The postinterventional scintigraphy showed a markedly improved pulmonary perfusion; dopplersonography 4 months postinterventionally showed a patent right femoral vein.     

In vitro inhibition of the growth of Gardnerella vaginalis by bacteriocins produced by strains of Pseudomonas aeruginosa

BACKGROUND: Pseudomonas aeruginosa with inhibitory capacity in vitro was studied on Gardnerella vaginalis strains. METHODS: Antimicrobial activity was demonstrated by inhibitory halos of bacterial growth on solid media by two methods: crossed streak and agar well diffusion. The inhibitory activity of this substance produced by P. aeruginosa was characterized as bacteriocin by: activity spectrum sensitivity proteolytic enzyme, chloroform, heat, pH, ultraviolet, irradiation effect and molecular weight. RESULTS: Four strains of P. aeruginosa producers of bacteriocins were chosen for this study and contacted with 40 strains of G. vaginalis. The producing strain D inhibited 70% of these G. vaginalis strains. The strains B and C inhibited 55% and 52.5%, respectively. The 3 strains presented a wide rank of action but the strain A had effect on a few strains of G. vaginalis. CONCLUSIONS: This work showed the inhibitory in vitro effect of bacteriocins of P. aeruginosa on strains of G. vaginalis. The results obtained suggest the probable topic application of bacteriocins as an alternative of conventional therapeutic on this infection biological control.     

Production of acyl-homoserine lactone quorum-sensing signals by gram-negative plant-associated bacteria

Many gram-negative bacteria regulate expression of specialized gene sets in response to population density. This regulatory mechanism, called autoinduction or quorum-sensing, is based on the production by the bacteria of a small, diffusible signal molecule called the autoinducer. In the most well-studied systems the autoinducers are N-acylated derivatives of L-homoserine lactone (acyl-HSL). Signal specificity is conferred by the length, and the nature of the substitution at C-3, of the acyl side-chain. We evaluated four acyl-HSL bioreporters, based on tra of Agrobacterium tumefaciens, lux of Vibrio fischeri, las of Pseudomonas aeruginosa, and pigment production by Chromobacterium violaceum, for their ability to detect sets of 3-oxo acyl-HSLs, 3-hydroxy acyl-HSLs, and alkanoyl-HSLs with chain lengths ranging from C4 to C12. The traG::lacZ fusion reporter from the A. tumefaciens Ti plasmid was the single most sensitive and versatile detector of the four. Using this reporter, we screened 106 isolates representing seven genera of bacteria that associate with plants. Most of the Agrobacterium, Rhizobium, and Pantoea isolates and about half of the Erwinia and Pseudomonas isolates gave positive reactions. Only a few isolates of Xanthomonas produced a detectable signal. We characterized the acyl-HSLs produced by a subset of the isolates by thin-layer chromatography. Among the pseudomonads and erwinias, most produced a single dominant activity chromatographing with the properties of N-(3-oxo-hexanoyl)-L-HSL. However, a few of the erwinias, and the P. fluorescens and Ralstonia solanacearum isolates, produced quite different signals, including 3-hydroxy forms, as well as active compounds that chromatographed with properties unlike any of our standards. The few positive xanthomonas, and almost all of the agrobacteria, produced small amounts of a compound with the chromatographic properties of N-(3-oxo-octanoyl)-L-HSL. Members of the genus Rhizobium showed the greatest diversity, with some producing as few as one and others producing as many as seven detectable signals. Several isolates produced extremely nonpolar compounds indicative of very long acyl side-chains. Production of these compounds suggests that quorum-sensing is common as a gene regulatory mechanism among gram-negative plant-associated bacteria.     

In vitro biosynthesis of rabbit blastokinin

Changes of the height of retinal detachments up to 0.1 mm can be visualized by A-scan-ultrasonography; such small changes cannot be ascertained by means of ophthalmoscopy. Based on echooculometric measurements of the maximal height of retinal detachments during the first hours and days after surgery without subretinal drainage, the final success (24 cases) or failure (2 cases) could be predicted 24 hours at latest. Thus in cases of retarded resorption of the subretinal fluid it can be decided by means of echography, wether a reattachment of the retina can be expected or a failure, the cause of which needs early detection.     

In vitro enzyme activation and folded stability of Pseudomonas aeruginosa exotoxin A and its C-terminal peptide

Pseudomonas aeruginosa exotoxin A(ETA) and its C-terminal, enzymatically active fragment (PE40, 375 residues) were studied by high-performance size-exclusion chromatography, steady-state and stopped-flow fluorescence spectroscopy, and circular dichroism spectroscopy. Both proteins have been overexpressed and purified by high-performance liquid chromatography. The effect of various activation conditions (pH, urea, and DTT) on enzymatic activity was studied. Upon enzymatic activation, structural changes induced within both proteins' structures were monitored, and these changes were correlated with concomitant alterations in the catalytic activity of the proteins. The pH optimum of enzymatic activity for both ETA and PE40 was between 7.0 and 8.0, decreasing to nearly zero at acidic (pH 5.0) and basic (pH 11-12) values. Analysis of the pH titration data revealed the presence of two distinct pKa values which implicate a His residue(s) (likely His-440 and -426) and a Tyr or Lys residue (possibly Tyr-481). The identity and possible role of an active site Lys residue is not known. Additionally, a significant increase in the Stokes radii of both proteins was detected when the pH was lowered from 8.0 to 6.0. The enzymatic activity of PE40 was not affected by urea or DTT, and its Stokes radius decreased monotonically with increasing urea concentration in the presence of DTT. In contrast, the enzymatic activity of ETA peaked when the protein was preincubated with 4.0 M urea, and this coincided with a large transition (increase) in the protein's Stokes radius between 3 and 5 M urea. Furthermore, loss of helical secondary structure of both PE40 and ETA commenced at approximately 2 M urea and progressively diminished at higher denaturant concentrations. The unfolding of both proteins in urea (and DTT) was reversible, and the free energies of unfolding were determined by both circular dichroism and fluorescence spectroscopy and were found to be 13.7 +/- 2.9 and 9.8 +/- 3.4 kJ/mol, respectively, for ETA and were 17.8 +/- 6.8 and 7.5 +/- 3.6 kJ/mol, respectively, for PE40. The refolding rate of PE40 was relatively rapid [t 1/2(1) = 27 s, t 1/2(2) = 624 s], which was in stark contrast to the refolding rate of ETA (t 1/2 = several hours). The relative refolding rates of PE40 and ETA help to explain the mechanism of in vitro enzyme activation and assay.     

Biofilms on indwelling urethral catheters produce quorum-sensing signal molecules in situ and in vitro

Acylated homoserine lactones (AHLs) are chemical signals that mediate population density-dependent (quorum-sensing) gene expression in numerous gram-negative bacteria. In this study, gram-negative bacilli isolated from catheters were screened for AHL production by a cross-feeding assay utilizing an AHL-responsive Agrobacterium tumefaciens reporter strain. Positive reactions were obtained from 14 isolates of Pseudomonas aeruginosa; negative or weakly positive reactions were recorded for isolates of five other species. P. aeruginosa biofilms were then produced on catheters in a physical model of the bladder. Sections of colonized all-silicone catheters gave positive reactions for the quorum-sensing signal molecules as did sections that had been cleaned of biofilm and autoclaved. Control sections of unused catheters were negative in the tests. Sections from four of nine catheters that had been freshly removed from patients gave positive reactions for AHLs. Cleaned autoclaved sections of three of these catheters also gave strongly positive reactions for AHLs. These results demonstrate that AHLs are produced by biofilms as they develop on the catheters both in vitro in the model and in vivo in the patient's bladder. They represent the first demonstration of AHL production by biofilms in a clinical setting.     

In vivo effect of growth-inhibitor produced by Pseudomonas aeruginosa isolates and anti-pseudomonal drugs on model infection due to Pseudomonas aeruginosa

Pseudomonas aeruginosa Nos. 1 and 5, each co-existing growth-inhibitor-producing and -nonproducing cells, were used in this study. An equal number of both cells (each 10(8) CFU/mouse) was challenged intraperitoneally to mice, and these cells in the heart blood and kidneys of mice were determined. Furthermore, the effect of piperacillin, ceftazidime and sisomicin on the cell distribution in mice was studied in the model infection due to P. aeruginosa Nos. 1 and 5. As a control experiment both cells of P. aeruginosa No. 1 were each challenged intraperitoneally at a dose of 10(8) CFU/mouse to mice of two groups, but there were no marked differences between the two types in cell counts of the heart blood or kidneys 9 hours after challenge. When a concomitant challenge of both cells (each 10(8) CFU/mouse) was performed in mice, the number of growth-inhibitor-producing cells of the heart blood and kidneys was about 100 times greater than that of the non-producing cells. These in vivo results were well comparable to the previous in vitro results and indicated that the inhibitor affected the invasion of the non-producing bacteria in the body in the model infection due to P. aeruginosa isolates consisting of the two types of cells. Similar results were obtained in mice with the model infection due to P. aeruginosa No. 5. Anti-pseudomonal drugs such as piperacillin (50 mg/mouse) and ceftazidime (50 mg/mouse) and sisomicin (1 mg/mouse) were given intramuscularly to mice infected concomitantly with both cells of P. aeruginosa No. 1.(ABSTRACT TRUNCATED AT 250 WORDS)     

Phosphorylation-independent activity of the response regulators AlgB and AlgR in promoting alginate biosynthesis in mucoid Pseudomonas aeruginosa

Overproduction of the capsular polysaccharide alginate appears to confer a selective advantage for Pseudomonas aeruginosa in the lungs of cystic fibrosis patients. The regulators AlgB and AlgR, which are both required as positive activators in alginate overproduction, have homology with the regulator class of two-component environmental responsive proteins which coordinate gene expression through signal transduction mechanisms. Signal transduction in this class of proteins generally occurs via autophosphorylation of the sensor kinase protein and phosphotransfer from the sensor to a conserved aspartate residue, which is present in the amino terminus of the response regulator. Recently, kinB was identified downstream of algB and was shown to encode the cognate histidine protein kinase that efficiently phosphorylates AlgB. However, we show here that a null mutation in kinB in a mucoid cystic fibrosis isolate, P. aeruginosa FRD1, did not block alginate production. The role of the conserved aspartate residue in the phosphorylation of AlgB was examined. The predicted phosphorylation site of AlgB (D59) was mutated to asparagine (N), and a derivative of an AlgB lacking the entire amino-terminal phosphorylation domain (AlgB delta1-145) was constructed. A hexahistidine tag was included at the amino terminus of the wild-type (H-AlgB), H-AlgB delta1-145, and mutant (H-AlgB.59N) AlgB proteins. These derivatives were purified by Ni2+ affinity chromatography and examined for in vitro phosphorylation by the purified sensor kinase protein, KinB. The results indicated that while KinB efficiently phosphorylated H-AlgB, no phosphorylation of H-AlgB delta1-145 or H-AlgB.D59N was apparent. An allelic exchange system was developed to transfer mutant algB alleles onto the chromosome of a P. aeruginosa algB mutant to examine the effect on alginate production. Despite the defect in AlgB phosphorylation, P. aeruginosa strains expressing AlgB.D59N or H-AlgB delta1-145 remained mucoid. The roles of the conserved aspartate residues in the phosphorylation of AlgR were also examined. As seen with AlgB, mutations in the predicted phosphorylation site of AlgR (AlgR.D54N and AlgR.D85N) did not affect alginate production. These results indicate that in vivo phosphorylation of AlgB and AlgR are not required for their roles in alginate production. Thus, the mechanism by which these response regulators activate alginate genes in mucoid P. aeruginosa appears not to be mediated by conventional phosphorylation-dependent signal transduction.     

Penicillin-resistant mechanisms in Pseudomonas aeruginosa: binding of penicillin to Pseudomonas aeruginosa KM 338

A comparison of the binding of radioactive penicillin G to whole cells and the membrane fraction derived from Pseudomonas aeruginosa KM 338 was made. This organism has intrinsic resistance to penicillin. The binding to the membrane fraction which catalyzed peptidoglycan synthesis followed saturation type kinetics and saturation was achieved at approximately 2 nmol of penicillin G per ml, whereas binding to the whole cells was entirely of the nonsaturation type. The binding of carbenicillin to the membrane fraction was determined by competition between radioactive penicillin G and unlabeled carbenicillin for the binding sites. It was bound at the same sites in almost the same manner. When whole cells were pretreated with high concentration of unlabeled penicillin G or carbenicillin, the subsequent binding of radioactive penicillin G to the membrane fraction from carbenicillin-treated cells was entirely nonspecific, but with penicillin G-pretreated cells it was still specific. There was apparently specific binding of radioactive penicillin G to ethylenediaminetetraacetate-treated cells. P. aeruginosa KM 338 had an extremely low activity of beta-lactamase compared with other enzyme-producing organisms. This enzyme from P. aeruginosa KM 338 was of the cephalosporinase type. These data indicate that penicillin resistance of P. aeruginosa KM 338 may be a consequence of the development of a permeability barrier which prevents the antibiotic from reaching its sites of action in the cytoplasmic membrane.     

Heterogeneity of the lipopolysaccharide from Pseudomonas aeruginosa

Lipopolysaccharide isolated from pseudomonas aeruginosa PAC1 and its phage-resistant mutant was degraded by mild acid hydrolysis into lipid A and three major polysaccharide-containing fractions which were separated on Sephadex G-75. The low-molecular-weight fraction contained glucose, rhamnose, heptose, galactosamine, alanine and phosphate. The higher-molecular-weight fractions consisted mainly of glucose, rhamnose and glucosamine together with amino compounds. Alkaline degradation of the lipopolysaccharide produced at least four different species each of which contained a low-molecular-weight polysaccharide similar if not identical to that produced by acid hydrolysis. Under certain growth conditions an abnormal lipopolysaccharide was produced which was defective in the low-molecular-weight polysaccharide and contained mainly high-molecular-weight material. Strains of different serotype yielded lipopolysaccharides which also exhibited heterogeneity but contained a low-molecular-weight polysaccharide similar to that obtained from strain PAC1 and PAC1R. It is suggested that each strain of P. aeruginosa may produce several lipopolysaccharides each containing a polysaccharide common to all. The relative proportions of the various lipopolysaccharides may be changed by growth conditions.     

In vitro expression of n-cadherin adhesion molecule during early cardiac morphogenesis

The aim of the present study was to investigate, "in vitro", the degree of organogenetic potentiality of the cells of the cardiogenic area during the early developmental stages of the chick embryo. Embryos from between the end of the presomitic stage to the 8 somite stage were studied. The subcephalic fold was cultured in liquid medium for up to 7 days. After 24 hs of culturing, an extended migration ring was observed. In the explants, from 3 somite stage, onwards, beating masses were noted, the shape and size of which suggested a vascular-like structure. Sections of the cultures were processed for the detection of the N-Cadherin adhesion molecule. The observations stated that the diffusion and intensity of expression of this receptor is related to the stage od development of the embryo. Cultures from the presomitic stage to 3 somite stage did not express the molecule. Instead, expression took place in those cultures of embryos at the 3 somite stage, onwards. In the cultures to which the antiserum against N-Cadherin had been to the medium, the formation of vascular-like structures was affected. The changes depended on the age of the embryos. These observations suggest that the expression of the N-Cadherin is related to the potentiality of the presumptive myocardic cells to organize themselves, at least "in vitro", to form a well-defined tridimensional structure. The expression of the adhesion molecule and the potentiality of the cells to build tubular structures were transient features, "in vitro" in our cultures. This suggests that "in vivo" the expression of the N-Cadherin must be aided by factors which, at present, are unidentified.     

In vitro biosynthesis of a decasaccharide prototype of multiply branched polylactosaminoglycan backbones

Multiply branched polylactosaminoglycans are expressed in glycoproteins and glycolipids of many cells. Interest in their biology stems from their abundant expression in early embryonal cells and from their ability to carry multiple lectin-binding determinants, which makes them prominent ligands and antagonists of cell adhesion proteins. A prototype of their backbones is represented by the decasaccharide LacNAc beta1-3'(LacNAc beta1-6')LacNAc beta1-3'(LacNAc beta1-6')LacNAc (5), where LacNAc is the disaccharide Gal beta1-4GlcNAc. Here, we describe in vitro biosynthesis of glycan 5. Incubation of the linear hexasaccharide LacNAc beta1-3'LacNAc beta1-3'LacNAc (1) with UDP-GlcNAc and alpha midchain beta1,6-GlcNAc transferase activity (GlcNAc to Gal), present in rat serum [Gu, J., Nishikawa, A., Fujii, S., Gasa, S., & Taniguchi, N. (1992) J. Biol. Chem. 267, 2994-2999], gave the doubly branched octasaccharide LacNAc beta1-3'(GlcNAc beta1-6')LacNAc beta1-3'(GlcNAc beta1-6')LacNAc (4). The latter was converted to 5 by enzymatic beta1,4-galactosylation. In the initial branching reaction of 1, two isomeric heptasaccharide intermediates, LacNAc beta1-3'LacNAc beta1-3'(GlcNAc beta1-6')LacNAc (2) and LacNAc beta1-3'(GlcNAc beta1-6')LacNAc beta1-3'LacNAc (3), were formed first at comparable rates. Later, both intermediates were converted to 4, revealing two distinct pathways of the reaction: 1 --> 2 --> 4 and 1 --> 3 --> 4. These data suggest that, regardless of their chain length, linear polylactosamines similar to 1 contain potential branching sites at each of the internal galactoses. The enzyme-binding epitope of 1 is probably LacNAc beta1-3'LacNAc, because the trisaccharides GlcNAc beta1-3'LacNAc and LacNAc beta1-3Gal as well as the tetrasaccharide GlcNAc beta1-3'LacNAc beta1-3Gal were poor acceptors, while LacNAc beta1-3'LacNAc was a good one. Midchain beta1,6-GlcNAc transferase activities present in serum of several mammalian species, including man, resembled closely the rat serum activity in their mode of action and in their acceptor specificity. We suggest that analogous membrane-bound Golgi enzymes are involved in the biosynthesis of multiply branched polylactosamines in vivo.     

Sensitivity testing of ciprofloxacin for Pseudomonas aeruginosa

The presence and distribution of the most important highly repetitive DNA sequences of rye in cultivated and wild species of the genus Secale were investigated using fluorescence in situ hybridization. Accurate identification of individual chromosomes in the most commonly recognized species or subspecies of the genus Secale (S. cereale, S. ancestrale, S. segetale, S. afghanicum, S. dighoricum, S. montanum, S. montanum ssp. kuprijanovii, S. africanum, S. anatolicum, S. vavilovii, and S. silvestre) was achieved using three highly repetitive rye DNA sequences (probes pSc119.2, pSc74, and pSc34) and the 5S ribosomal DNA sequence pTa794. It is difficult to superimpose trends in the complexity of repetitive DNA during the evolution of the genus on conclusions from other cytogenetic and morphological assays. However, there are two clear groups. The first comprises the self-pollinated annuals S. silvestre and S. vavilovii that have few repeated nucleotide sequences of the main families of 120 and 480 bp. The second group presents amplification and interstitialization of the repeated nucleotide sequences and includes the perennials S. montanum, S. anatolicum, S. africanum, and S. kuprijanovii, as well as the annual and open-pollinated species S. cereale and its related weedy forms. The appearance of a new locus for 5S rRNA in S. cereale and S. ancestrale suggests that cultivated ryes evolved from this wild weedy species.     

Surface action of gentamicin on Pseudomonas aeruginosa

The mode of action of gentamicin has traditionally been considered to be at the 30S ribosomal level. However, the inhibition of bacterial protein synthesis alone appears to be insufficient to entirely explain the bactericidal effects. Bacteriolysis is also mediated through perturbation of the cell surface by gentamicin (J.L. Kadurugamuwa, J.S. Lam, and T.J. Beveridge, Antimicrob. Agents Chemother. 37:715-721, 1993). In order to separate the surface effect from protein synthesis in Pseudomonas aeruginosa PAO1, we chemically conjugated bovine serum albumin (BSA) to gentamicin, making the antibiotic too large to penetrate through the cell envelope to interact with the ribosomes of the cytoplasm. Furthermore, this BSA-gentamicin conjugate was also used to coat colloidal gold particles as a probe for electron microscopy to study the surface effect during antibiotic exposure. High-performance liquid chromatography confirmed the conjugation of the protein to the antibiotic. The conjugated gentamicin and BSA retained bactericidal activity and inhibited protein synthesis on isolated ribosomes in vitro but not on intact cells in vivo because of its exclusion from the cytoplasm. When reacted against the bacteria, numerous gentamicin-BSA-gold particles were clearly seen on the cell surfaces of whole mounts and thin sections of cells, while the cytoplasm was devoid of such particles. Disruption of the cell envelope was also observed since gentamicin-BSA and gentamicin-BSA-gold destabilized the outer membrane, evolved outer membrane blebs and vesicles, and formed holes in the cell surface. The morphological evidence suggests that the initial binding of the antibiotic disrupts the packing order of lipopolysaccharide of the outer membrane, which ultimately forms holes in the cell envelope and can lead to cell lysis. It is apparent that gentamicin has two potentially lethal effects on gram-negative cells, that resulting from inhibition of protein synthesis and that resulting from surface perturbation; the two effects in concert make aminoglycoside drugs particularly effective antibiotics.     

Treatment of Pseudomonas aeruginosa infections with pyocines

DNA/cell distributions were recorded by automated cytofluorometry (=pulse cytophotometry) in bone-marrow aspirates of leukaemia and lymphosarcoma patients subjected to chemotherapy. In most cases, early perturbations in DNA/cell histographs were observed, characteristically reflecting the known mode of action of the drugs. These changes in general preceded the clinical observation of drug response. In a series of 23 measurements in 19 patients, a positive correlation between early cytophotometric changes and clinical effects of chemotherapy was observed in 17 patients. Five patients were negative for both cytophotometric and clinical reactions and one patient was probably false-positive. The validity of the assay for early detection of drug resistance in acute leukaemia and related diseases is discussed.     

Hydrophobic properties of Pseudomonas aeruginosa strains]

Hydrophobic properties are considered as a factor enhancing the adhesion of bacteria to tissue cells. The strains of P. aeruginosa isolated from patients with urinary tract infections (UTI), from feces and soil were investigated. It shows that over 50% strains isolated from UTI had hydrophobic cell surface. Most of all strain investigated (67.9%) is characterized by hydrophobicity what probably favours their pathogenicity.