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PubMed2004

Azithromycin blocks neutrophil recruitment in Pseudomonas endobronchial infection.

Macrolides exert their effects on the host by modulation of immune responses. In this study, we assessed the therapeutic efficacy of azithromycin in a murine model of mucoid Pseudomonas aeruginosa endobronchial infection. The clearance of Pseudomonas from the airway of mice treated with the macrolide azithromycin was not different than untreated mice challenged with Pseudomonas beads. However, the azithromycin-treated mice showed a remarkable reduction in lung cellular infiltrate in response to Pseudomonas beads, as compared with untreated mice. This effect was associated with significant decreases in lung levels of tumor necrosis factor-alpha and keratinocyte-derived chemokine in azithromycin-treated mice compared with untreated mice. Furthermore, there was a significant reduction in the response of both mouse and human neutrophils to chemokine-dependent and -independent chemoattractants when studied in vitro. Inhibition of chemotaxis correlated with azithromycin-mediated inhibition of extracellular signal-regulated kinase-1 and -2 activation. This study indicates that the azithromycin treatment in vivo results in significant reduction in airway-specific inflammation, which occurs in part by inhibition of neutrophil recruitment to the lung through reduction in proinflammatory cytokine expression and inhibition of neutrophil migration via the extracellular signal-regulated kinase-1 and -2 signal transduction pathway.

Animals↗

PubMed2003

Pseudomonas aeruginosa adherence to human basement membrane collagen in vitro.

The mechanisms for Pseudomonas aeruginosa colonisation in the airways of patients with bronchiectasis and cystic fibrosis are poorly understood. P. aeruginosa could evade mucociliary clearance by adhering to the basement membrane at areas denuded of intact respiratory epithelium. The authors have developed an in vitro model to study P. aeruginosa adherence to human basement membrane type-IV collagen by using scanning electron microscopy. P. aeruginosa adherence density was determined as the number of P. aeruginosa per 20 microscope fields (2,000x) to log inocular size after incubation at 37 degrees C for 45 min. The presence of phytohaemagglutinin (PHA)-E, which binds specifically to D-galactose-beta1-4-D-N-acetylglucosamine, significantly reduced P. aeruginosa adherence density compared with control. The presence of heparin and calcium also significantly reduced P. aeruginosa adherence density. P. aeruginosa adherence was not affected by the presence of proline, trans-hydroxyproline, glycine, galactose, N-acetylneuraminic acid, N-acetylglucosamine or Arachis hypogea. Pseudomonas aeruginosa adherence probably acts via recognition of the D-galactose-beta1-4-D-N-acetylglucosamine sequence on type-IV collagen and this process could be inhibited by heparin and calcium. As persistent Pseudomonas aeruginosa colonisation is detrimental to patients with cystic fibrosis and bronchiectasis and there is currently no effective treatment for its eradication, these results could lead to novel therapy for persistent Pseudomonas aeruginosa infection.

Amino Acids↗

PubMed2003

Type III secretion proteins PcrV and PcrG from Pseudomonas aeruginosa form a 1:1 complex through high affinity interactions.

BACKGROUND: Pseudomonas aeruginosa, an increasingly prevalent opportunistic pathogen, utilizes a type III secretion system for injection of toxins into host cells in order to initiate infection. A crucial component of this system is PcrV, which is essential for cytotoxicity and is found both within the bacterial cytoplasm and localized extracellularly, suggesting that it may play more than one role in Pseudomonas infectivity. LcrV, the homolog of PcrV in Yersinia, has been proposed to participate in effector secretion regulation by interacting with LcrG, which may act as a secretion blocker. Although PcrV also recognizes PcrG within the bacterial cytoplasm, the roles played by the two proteins in type III secretion in Pseudomonas may be different from the ones suggested for their Yersinia counterparts. RESULTS: In this work, we demonstrate by native mass spectrometry that PcrV and PcrG expressed and purified from E. coli form a 1:1 complex in vitro. Circular dichroism results indicate that PcrG is highly unstable in the absence of PcrV; in contrast, both PcrV alone and the PcrV:PcrG complex have high structural integrity. Surface plasmon resonance measurements show that PcrV interacts with PcrG with nanomolar affinity (15.6 nM) and rapid kinetics, an observation which is valid both for the full-length form of PcrG (residues 1-98) as well as a form which lacks the C-terminal 24 residues, which are predicted to have low secondary structure content. CONCLUSIONS: PcrV is a crucial component of the type III secretion system of Pseudomonas, but the way in which it participates in toxin secretion is not understood. Here we have characterized the interaction between PcrV and PcrG in vitro, and shown that PcrG is highly unstable. However, it associates readily with PcrV through a region located within its first 74 amino acids to form a high affinity complex. The fact that PcrV associates and dissociates quickly from an unstable molecule points to the transient nature of a PcrV:PcrG complex. These results are in agreement with analyses from pcrV deletion mutants which suggest that PcrV:PcrG may play a different role in effector secretion than the one described for the LcrV:LcrG complex in Yersinia.

Amino Acid Sequence↗

PubMed1998

Purification, characterization, and gene analysis of catechol 2,3-dioxygenase from the aniline-assimilating bacterium Pseudomonas species AW-2.

Catechol 2,3-dioxygenase (C23D; EC 1.13.1.2) was purified to homogeneity from a cell extract of Pseudomonas sp. AW-2 grown on aniline, and the purified C23D was characterized. The molecular mass estimated by gel filtration was 110 kDa. The enzyme dissociated into four identical subunits each with the molecular mass of 33 kDa. The enzyme had high activity for 3-methylcatechol as well as catechol, and differed from the enzyme from Pseudomonas putida mt-2, which carries the TOL plasmid, in optimal pH for catechol, extradiol cleavage activities for 3-methylcatechol and 4-methylcatechol, and immunochemical properties. The amino acid sequence deduced from a C23D gene, alnE, from Pseudomonas sp. AW-2 was 85.7% identical to that of 3-methylcatechol 2,3-dioxygenase from toluidine-assimilating Pseudomonas putida UCC22. AlnE was 44.1% identical to the C23D encoded by xylE in P. putida mt-2. Because XylE has low activity for 3-methylcatechol, these results suggest that the differences in substrate specificity for 3-methylcatechol among the C23Ds reflected their sequence similarity.

Amino Acid Sequence↗

PubMedDate not supplied

Siderophore production by a marine Pseudomonas aeruginosa and its antagonistic action against phytopathogenic fungi.

A marine isolate of fluorescent Pseudomonas sp. having the ability to produce the pyoverdine type of siderophores under low iron stress (up to 10 microM iron in the succinate medium) was identified as Pseudomonas aeruginosa by using BIOLOG Breathprint and siderotyping. Pyoverdine production was optimum at 0.2% (w/v) succinate, pH 6.0, in an iron-deficient medium. Studies carried out in vitro revealed that purified siderophores and Pseudomonas culture have good antifungal activity against the plant deleterious fungi, namely, Aspergillus niger, Aspergillus flavus, Aspergillus oryzae, Fusarium oxysporum, and Sclerotium rolfsii. Siderophore-based maximum inhibition was observed against A. niger. These in vitro antagonistic actions of marine Pseudomonas against phytopathogens suggest the potential of the organism to serve as a biocontrol agent.

Antifungal Agents↗

PubMed1992

Pseudomonas exit site infections in continuous ambulatory peritoneal dialysis patients.

The purpose of this study is to examine the natural history of Pseudomonas aeruginosa exit site infections in continuous ambulatory peritoneal dialysis (CAPD) patients treated with oral ciprofloxacin and local exit site care. A retrospective view was undertaken of 18 episodes of P. aeruginosa exit site infections developing in 17 patients maintained on CAPD during 1989 and 1990. Standardized therapy for the exit site infection consisted of oral ciprofloxacin (500 mg twice daily) and local exit site care with antiseptic agents. Fifteen (83%) of 18 of the pseudomonas exit site infections resolved with therapy. Three episodes (17%) required catheter removal to successfully eradicate the infection. Four of the 15 patients whose exit site infections resolved developed P. aeruginosa peritonitis 2 to 9 months after the clinical resolution of the exit site infection. The majority of pseudomonas exit site infections in CAPD patients can be successfully treated with oral ciprofloxacin and local care. Approximately 17% of the patients in this study required catheter removal to successfully eradicate the infection and an additional 22% of the patients developed pseudomonas peritonitis several months after the resolution of the exit site infection.

Administration, Oral↗

PubMed1989

The contribution of bacterial surface hydrophobicity to the process of adherence of Pseudomonas aeruginosa to hydrophilic contact lenses.

Ten isolates of Pseudomonas aeruginosa obtained from the corneas of patients with Pseudomonas keratitis adhered to soft contact lenses in significantly greater numbers than did six isolates from other body sites (P less than .05). However, there was no predominant serotype among the 10 corneal isolates tested. Isolates grown statically in broth at 37 degrees C formed a pellicle and adhered two times as much to contact lenses as did isolates grown in broth while shaking which did not form a pellicle (P less than .01). The more adherent isolates (grown at 37 degrees C) were shown to be more hydrophobic than the less adherent bacteria (grown at 26 degrees C) by their propensity to accumulate at the interface between hexadecane and saline and their movement into polyethylene glycol from dextran. These corneal isolates agglutinated erythrocytes, a process that was inhibited by dilute solutions (as low as 0.01%) of three commonly used surfactants. These same surfactants inhibited the adherence of Pseudomonas aeruginosa to soft contact lens surfaces by as much as 52%. It is concluded that hydrophobic interactions may significantly contribute to the ability of Pseudomonas aeruginosa to adhere to contact lenses.

Bacterial Adhesion↗

PubMed1979

Pseudomonas resistance to gentamicin.

66 burned patients admitted to the Burn Unit from Jan. to Sept., 1977, were studied. Topical therapy employed was mafenide or silver sulfadiazine. The most common pathogens isolated in 288 burn wound cultures were Pseudomonas aeruginosa (42%), Klebsiella-Enterobacter (16%), and Staph, aureus (13%). Pseudomonas was sensitive to gentamicin in only 36.2% of instances. In 1976, 42% of Pseudomonas isolates was sensitive. During the period 1969-1973, 85.7% of the Pseudomonas was sensitive to gentamicin.

Burns↗

PubMed2005

Effect of Pseudomonas sp. MT5 baths on Flavobacterium columnare infection of rainbow trout and on microbial diversity on fish skin and gills.

Use of Pseudomonas sp. strain MT5 to prevent and treat Flavobacterium columnare infection was studied in 2 experiments with fingerling rainbow trout Oncorhynchus mykiss. In the first experiment, length heterogeneity analysis of PCR-amplified DNA fragments (LH-PCR) was used to assess the effect of antagonistic baths on the microbial diversity of healthy and experimentally infected fish. In the 148 samples studied, no difference was found between bathed and unbathed fish, and 3 fragment lengths were detected most frequently: 500 (in 75.7% of the samples), 523 (62.2%) and 517 bp (40.5%). The species contributing to these fragment sizes were Pseudomonas sp., Rhodococcus sp. and F. columnare, respectively. A specific PCR for detection of Pseudomonas sp. MT5 was designed, but none of the tissue samples were found to be positive, most likely indicating poor adhesion of the strain during bathing. LH-PCR was found to be a more powerful tool for detecting F. columnare in fish tissue than traditional culture methods (chi2 = 3.9, df = 1, p < 0.05). Antagonistic baths had no effect on the outbreak of infection or on fish mortality. F. columnare was also detected in healthy fish prior to and after experimental infection, indicating that these fish were carriers of the disease. In the second experiment, intensive Pseudomonas sp. MT5 antagonistic baths were given daily to rainbow trout suffering from a natural columnaris infection. Again, the antagonistic bacteria had no effect on fish mortality, which reached 95 % in both control and antagonist-treated groups in 7 d.

Animals↗

PubMed2001

Combined effects of NaCl, NaOH, and biocides (monolaurin or lauric acid) on inactivation of Listeria monocytogenes and Pseudomonas spp.

This study highlighted combinations of chemical stresses that could decrease or eliminate Listeria monocytogenes and Pseudomonas spp. surviving in food processing plants. Strains of L. monocytogenes, Pseudomonas fragi, and Pseudomonas fluorescens isolated from processing environments (meat and milk) were grown at 20 degrees C up to the early stationary phase. The strains were then subjected to 30 min of physicochemical treatments. These treatments included individual or combined acid (acetic acid), alkaline (NaOH), osmotic (NaCl), and biocides (fatty acids) challenges. Survival of the strains was studied after individual or combined acid (acetic acid), alkaline (NaOH), osmotic (NaCl), and biocides (monolaurin, lauric acid) challenges. Individual pH shocks had lower efficiencies than those used in combinations with other parameters. The treatment pH 5.4 followed by pH 10.5 had a low efficiency against L. monocytogenes. The opposite combination, pH 10.5 followed by pH 5.4, led to a 3-log reduction of the L. monocytogenes population. Pseudomonas spp. strains were much more sensitive than L. monocytogenes, and population reductions of 5 and 8 log (total destruction), respectively, were observed after the same treatments. As for L. monocytogenes, the combination pH 10.5 followed by pH 5.4 is more deleterious than the opposite. Whatever the bacterial species, the most efficient treatments were combinations of alkaline, osmotic, and biocide shocks. For instance, the combination pH 10.5 and 10% NaCl plus biocides showed reductions of 5 to 8 log for both bacteria. The origins of the observed lethal effects are discussed.

Caustics↗

PubMed2006

Lethality of chlorine, chlorine dioxide, and a commercial produce sanitizer to Bacillus cereus and Pseudomonas in a liquid detergent, on stainless steel, and in biofilm.

Many factors that are not fully understood may influence the effectiveness of sanitizer treatments for eliminating pathogens and spoilage microorganisms in food or detergent residues or in biofilms on food contact surfaces. This study was done to determine the sensitivities of Pseudomonas cells and Bacillus cereus cells and spores suspended in a liquid dishwashing detergent and inoculated onto the surface of stainless steel to treatment with chlorine, chlorine dioxide, and a commercial produce sanitizer (Fit). Cells and spores were incubated in a liquid dishwashing detergent for 16 to 18 h before treatment with sanitizers. At 50 microg/ml, chlorine dioxide killed a significantly higher number of Pseudomonas cells (3.82 log CFU/ml) than did chlorine (a reduction of 1.34 log CFU/ml). Stainless steel coupons were spot inoculated with Pseudomonas cells and B. cereus cells and spores, with water and 5% horse serum as carriers. Chlorine was more effective than chlorine dioxide in killing cells and spores of B. cereus suspended in horse serum. B. cereus biofilm on stainless steel coupons that were treated with chlorine dioxide or chlorine at 200 microg/ml had total population reductions (vegetative cells plus spores) of > or = 4.42 log CFU per coupon; the number of spores was reduced by > or = 3.80 log CFU per coupon. Fit (0.5%) was ineffective for killing spot-inoculated B. cereus and B. cereus in biofilm, but treatment with mixtures of Fit and chlorine dioxide caused greater reductions than did treatment with chlorine dioxide alone. In contrast, when chlorine was combined with Fit, the lethality of chlorine was completely lost. This study provides information on the survival and sanitizer sensitivity of Pseudomonas and B. cereus in a liquid dishwashing detergent, on the surface of stainless steel, and in a biofilm. This information will be useful for developing more effective strategies for cleaning and sanitizing contact surfaces in food preparation and processing environments.

Bacillus cereus↗

PubMed1997

[Clinical values of Pseudomonas corneal ulcer treated by lamellar keratoplasty].

OBJECTIVE: The study was designed to explore the pathological mechanisms and effective methods of treatment for pseudomonas corneal ulcer. METHOD: The nearly perforating pseudomonas corneal ulcer was treated by lamellar keratoplasty and the corneal bottoms were studied histopathologically. RESULTS: 21 cases 21 eyes with pseudomonas corneal ulcers were treated by lamellar keratoplasty, the corneal contour was recovered successfully and a good optical outcome was attained. The study revealed that in the disease not only there was the corneal violent inflammatory reaction, but also there was a large amount of immune cells in the limbal bulbar conjunctiva, sclera, surroundings and base of corneal ulcer. The corneal collagen was degenerative and neovascular vessels invaded the lesion. CONCLUSIONS: Possibly, both the inflammatory and immune reactions exist in the pathological mechanisms of the pseudomonas corneal ulcer. The pathological processes can be stopped by lamellar keratoplasty and a better clinical outcome can be attained.

Adult↗

PubMed1999

[In vitro antimicrobial activity of carbapenem antibiotics against Pseudomonas aeruginosa, measured using a low-concentration Mueller-Hinton Agar culture medium].

Ohya et al. noted that the antibacterial activity of carbapenem-family antibiotics against Pseudomonas aeruginosa was significantly enhanced through lowering the basic amino acid concentration in the culture medium. They reported that there was a marked difference in antimicrobial activity of panipenem (PAPM) against Pseudomonas aeruginosa between the culture medium with Mueller-Hinton Agar (MHA) diluted with distilled water and the non-diluted culture medium. We used 2,312 strains of fresh Pseudomonas aeruginosa, isolated from clinical materials, to examine the antibacterial activity of PAPM in non-diluted and diluted culture media. For testing the susceptibility, we employed the Showa disc method and agar plate dilution method. In the Showa disc method, the inhibition diameters of the tested microbial strains showed a larger distribution for both 16-fold and 40-fold diluted MHA, compared to the non-diluted MHA. The MIC values in the agar plate dilution method were also smaller in distribution for the 16-fold as well as the 40-fold diluted MHA, compared to the non-diluted culture media. Approximately 90% of the strains showed decreased MIC values, 2-8 times in the 16-fold diluted MHA and 2-16 times in the 40-fold diluted MHA. From the above results, we confirmed that the in vitro antibacterial activity of PAPM against Pseudomonas aeruginosa was enhanced through lowering the MHA concentration.

Agar↗

PubMedDate not supplied

[Resistance of certain strains of Pseudomonas bacteria to toxic effect of heavy metal ions].

The effect of heavy metal cations (cobalt, nickel, and copper) and the anion detergent sodium dodecyl sulfate (SDS) on the barrier properties of the plasma membrane (PM) of the Co-sensitive stain Pseudomonas putida BS394 and the Co-resistant strains Pseudomonas sp. BS501 (wild-type strain) and Pseudomonas putida BS394 (pBS501) (transformed strain) was studied by high-frequency electro-orientational spectroscopy. The cations were found to rank, in order of decreasing damage inflicted on the PM, as copper > cobalt > nickel. The strains studied were found to rank, in order of increasing resistance of the PM to damage inflicted by copper and cobalt cations, as P. putida BS394 < P. putida BS394 (pBS501) < Pseudomonas sp. BS501. In order of increasing resistance to SDS, the strains ranked inversely. The strains did not differ in sensitivity to nickel cations. Investigation of the surface of intact and trypsin-treated cells by microelectrophoresis showed that the surface layers of the cell wall of wild-type and transformed cells contained increased amounts of proteins. The surface proteins of Co-resistant cells had molecular masses of 49, 40, and 32 kDa. Exposure of Co-resistant cells to trypsin considerably reduced their resistance to cobalt cations. It is assumed that the resistance of the PM of the wild-type and transformed pseudomonads to heavy metal cations is determined by plasmid pBS501 and is related to the synthesis of protective surface proteins of the cell wall.

Drug Resistance, Microbial↗

PubMedDate not supplied

[Ability of representatives of Pantoea agglomerans, as well as Bacillus subtilis and some Pseudomonas species to suppress the development of phytopathgenic bacteria and micromycetes in regulating plant growth].

The ability of representatives of Pantoea agglomerans (Erwinia herbicola (Lohnis) Dye [21]), Bacillus subtilis and some species of Pseudomonas genus to inhibit the growth of phytopathogenic bacteria and micromycetes and to regulate the growth of plants has been comparatively studied. The ability to inhibit the growth of mycellium of phytopathogenic Fusarium avenaceum, F. gibbosum, F. oxysporum was found out in all of 13 investigated strains of P. agglomerans, while the growth of F. culmorum is inhibited by 2 strains and Bipolaris sorokiniana is inhibited by 7 strains. The strains of P. agglomerans and Bacillus subtilis inhibit the growth of mycellium of these mycromycetes to the greater extent than the representatives of Pseudomonas genus. The mycellium growth of B. sorokiniana is better inhibited by B. subtilis and representatives of Pseudomonas genus. Besides the antifungal action 8 strains of P. agglomerans manifested the antagonistic activity in respect to phytopathogenic Agrobacterium tumefaciens and representatives of genera Clavibacter, Erwinia, Pseudomonas, Xanthomonas and also in respect to the microflora which is present in the cabbage and wheat seeds. The strains have been revealed which, parallel with high antagonistic activity in respect to phytopathogenic micromycetes and bacteria, stimulate the seed germination and increase the weight of the cabbage and wheat sprouts.

Bacillus subtilis↗

PubMed1975

Septic arthritis due to pseudomonas in heroin addicts.

Ten cases of septic arthritis due to Pseudomonas occurred in users of heroin. Nine cases were monarticular, two each occurring in the sternoclavicular and the sacro-iliac joints. Review of the literature suggests that the incidence of Pseudomonas septic arthritis is increasing, especially among heroin addicts. The reported cases in adults suggest a predilection for the sternoclavicular joints (eight of forty-one) which is even more pronounced among addicts (seven of twenty-four). Pseudomonas infection associated with drug abuse should be suspected in cases of isolated sternoclavicular inflammation. The drugs used for treatment of septic arthritis due to Pseudomonas should include gentamicin and carbenicillin, in conjunction with adequate drainage by aspiration or surgery.

Adult↗

PubMed1979

Tricarboxylic acid-cycle enzymes and ATP pool in facultative and obligate methylotrophs: Pseudomonas J26 and Methylomonas Pl1.

1. No essential differences were found in the activities of tricarboxylic acid-cycle enzymes in the newly isolated facultative methylotroph Pseudomonas J26 and obligate methylotroph Methylomonas Pl1. 2-Oxoglutarate dehydrogenase and succinate dehydrogenase were absent in Methylomonas Pl1; in Pseudomonas J26 the functioning of the cycle was imparied only on the methanol medium. Citrate synthase of both organisms showed low sensitivity to 2-oxoglutarate, NADH and ATP. 2. In both methylotrophs, methanol dehydrogenase was inhibited non-competitively by ATP: the activity was reduced by half by ATP at a concentration of 5 mM. 3. Concentration of ATP in the log-phase cultures of Methylomonas Pl1 was about twice as high as in Pseudomonas J26 (4.7 and 1.7 mumol/g dry wt., respectively). 4. Differences between the energy state of Methylomonas Pl1 and Pseudomonas J26 might be due to the higher ability of the former to oxidize methanol and/or lower energy requirement for C1 assimilation by the hexulose pathway in the obligate methylotroph.

Adenosine Triphosphate↗

PubMed2002

Influence of anti-alginate serum combined with gatifloxacin on mucoid pseudomonas aeruginosa biofilm morphology.

OBJECTIVE: To investigate the influence of anti-alginate serum on morphology of biofilm (BF) of mucoid Pseudomonas aeruginosa. METHODS: The modified plate culture method was used to establish a biofilm model of mucoid Pseudomonas aeruginosa in vitro. The biofilm was treated by anti-alginate serum and/or different concentrations of gatifloxacin. The samples were then detected by scanning electron microscopy (SEM) and optical microscopy after being stained with AgNO(3). A group of samples treated by none agent was used as blank control. The optical density of bacterial biofilm was determined by using computer image analysis system. RESULTS: BF was achieved on the silicon slides in all groups 7 days after the incubation of Pseudomonas aeruginosa. The silicon slides were covered by dense and black stained material in the blank group; the black stained material as mildly less in the group treated with anti-alginate serum, and much less in the group treated with gatifloxacin, and the BF was thin and only slightly stained black in the group treated with anti-alginate combined with gatifloxacin. SEM showed that the mucoid materials among bacteria was reduced and the number of bacteria was decreased and the shape of bacteria became irregular in the groups treated by anti-alginate serun and/or gatiflaxacin, especially the group treated by anti-alginate combined with gatifloxacin. Computer image analysis system showed that the mean optical density was 0.82 +/- 0.06 in the blank control group, 0.79 +/- 0.06 in anti-alginate serum group, 0.76 +/- 0.07 in of gatifloxacin group, and 0.70 +/- 0.04 in anti-alginate serum combined with gatifloxacin group. CONCLUSION: Anti-alginate serum affects the structure and morphology of the biofilm of mucoid Pseudomonas aeruginosa and destroys the biofilm structure when combined with gatifloxacin.

Alginates↗