Pseudomonas aeruginosa

Objectives: To evaluate the antibacterial activity of the total extracts, methanolic and water extract of leaves with stems and the pods of Ceratonia siliqua L. each alone and in combination with some antimicrobials on some pathogens. As the wide use of antibiotics in the treatment of bacterial infections has led to the emergence and spread of resistant strains. Many studies showed that the efficacy of antimicrobials can be improved by combining them with crude plant extracts.

Powdered grape seeds and bagasse were extracted with petroleum ether to remove fatty material and then re-extracted with different solvent mixtures to determine their total phenolics and antibacterial activities. In the grape seeds extracts the content of total phenolic compounds was found to be 627.98 mg gallic acid equivalent (GAE)/g with acetone:water:acetic acid (90:9.5:0.5) and 667.87 mg GAE/g with ethyl acetate:methanol:water (60:30:10). The bagasse extracts contained 45.44 mg GAE/g and 29.55 mg GAE/g with ethyl acetate:methanol:water (60:30:10) and ethanol:water (95:5), respectively. These extracts at 1%, 2%, 4% and 20% concentrations were tested for their antibacterial effects by using the paper disc diffusion method against some food spoilage and pathogenic bacteria including Aeromonas hydrophila ATCC 7965, Bacillus amyloliquefaciens ATCC 3842, Bacillus brevis FMC 3,

Microbially mediated oxidation of Mn(II) to Mn oxides have been demonstrated in previous studies, however, the mechanisms of bacteria how to dissolve and oxidize using a solid Mn(II) origin are poorly understood. In this study, we examined the role of extracellular polymeric substances (EPS) from P. putida strain MnB1 in enhancing dissolution of natural rhodochrosite. The results showed that P. putida strain MnB1 cell can effectively dissolve and oxidize natural rhodochrosite to generate Mn oxides, and EPS were found to play an important role in increasing dissolution of natural rhodochrosite. Compared with EPS-free treatment, dissolution rate of natural rhodochrosite in the presence of bacterial EPS was significantly increased with decreasing initial pH and increasing EPS concentration, ionic strength and rhodochrosite dosage (p < 0.05). The fourier-transform infrared spectroscopy (FTIR) analysis implies that the functional groups like N-H, C=O and C-H in EPS contributed to the dissolution of natural rhodochrosite. This study is helpful for understanding the mechanisms of the formation of biogenic Mn oxides using a solid Mn(II) origin.

To date the effect of silver-containing wound dressings on biofilms, known to be present in chronic wounds, has not been determined or documented. In this current study, we aimed to determine the antimicrobial effect of a silver-containing dressing on biofilms grown in a chambered slide model. Before the addition of a wound dressing onto a 24-hour biofilm, composed of either Pseudomonas aeruginosa, Enterobacter cloacae, Staphylococcus aureus, or a mixed bacterial community, a fluorescent dye was applied. This enabled the viability of sessile bacteria to be monitored in real-time, using a rapid form of confocal laser scanning microscopy over a contact time period of 48 hours. By analyzing all the three-dimensional data generated from the confocal time-lapse sequences, 90% of all sessile bacteria within the biofilm were observed to progressively turn red (i.e., died) within 24 hours. Total bacterial kill in the biofilm was achieved after 48 hours. This research has shown that the dressing was effective in killing the tested bacteria evident in both the tested mono and polymicrobial biofilms, which provides valuable evidence that this dressing may have an effect on biofilms found in recalcitrant chronic wounds.

Very few studies regarding production of virulence factors in different predominant serotypes of uropathogenic Pseudomonas aeruginosa are available and they have not been correlated to in vivo pathogenicity in the urinary tract. This study was carriedout with the objective to analyze the phenotypic characters of uroisolates of P. aeruginosa in vitro and to study the association of these virulence traits with their ability to cause nephropathogenicity in mouse model of ascending urinary tract infection (UTI). Protease, elastase, alginate, haemolysin, pyochelin, pyoverdin and phopholipase C were measured using standard protocols in 18 uroisolates of P. aeruginosa isolated from patients suffering from complicated UTIs. An ascending model of pyelonephritis was established in Swiss Webster (LACA) female mice with these isolates. Quantitative bacterial count and histopathological evaluation of mouse renal tissue was done which were then assessed for a possible association with elaboration...

Polyethlene terephthalate films were surface-modified with polyethylene oxide (18 500 g/mol) using a solution technique described previously. These films were investigated for their resistance to bacterial adhesion. Three bacterial strains most commonly associated with implant infections, Staphylococcus epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa, were cultured in tryptic soya broth, human plasma and human serum on the polymeric substrates. Significant reductions (between 70 and 95%) in adherent bacteria were observed on the polyethylene oxide-modified substrates compared to the untreated control polyethylene terephthalate.

Objectives: To explore contemporary antibiotic management of infections caused by carbapenemresistant Gram-negative bacteria in hospitals. Methods: Cross-sectional, internet-based questionnaire survey. We contacted representatives of all hospitals with more than 800 acute-care hospital beds in France,

Introduction: Ecthyma gangrenosum is known as a characteristic lesion of Pseudomonas aeruginosa sepsis and is usually seen in immunocompromised patients. Case presentation: A previously healthy 63-year-old man was admitted with sloughy necrotic ulcerations of the skin over his sternum. He was afebrile and in good condition. A skin biopsy revealed ecthyma gangrenosum. Blood cultures remained sterile, but a culture of biopsy material grew Pseudomonas aeruginosa. Conclusion: Ecthyma gangrenosum may develop even in the absence of bacteremia and even in immunocompetent patients. It should be considered as a possible diagnosis even when a previously healthy patient has negative blood cultures. The patient had no history of immunosuppressive disease or treatment. On admission he was afebrile (temperature of 37,2°C), and hemodynamically stable. Physical examination revealed two sloughy necrotic ulcerations of the skin over

Mutagenesis studies have been used to investigate the role of a heme ligand containing protein loop (67-79) in the activation of diheme peroxidases. Two mutant forms of the cytochrome c peroxidase of Pseudomonas aeruginosa have been produced. One mutant (loop mutant) is devoid of the protein loop and the other (H71G) contains a non-ligating Gly at the normal histidine ligand site. Spectroscopic data show that in both mutants the distal histidine ligand of the peroxidatic heme in the un-activated enzyme is lost or is exchangeable. The un-activated H71G and loop mutants show, respectively, 75% and 10% of turnover activity of the wild-type enzyme in the activated form, in the presence of hydrogen peroxide and the physiological electron donor cytochrome c 551. Both mutant proteins show the presence of constitutive reactivity with peroxide in the normally inactive, fully oxidised, form of the enzyme and produce a radical intermediate. The radical product of the constitutive peroxide reaction appears to be located at different sites in the two mutant proteins. These results show that the loss of the histidine ligand from the peroxidatic heme is, in itself, sufficient to produce peroxidatic activity by providing a peroxide binding site and that the formation of radical intermediates is very sensitive to changes in protein structure. Overall, these data are consistent with a major role for the protein loop 67-79 in the activation of di-heme peroxidases and suggest a ''charge hopping'' mechanism may be operative in the process of intra-molecular electron transfer.

We employed an in-vivo pharmacokinetic/in-vitro pharmacodynamic method to simulate bacterial killing in plasma and the interstitium of skeletal muscle tissue after intravenous administration of 2 g of cefpirome and 8 g of fosfomycin alone and in combination to patients with sepsis. Interstitial antimicrobial concentrations were determined by use of in-vivo microdialysis. CFU/ ml of Staphylococcus aureus (ATCC 29213) and Pseudomonas aeruginosa (clinical isolate) decreased by approximately 2 log 10 for plasma and muscle tissue 6 h after cefpirome and fosfomycin administration compared with the baseline, respectively. The simulation of plasma and tissue pharmacokinetics for the combined administration of these antibiotics resulted in complete eradication of S. aureus within 5 h after drug exposure. No bacterial re-growth occurred in any of the simulations within 6 h. The invitro simulation of in-vivo plasma and tissue pharmacokinetics of cefpirome and fosfomycin has shown that both antimicrobial agents kill S. aureus and P. aeruginosa strains effectively after single dose administration. This effect was most pronounced by the combined use of these antimicrobial agents. Therefore, this data corroborates antimicrobial strategies of simultaneous administration of cefpirome and fosfomycin in patients with severe soft tissue infection. #

Objectives: Time-kill studies are commonly used in investigations of new antimicrobial agents. However, they typically provide descriptive information on pharmacodynamics. We developed a mathe- matical model to capture the relationship between microbial burden and antimicrobial agent concentrations. Methods: Time-kill studies were performed with 108 cfu/mL of Pseudomonas aeruginosa at baseline. Meropenem at 0, 0.25, 1, 4, 16 and 64 3

in Pseudomonas aeruginosa ᰔ ␤-Lactamase production is the main mechanism for ␤-lactam resistance in gram-negative rods. The more threatening ␤-lactamases that have successfully emerged and are believed to spread only in Enterobacteriaceae are CTX-M-type extendedspectrum ␤-lactamases (ESBLs) (5). The acquired ␤-lactamases with wide activity spectra that are important in Pseudomonas aeruginosa include class B metallo-␤-lactamases (mostly IMP and VIM types and especially SPM-1 in Brazil) and class A ESBLs, particularly VEB-, PER-, and GES-type enzymes . However, a single CTX-M-1-producing P. aeruginosa isolate has been reported from The Netherlands (1), as well as CTX-M-2-and CTX-M-43-positive P. aeruginosa isolates in Bolivia (2). This study reports the identification of a CTX-M-2-producing P. aeruginosa strain isolated from a Brazilian teaching hospital.

The efficacy of a new rhamnolipid biosurfactants mixture to enhance the removal of pyrene from a soil artificially contaminated was investigated. The molar solubilization ratio (MSR) and the partition coefficient between the micelles and water (log K(m)) were found to be 7.5 x 10(-3) and 5.7, respectively. From soil column studies, the pyrene removal increased linearly with the concentration of the injected biosurfactants solution above the effective critical micellar concentration (0.4 g L(-1)). Flushing with a 5.0 g L(-1) biosurfactants solution increased the pyrene concentration in the effluent by 178 times. At high biosurfactants&amp;amp;amp;#39; concentrations (2.5 and 5.0 g L(-1)), the cumulative pyrene recovery reached 70%. This pyrene remobilization takes place independently of the soil organic carbon solubilization. This study provides a combination of batch and column experiments in order to find the conditions for effective soil remediation using a new rhamnolipids mixture.

Helaeomyia petrolei (oil fly) larvae inhabit the asphalt seeps of Rancho La Brea in Los Angeles, Calif. The culturable microbial gut contents of larvae collected from the viscous oil were recently examined, and the majority (9 of 14) of the strains were identified as Providencia spp. Subsequently, 12 of the bacterial strains isolated were tested for their resistance or sensitivity to 23 commonly used antibiotics. All nine strains classified as Providencia rettgeri exhibited dramatic resistance to tetracycline, vancomycin, bacitracin, erythromycin, novobiocin, polymyxin, colistin, and nitrofurantoin. Eight of nine Providencia strains showed resistance to spectinomycin, six of nine showed resistance to chloramphenicol, and five of nine showed resistance to neomycin. All 12 isolates were sensitive to nalidixic acid, streptomycin, norfloxacin, aztreonam, cipericillin, pipericillin, and cefotaxime, and all but OF008 (Morganella morganii) were sensitive to ampicillin and cefoxitin. The oil fly bacteria were not resistant to multiple antibiotics due to an elevated mutation rate. For each bacterium, the number of resistant mutants per 10 8 cells was determined separately on rifampin, nalidixic acid, and spectinomycin. In each case, the average frequencies of resistant colonies were at least 50-fold lower than those established for known mutator strain ECOR 48. In addition, the oil fly bacteria do not appear to excrete antimicrobial agents. When tested, none of the oil fly bacteria produced detectable zones of inhibition on Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, or Candida albicans cultures. Furthermore, the resistance properties of oil fly bacteria extended to organic solvents as well as antibiotics. When pre-exposed to 20 g of tetracycline per ml, seven of nine oil fly bacteria tolerated overlays of 100% cyclohexane, six of nine tolerated 10% xylene, benzene, or toluene (10:90 in cyclohexane), and three of nine (OF007, OF010, and OF011) tolerated overlays of 50% xylene-50% cyclohexane. The observed correlation between antibiotic resistance and organic solvent tolerance is likely explained by an active efflux pump that is maintained in oil fly bacteria by the constant selective pressure of La Brea's solvent-rich environment. We suggest that the oil fly bacteria and their genes for solvent tolerance may provide a microbial reservoir of antibiotic resistance genes.

The Gram-negative bacterium Pseudomonas aeruginosa is an opportunistic human pathogen which is responsible for severe nosocomial infections in immunocompromised patients and is the major pathogen in cystic fibrosis. The bacterium utilizes two interrelated quorum-sensing (QS) systems, which rely on N -acyl-homoserine lactone (AHL) signal molecules, to control the expression of virulence factors and biofilm development. In this study, we compared the protein patterns of the intracellular, extracellular and surface protein fractions of the PAO1 parent strain with those of an isogenic lasI rhlI double mutant by means of two-dimensional gel electrophoresis (2-DE). This analysis showed that the intensities of 23.7% of all detected protein spots differed more than 2.5-fold between the two strains. We only considered those protein spots truly QS regulated that were changed in the mutant in the absence of signal molecules but were rescued to the wild-type situation when the medium was supplemented with AHLs. These protein spots were characterized by MALDI-TOF peptide mapping. Twenty-seven proteins were identified that were previously reported to be AHL controlled, among them several well-characterized virulence factors. For one of the identified proteins, the serine protease PrpL, a biochemical assay was established to verify that expression of this factor is indeed QS regulated. Furthermore, it is shown that the quorum-sensing blocker C-30 specifically interferes with the expression of 67% of the AHLcontrolled protein spots of the surface fraction, confirming the high specificity of the compound. Importantly, 20 novel QS-regulated proteins were identified, many of which are involved in iron utilization, suggesting a link between quorum sensing and the iron regulatory system. Two of these proteins, PhuR and HasAp, are components of the two distinct haem-uptake systems present in P. aeruginosa . In agreement with the finding that both proteins are positively regulated by the QS cascade, we show that the lasI rhlI double mutant grows poorly with haemoglobin as the only iron source when compared with the wild type. These results add haemoglobin utilization to the list of phenotypes controlled through QS in P. aeruginosa . The surprisingly high number of AHLregulated proteins relative to the number of regulated genes suggests that quorum-sensing control also operates via post-transcriptional mechanisms. To strengthen this hypothesis we investigated the role of quorum sensing in the post-translational modification of HasAp, an extracellular protein required for the uptake of free and haemoglobin-bound haem.

Pseudomonas aeruginosa, a common agent of septicemia, enters into human endothelial cellsin vitro but the effects of bacterial infection have not been addressed properly. In this study, human umbilical vein endothelial cells (HUVEC) were infected by the noninvasive PA103 and ...

The present paper presents a hypothesis aimed at explaining why venous leg ulcers, pressure ulcers, and diabetic foot ulcers develop into a chronic state. We propose that the lack of proper wound healing is at least in part caused by inefficient eradication of infecting, opportunistic pathogens, a situation reminiscent of chronic Pseudomonas aeruginosa infections found in patients suffering from cystic fibrosis (CF). We have analyzed sections from chronic wounds by fluorescence in situ hybridization and found distinct microcolonies-the basal structures of bacterial biofilms. Several researchers have previously reported that another important hallmark of biofilm formation is development of increased tolerance to various antimicrobial measures and treatments. Furthermore, the immune response to infecting bacteria in the cystic fibrosis lung is dominated by polymorphonuclear neutrophils (PMNs), and we have recently shown that in vitro biofilms of P. aeruginosa produce a shielding mechanism that offers protection from the phagocytic activity of PMNs. 1,2 We hypothesize that the presence of P. aeruginosa in biofilms, and the lack of concomitant elimination by attended PMNs, are the main causes of inefficient eradication by antibiotic treatment and antimicrobial activity of the innate immune system, respectively. The epidemic increase in obese humans worldwide is followed by a similar increase in diabetes and cardiovascular diseases. Such patients are particularly prone to the development of chronic wounds, which become colonized by a number of bacterial species. Gjdsbl et al. 3 investigated the bacterial profile of chronic venous leg ulcers and found Staphylococcus aureus (in 93.5% of the investigated ulcers), Enterococcus faecalis (71.7%), Pseudomonas aeruginosa (52.2%), coagulase-negative staphylococci (45.7%), Proteus species (41.3%), and anaerobic bacteria (39.1%). In Denmark and in the USA, it has been estimated that 1-2% of the populations, respectively, are experiencing a nonhealing wound. 4 Consequently, this has become a burden to the health care systems and the patients experience suffering, lost employment, and reduced quality of life. Bacterial infections are generally considered to be treatable by administration of antibiotics; however, this is not always true. Contributing to the lack of successful antibiotic treatment is the ability of colonizing bacteria to establish themselves and proliferate in a biofilm. Current estimates Why chronic wounds will not heal Bjarnsholt et al.

Pyocyanin (1-hydroxy-N-methylphenazine) is a cytotoxic pigment secreted by the bacterial species Pseudomonas aeruginosa, which frequently infects the lungs of immunosuppressed patients as well as those with cystic fibrosis. Pyocyanin toxicity results presumably from the ability of the compound to undergo reduction by NAD(P)H and subsequent generation of superoxide and H 2 O 2 directly in the lungs. We report that in the presence of peroxidase mimics, microperoxidase 11, or hemin, pyocyanin undergoes oxidation by H 2 O 2 , as evidenced by loss of the pigment's characteristic absorption spectrum and by EPR detection of a free radical metabolite. The oxidation of pyocyanin is irreversible, suggesting an extensive modification of the pigment's phenazine chromophore. Oxidation of pyocyanin was observed also when exogenous H 2 O 2 was replaced by a H 2 O 2 -generating system consisting of NADH and the pigment itself. That the oxidation involves the phenolate group of pyocyanin was verified by the observation that a related pigment, phenazine methosulfate, which is devoid of this group, does not undergo oxidation by microperoxidase 11/H 2 O 2 . In contrast to intact pyocyanin, oxidized pyocyanin was less efficient in NADH oxidation and stimulation of interleukin-8 release by human alveolar epithelial A549 cells in vitro, suggesting that oxidation of pyocyanin leads to its inactivation. This study demonstrates that pyocyanin may play a dual role in biological systems, first as an oxidant and ROS generator, and second as a substrate for peroxidases, contributing to H 2 O 2 removal. This latter property may cause pyocyanin degradation and inactivation, which may be of considerable biomedical interest. D 2004 Elsevier Inc. All rights reserved.

agulase-negative staphylococci, Enterobacter spp. and Pseudomonas aeruginosa . The overall incidence of bacteremic episodes was 0.514/1,000 catheter days. Hypertension, atherosclerosis, diabetes mellitus, site of catheter implantation, duration of catheter use, Wright-Khan comorbidity index and previous history of CRB were significant risk factors associated with bacteremia in univariate analysis. Multivariate analysis revealed that a previous history of a bacteremic episode (odds ratio, OR = 2.70, 95% confidence interval, CI = 1.56-4.68), diabetes mellitus (OR = 2.37, 95% CI = 1.65-3.39), duration of catheter use 1 90 days (OR = 1.85, 95% CI = 1.35-2.55) and hypertension (OR = 1.49, 95% CI = 1.08-2.04) were still significant factors associated with bacteremia. Conclusion: Reducing CRB is still a challenge for nephrologists to reduce patient morbidity and mortality. Our study could demonstrate that diabetes, previous history of CRB, site of catheter implantation and duration of catheter use were the most important risk factors for bacteremia. Therefore, to prevent CRB, particular attention should be paid to patients with diabetes and a previous history of bacteremia following strict hygienic and aseptic rules for catheter handling associated with the regular use of antiseptic lock solutions.

Hospital-acquired urinary tract infection (UTI) is the most common infection acquired in hospitals. The aim of the study was to determine the prevalence of UTIs in Turkey. A nationwide one day pointprevalence survey was conducted. Centers for Diseases Control and Prevention (CDC) standard definitions for nosocomial UTIs were used. Data were collected by detailed uniform questionnaires for each patient with UTI. A total of 13 269 patients were investigated, the number of patients observed in each hospital varied from 21 to 1329 patients, an average of 458 patients per prevalence study per hospital. The overall prevalence of UTI was 1.7%. Fifty-eight (26.1%) of the patients had sepsis or septic shock. Twenty-five (11.3%) patients had culture-proven bloodstream infection. Over 60% (65.3%) of urinary tract infections were associated with urinary catheters. Overall, 78.4% of UTIs were culture-proven. Escherichia coli (32.4%) was the most common reported pathogen, followed by Klebsiella spp. (17.0%), Candida spp. (12.8%), Pseudomonas aeruginosa (11.7%) and enterococci 8.5%. The prevalence of ampicillin-resistant E. coli was 23.9% and accounted for 73.8% of all E. coli isolated from UTI 8.2%, and 24.6% of E. coli were resistant to quinolones and ceftriaxone, respectively. There were no resistance to carbapenems in E. coli but 6.25, 40.6, 59.4% of Klebsiella spp. were resistant to carbapenems, quinolones and ceftriaxone, respectively. The results of this first national point-prevalence study offers a reliable measure of the prevalence of nosocomial UTIs at hospitals in Turkey and provides a baseline for future studies which will enable the monitoring of trends over time.

We reviewed all episodes of peritonitis associated with exit site and/or tunnel infection (n = 87; rate, 0.1/yr; 13% of all peritonitis episodes) occurring from 1979 to 1995. The exit site or tunnel infection was diagnosed at the time or shortly after the patient presented with peritonitis in 66% of the episodes. In the other one third the exit site

Nine new metal complexes of the quinolone antibacterial agent N-propyl-norfloxacin, pr-norfloxacin, with VO 2+ , Mn 2+ , Fe 3+ , Co 2+ , Ni 2+ , Zn 2+ , MoO 2þ 2 , Cd 2+ and UO 2þ 2 have been prepared and characterized with physicochemical and spectroscopic techniques while molecular mechanics calculations for Fe 3+ , VO 2+ and MoO 2þ 2 complexes have been performed. In all complexes, pr-norfloxacin acts as a bidentate deprotonated ligand bound to the metal through the pyridone and one carboxylate oxygen atoms. All complexes are six-coordinate with slightly distorted octahedral geometry. For the complex VO(N-propyl-norfloxacinato) 2 (H 2 O) the axial position, trans to the vanadyl oxygen, is occupied by one pyridone oxygen atom. The investigation of the interaction of the complexes with calf-thymus DNA has been performed with diverse spectroscopic techniques and has shown that the complexes can be bound to calf-thymus DNA resulting to a B ! A DNA transition. The antimicrobial activity of the complexes has been tested on three different microorganisms. The complexes show equal or decreased biological activity in comparison to the free pr-norfloxacin except UO 2 (pr-norf) 2 which shows better inhibition against S. aureus.

Methods used for biosurfactant recovery include solvent extraction, precipitation, crystallization, centrifugation and foam fractionation. These methods cannot be used when distillery wastewater (DW) is used as the nutrient medium for biosurfactant production by Pseudomonas aeruginosa strain BS2, because recovery of biosurfactant by any of these methods imparts color to the biosurfactant. The biosurfactant has a nonaesthetic appearance with lowered surface active properties. These methods cannot be used for continuous recovery of biosurfactant during cultivation. Hence, a new downstream technique for biosurfactant recovery from fermented DW comprised of adsorption-desorption processes using wood-based activated carbon (WAC) was developed. This study involves batch experiments to standardize the factors affecting the rate of biosurfactant adsorption onto WAC. WAC was the most efficient adsorbent among various ones tested (i.e., silica gel, activated alumina and zeolite). The WAC (1% w v-1), equilibrium time (90 min), pH range of 5-10 and temperature of 40°C were optimum to achieve 99.5% adsorption efficiency. Adsorption kinetics and intraparticle diffusion studies revealed the involvement of both boundary layer diffusion and intraparticle diffusion. The Langmuir adsorption isotherm of WAC indicated the formation of a monolayer coverage of the biosurfactant over a homogeneous carbon surface, while the Freundlich isotherm showed high adsorption at strong solute concentrations and low adsorption at dilute solute concentrations. WAC concentration of 4% w v-1 facilitated complete removal of the biosurfactant from collapsed foam (contained 5-fold higher concentration of biosurfactant than was present in fermented DW). Biosurfactant adsorption was of chemisorption type. Acetone (polar solvent) was a specific viable eluant screened among various ones tested because it selectively facilitated maximum recovery, i.e., 89% biosurfactant from WAC. By acetone treatment, complete regeneration of WAC was feasible and WAC can be reused for biosurfactant recovery up to 3 cycles. The recovered biosurfactant showed improved surface-active property (i.e., much lower critical micelle concentration value of 0.013 verses 0.028 mg mL-1 for biosurfactant recovered by classical methods). The reuse potential of WAC was assessed and results suggest that the carbon can be reused for three consecutive cycles for biosurfactant adsorption from fermented wastewater without any decrease in adsorption efficiency. Thus, this process forms a basis for continuous recovery of biosurfactant from fermented DW and concentrated foam. This process reduces the use of high cost solvent, avoids end product inhibition and minimizes product degradation.

Bacterial, viral and protozoal infections may cause severe reproductive losses. The present paper reviews the risk factors, clinical signs and preventive measures for the most important venereal or potential sexually transmitted diseases in horses. The stallion and use of semen for artificial insemination represent major risk factors for the transmission of bacterial contaminants of the penis, including Streptococcus equi subspecies zooepidemicus, Pseudomonas aeruginosa and Klebsiella pneumoniae, known to cause endometritis and infertility in the mare. The role of the stallion in disease transmission is also due to the non-clinical manifestation of diseases such as contagious equine metritis and equine viral arteritis. Dourine has been eradicated from many countries, but continues to be a problem in other areas of the globe. Strategies for the prevention of introduction and transmission of diseases in breeding operation are discussed.

The postantibiotic effects (PAEs) of imipenem and norfloxacin were tested against Staphylococcus aureus, Streptococcus (Enterococcus) faecalis, Escherichia coli, and Pseudomonas aeruginosa. Amikacin was tested against the same bacteria except Streptococcus faecalis. For in vitro tests, a viable count-washing method was used, and for in vivo tests, the thread technique in normal mice was used. All three drugs produced PAEs of 1.1 to 3.8 h in vitro and 1.4 to 4.3 h in vivo against the pathogens tested. In vitro and in vivo results correlated well. The PAE had a significantly (P < 0.01 to 0.001) longer duration in vivo than in vitro, but the PAE of imipenem on Staphylococcus aureus was longer in vitro. The PAE was not due to residual antibiotics at the site of infection, and no PAE was obtained if at any time the antibiotic concentration at the infection site reached the MIC for the pathogen tested. The results indicate that the presence of a PAE may enable antibiotics to be given more intermittently without a loss of efficacy and that the PAE can only be induced if the level of the antibiotic exceeds the MIC for the pathogen in question for at least several minutes. * Corresponding author. ATCC 29272, E. coli ATCC 25922, and P. aeruginosa ATCC 27853. The two gram-negative bacteria were found to be resistant to serum by the test described by Olling et al. (26). Mice. Female BALB/c mice (weight, 20 to 25 g) were used. Threads. Pure cotton thread (Falk, Malmb, Sweden) was

Background: We studied whether the sinuses might be foci for Pseudomonas aeruginosa lung infection. Methods: Endoscopic Sinus Surgery was performed in 78 CF patients; PFGE was used for bacterial genotyping. Material from sinuses and lungs were Gram-stained to detect biofilms. Immunoglobulins were measured in serum and saliva. Results: When P. aeruginosa was cultured simultaneously from the sinuses and the lungs they were genetically identical in 38 of the 40 patients (95%). In the sinuses, P. aeruginosa formed biofilms with minimal cellular inflammation, probably because of a significantly higher local production of secretory IgA compared with IgG (p b 0.001). Conclusions: We have shown that P. aeruginosa form biofilm in the sinuses, which constitute an important bacterial reservoir for subsequent lung infection. The high amount of IgA in the upper airways probably protects P. aeruginosa from the inflammatory immune system, and they can proceed unnoticed into a permanent infectious focus that cannot be eradicated with antibiotics.

Polymerase chain reaction-amplification and subsequent sequencing of the variable region of a novel integron, In51, from Pseudomonas aeruginosa revealed the presence of a novel aminoglycoside adenylyltransferase gene, aadA6, together with an open reading frame of unknown function, orfD. AADA6 enzyme has only 75% amino acid identity with AADA1 and is able to confer high level resistance to streptomycin and spectinomycin in Escherichia coli. ß 0167-4781 / 99 / $^see front matter ß 1999 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 7 -4 7 8 1 ( 9 9 ) 0 0 2 0 2 -X

Chronic otitis externa in dogs is often associated with Pseudomonas aeruginosa infection. Fluoroquinolones are often used for treating such infections. Fluoroquinolone resistance mechanisms were characterized in 10 strains of P. aeruginosa isolated from chronic canine otitis externa. Nine out of ten strains harbored a mutation in the gyrA gene and presented an overexpression of efflux pump(s). There was a good correlation between the lipophilicity of the fluoroquinolone being tested and the effect of the efflux pump inhibitor in the final MIC. Therefore, both mechanisms, mutation in the gyrA gene and increased efflux pump(s), seem to play an important role in the acquisition of fluoroquinolone resistance in veterinary clinical isolates of P. aeruginosa. Levels of resistance to fluoroquinolones suggest that they could not be a good choice for systemic therapy of Pseudomonas otitis.

Pharmaceutically important c-linolenic acid (GLA) was produced (4.1 mg g)1 dry wt) by laboratory grown cyanobacterium Fischerella sp. colonizing Neem (Azadirachta indica) tree bark. GLA isolated from the test cyanobacterium was active against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25992, Salmonella typhi (local strain), Pseudomonas aeruginosa ATCC 27853 and Enterobacter aerogenes MTCC 2822. The overproduction of GLA was also monitored by altering phosphate and nitrate levels in the nutrient medium. A doubling in phosphate concentration (58 lM) increased GLA level up to 12% over that of control cells while half of this phosphate level reduced GLA synthesis by 8%. In contrast, elevated nitrate concentrations (5 and 10 mM) stimulated biomass yield but not GLA, as the levels approximated to the nitrate-lacking control. The antibacterial potential of GLA from Fischerella sp. grown at varying P or N levels was at variance as evidenced by the diameter of inhibition zones against S. aureus. This variation in inhibition zones reflected differing levels of GLA as ascertained quantitatively by HPLC.

An innovative bioprocess method, Systematic Environmental Molecular Bioremediation Technology (SEMBT) that combines bioaugmentation and biostimulation with a molecular monitoring microarray biochip, was developed as an integrated bioremediation technology to treat S-and ...

An eco-friendly microbial method for synthesis of silver colloid solution with antimicrobial activity is developed using a fungal strain of Peni-cillium purpurogenum NPMF. It is observed that increase in concentration of AgNO3 increases the formation of silver nanoparticle. At ...

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Objective: To evaluate the safety of a new ultravitrification closed device. Design: Ultravitrification research. Setting: Private assisted reproduction center. Animal(s): Microorganisms (bacteria). Intervention(s): A styrofoam container holding 1,000 mL of liquid nitrogen (LN2) was contaminated with Pseudomonas aeruginosa and Escherichia coli. Forty closed devices (Ultravit) and 20 open devices (Cryotop) loading approximately 0.5 mL of antibiotic-free medium were plunged into this contaminated LN2 for 5-10 seconds and then inoculated into selective culture dishes. Colony-forming units were analyzed and counted after an overnight incubation at 37 C. Main Outcome Measure(s): Detection of micro-organisms in different devices after incubation. Result(s): There was no contamination in any of the closed devices, whereas in 45% of open devices these bacteria were present. Conclusion(s): With this study we demonstrated, in an experimental model using contaminated LN2, that this new closed device is a safe system that does not allow cell contact with LN2, avoiding cell contamination. (Fertil Steril Ò 2011;95:1777-9.

1 920 patients hospitalized in ICUs for an aggregate of 9 997 days acquired 249 DAIs, accounting for a rate of 13.0% and 24.9 DAIs per 1 000 ICU-days. The ventilator-associated pneumonia (VAP) rate was 31.3 per 1 000 ventilator-days; the central venous catheter-associated bloodstream infections (CVC-BSI) rate was 7.7 cases per 1 000 catheter-days; and the rate for catheter-associated urinary tract infections (CAUTI) was 5.1 cases per 1 000 catheter-days. Extra mortality for VAP was 24.5% (RR 2.07, P < 0.001); for CVC-BSI the rate was 15.0% (RR 2.75, P = 0.028). Methicillinresistant strains accounted for 73.5% of all Staphylococcus aureus DAIs; 40.5% of the Enterobacteriaceae were resistant to ceftriaxone, 40.8% were resistant to ceftazidime, and 32.0% were resistant to piperacillin-tazobactam. Sixty-five percent of Pseudomonas aeruginosa isolates were resistant to ciprofloxacin, 62.0% were resistant to ceftazidime, 29.4% were resistant to piperacillin-tazobactam, and 36.1% were resistant to imipenem. Conclusions. The high rates of DAIs in the Peruvian hospitals in this study indicate the need for active infection control. Programs consisting of surveillance of DAIs and implementation of guidelines for infection prevention can ensure improved patient safety in the ICUs and throughout hospitals. ABSTRACT Key words Espichan MJ, et al. Device-associated infection rates and mortality in intensive care units of Peruvian hospitals: findings of the International Nosocomial Infection Control Consortium. Rev Panam Salud Publica. 2008;24(1):16-24.

Medical-grade poly(vinyl chloride) (PVC) was chemically modified to study how the incorporation of monovalent silver influences Pseudomonas aeruginosa adhesion and colonization. The modification investigated consisted of a radio frequency-oxygen (RF-O 2 ) glow discharge pre-functionalization, followed by a two-step wet-treatment in sodium hydroxide and silver nitrate solutions. X-ray photoelectron spectroscopy (XPS) analysis and contact angle measurements were used to investigate the chemical nature and surface wettability of the films following each step of the modification. XPS analysis proved that the RF-O 2 plasma pre-functionalization of native PVC reproducibly increased the amount of functional groups representative of PVC additives, including ether/alcohol, esters and carboxyl groups. More specifically, we demonstrated that the O2 % CQO groups representative of the phthalic ester and zinc carboxylate additives identified for native PVC increased by two-fold following the RF-O 2 plasma pre-functionalization step. Although RF-O 2 pre-functionalization did not have an effect on the silver content of the NaOH/AgNO 3 treated substrates, such a modification was necessary for biomaterial products that did not have reproducible surfaces amongst production lots. XPS analysis also demonstrated that saponification with sodium hydroxide (NaOH) of esters, like those of the phthalic ester additives of PVC is a simple, irreversible method of hydrolysis, which produced sodium carboxylate and sodium phthalate salts. Exposure of native PVC to NaOH resulted in an increased surface hydrophilicity (from ca 90 to ca 60 ) due to dechlorination. XPS analysis following further incubation in silver nitrate demonstrated that silver ions can be trapped when the sodium of sodium carboxylate is replaced by silver after performing a second treatment with a monovalent silver-containing solution. The creation of silver salt on native PVC resulted in an ultra-hydrophobic (>120 ) surface. The chemical modifications using NaOH and AgNO 3 wet treatments completely inhibited bacterial adhesion of four strains of P. aeruginosa to both native and oxygen-pre-functionalized PVC, and efficiently prevented colonization over longer periods (72 h). Our results suggest that surface modifications that incorporate silver ions would be extremely effective at reducing bacterial colonization to medical devices. r

Aims: The effect of thermal stresses on survival, injury and nisin sensitivity was investigated in Salmonella Enteritidis PT4, PT7 and Pseudomonas aeruginosa. Methods and Results: Heating at 55°C, rapid chilling to 0á5°C or freezing at ±20°C produced transient sensitivity to nisin. Cells were only sensitive if nisin was present during stress. Resistance recovered rapidly afterwards, though some cells displayed residual injury. Injury was assessed by SDS sensitivity, hydrophobicity changes, lipopolysaccharide release and NPN uptake. LPS release and hydrophobicity were not always associated with transient nisin sensitivity. Uptake of NPN correlated better but persisted longer after treatment. Conclusions: Thermal shocks produce transient injury to the outer membrane, allowing nisin access. After treatment, the permeability barrier is rapidly restored by a process apparently involving reorganization rather than biosynthetic repair. Signi®cance and Impact of the Study: Inclusion of nisin during food treatments that impose sub-lethal stress on Gram negatives could increase process lethality, enhancing microbiological safety and stability.

Patogeensed gramnegatiivsed pulkbakterid on kogu maailmas olulised hospitaalinfektsioonide tekitajad (1), mille levik intensiivravi osakondades ja antibiootikumiresistentsus (2, 3) põhjustab ravi ebaõnnestumist, suurt suremust ja ravikulude kasvu (4). Olulisemad multiresistentsed patogeenid on Acinetobacter baumannii, Pseudomonas aeruginosa ja Klebsiella pneumoniae, millest kaks esimest on mittefermentatiivsed keskkonnast pärinevad bakterid, viimane aga ka tervete inimeste seedekulglas esinev enterobakter (5-7). Eesti haiglate IR-osakondades levinud A. baumannii, P. aeruginosa ja K. pneumoniae tüvede osakaal teiste patogeenide seas ning antibiootikumitundlikkus ei ole teada. Samas on lokaalne mikroobide liigiline jaotus ja antibiootikumitundlikkus abiks empiirilise ravi valikul. Eesti mikrobioloogialaborites on kasutusel peamiselt patogeenide kvalitatiivne (tundlik/mõõ

The aim of the present study was to assess the efficacy and safety of colistimethate sodium therapy in multidrugresistant nosocomial infections caused by Pseudomonas aeruginosa or Acinetobacter baumannii in neonates and children. Methods: Pediatric patients hospitalized at the Uludag University Hospital who had nosocomial infections caused by multidrug-resistant P. aeruginosa or A. baumannii, were enrolled in the study. Colistimethate sodium at a dosage of 50-75 ¥ 10 3 U/kg per day was given i.v. divided into three doses. Results: Fifteen patients received 17 courses of colistimethate sodium for the following infections: ventilator-associated pneumonia (n = 14), catheter-related sepsis (n = 1) and skin and soft-tissue infection (n = 2). The mean age of patients was 53.2 + 74.7 months (range, 8 days-15 years) and 60% were male. Mortality was 26.6%. Conclusion: Colistimethate sodium appears to be safe and effective for the treatment of severe infections caused by multidrug-resistant P. aeruginosa or A. baumannii in pediatric patients.

Hosing with water is the most common approach to cleaning in the food industry. Measurements of the removal of Pseudomonas aeruginosa biofilm from stainless steel using a high pressure hose showed that, over the range of pressures tested, impact pressure does not significantly affect microbial removal. Nozzle pressures of 2.5 Â 10 6 and 9.5 Â 10 6 Pa were used, and the distance between the nozzle and target surface was between 20 and 120 cm. When using cold water, microbial removal increased (p < 0.001) from 2.9-to 4.1-to 4.9-log 10 as the time exposed to the water spray increased from 5 to 30 to 60 s. With hot water, microbial removal was 4.9-, 5.1-, and 5.2-log 10 when using the same exposure times. The use of detergent followed by spraying with water increased (p < 0.001) the removal of organisms to 5.6-log 10 .

Outer membrane proteins (OMPs) of Gram-negative bacteria are key molecules that interface the cell with the environment. Traditional biochemical and genetic approaches have yielded a wealth of knowledge relating to the function of OMPs. Nonetheless, with the completion of the Escherichia coli genome sequencing project there is the opportunity to further expand our understanding of the organization, expression and function of the OMPs in this Gram-negative bacterium. In this report we describe a proteomic approach which provides a platform for parallel analysis of OMPs. We propose a rapid method for isolation of bacterial OMPs using carbonate incubation, purification and protein array by two-dimensional electrophoresis, followed by protein identification using mass spectrometry. Applying this method to examine E. coli K-12 cells grown in minimal media we identified 21 out of 26 (80%) of the predicted integral OMPs that are annotated in SWISS-PROT release 37 and predicted to separate within the range of pH 4–7 and molecular mass 10–80 kDa. Five outer membrane lipoproteins were also identified and only minor contamination by nonmembrane proteins was observed. Importantly, this research readily demonstrates that integral OMPs, commonly missing from 2D gel maps, are amenable to separation by two-dimensional electrophoresis. Two of the identified OMPs (YbiL, YeaF) were previously known only from their ORFs, and their identification confirms the cognate genes are transcribed and translated. Furthermore, we show that like the E. coli iron receptors FhuE and FhuA, the expression of YbiL is markedly increased by iron limitation, suggesting a putative role for this protein in iron transport. In an additional demonstration we show the value of parallel protein analysis to document changes in E. coli OMP expression as influenced by culture temperature.

Objectives: Bacteria play a leading role in acute exacerbations of chronic obstructive pulmonary disease (COPD), but we lack predictors of bacterial etiology. We developed a prediction model for infection with gram-negative enteric bacteria (GNEB) and Pseudomonas aeruginosa. Methods: Clinical presentation, sputum characteristics, microbial sputum patterns, lung function and previous and concomitant medication were prospectively recorded in patients with moderate to severe exacerbation of COPD. Risk factors for a specific bacterial etiology were c alculated and a prediction model developed. Results: A total of 193 patients with acute exacerbation were included. In 121 (62.6%) of them a microbial etiology could be identified, most frequently Haemophilus influenzae (32 strains), Streptococcus pneumoniae (22 strains) and P. aeruginosa (12 strains). Multivariate analysis identified severe airflow obstruction and use of systemic steroids as predictors for exacerbation due to gram-negative enteric bacilli and P. aeruginosa. A prediction model including FEV1 < 35% of predicted value, systemic steroid use and prior antibiotic therapy within preceeding 3 months had a negative predictive of 89%, being a helpful tool in excluding patients at risk of exacerbation due to gram-negative enteric bacilli and P. aeruginosa when all criteria are absent. Conclusion: A simple prediction model based on three factors may identify COPD patients at low risk for exacerbations with gram-negative enteric bacilli and P. aeruginosa.

Intraclonal genome diversity of Pseudomonas aeruginosa was studied in one of the most diverse mosaic regions of the P. aeruginosa chromosome. The ca. 110-kb large hypervariable region located near the lipH gene in two members of the predominant P. aeruginosa clone C, strain C and strain SG17M, was sequenced. In both strains the region consists of an individual strain-specific gene island of 111 (strain C) or 106 (SG17M) open reading frames (ORFs) and of a 7-kb stretch of clone C-specific sequence of 9 ORFs. The gene islands are integrated into conserved tRNA Gly genes and have a bipartite structure. The first part adjacent to the tRNA gene consists of strain-specific ORFs encoding metabolic functions and transporters, the majority of which have homologs of known function in other eubacteria, such as hemophores, cytochrome c biosynthesis, or mercury resistance. The second part is made up mostly of ORFs of yet-unknown function. Forty-seven of these ORFs are mutual homologs with a pairwise amino acid sequence identity of 35 to 88% and are arranged in the same order in the two gene islands. We hypothesize that this novel type of gene island derives from mobile elements which, upon integration, endow the recipient with strain-specific metabolic properties, thus possibly conferring on it a selective advantage in its specific habitat.