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Pseudomonas Aeruginosa Strains (Pseudomona aeruginosa + strain)
Selected AbstractsElution kinetics, antimicrobial efficacy, and degradation and microvasculature of a new gentamicin-loaded collagen fleeceJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2009Olaf Kilian Abstract Management of bone and soft tissue infections generally includes surgical procedures as well as attendant treatment and prevention with gentamicin-loaded fleeces. Conventional gentamicin-containing collagen fleeces currently in use are strongly acidic and exhibit limited biocompatibility thereby adversely affecting wound healing. To improve the antibiotic delivery system, a new phosphate-buffered, gentamicin-loaded fleece with pH,neutral properties has been developed (Jason G®). This study aimed at comparing the elution kinetics of gentamicin release and the antimicrobial efficacy of conventional fleeces with the newly developed fleece in vitro. In addition, degradation and microvasculature of implanted fleeces were examined in a rat model and assessed using histology, as well as detection of ED-1 and PECAM-expression using immunohistochemistry. We show that the phosphate-buffered fleeces have reduced release (p < 0.05) of the integrated gentamicin. However, all of the fleeces tested had a significant antimicrobial effect on the growth of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa strains (p < 0.01). Among the fleeces tested, the new Jason G® fleece had the weakest but nevertheless sufficient antimicrobial effectiveness. Evaluation of the antibiotic effect in the prevention of an infection showed no differences between the applied fleeces. Following surgical implantation of fleece in the backs of Wistar rats we observed, on day 5 after implantation, an increase in cell infiltration and microvascularization with the phosphate-buffered fleece as compared with conventional fleeces, which show necrotic cells on their surface. Unlike the acidic fleeces, on day 15 after implantation the pH,neutral fleece was resorbed widely. Here, we show that the new, pH,neutral, gentamicin-containing fleece Jason G® exhibits good overall antimicrobial effectiveness against both gram-positive and gram-negative bacteria in vitro with improved degradation properties and microvasculature formation in vivo. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] The dual roles of AlgG in C-5-epimerization and secretion of alginate polymers in Pseudomonas aeruginosaMOLECULAR MICROBIOLOGY, Issue 4 2003Sumita Jain Summary Pseudomonas aeruginosa strains causing chronic pulmonary infections in cystic fibrosis patients produce high levels of alginate, an exopolysaccharide that confers a mucoid phenotype. Alginate is a linear polymer of d -mannuronate (M) and variable amounts of its C-5-epimer, l -guluronate (G). AlgG is a periplasmic C-5-epimerase that converts poly d -mannuronate to the mixed M+G sequence of alginate. To understand better the role and mechanism of AlgG activity, a mutant was constructed in the mucoid strain FRD1 with a defined non-polar deletion of algG . Instead of producing poly mannuronate, the algG deletion mutant secreted dialysable uronic acids, as does a mutant lacking the periplasmic protein AlgK. High levels of unsaturated ends and the nuclear magnetic resonance spectroscopy pattern revealed that the small, secreted uronic acids were the products of extensive polymer digestion by AlgL, a periplasmic alginate lyase co-expressed with AlgG and AlgK. Thus, AlgG is bifunctional with (i) epimerase activity and (ii) a role in protecting alginate from degradation by AlgL during transport through the periplasm. AlgK appears to share the second role. AlgG and AlgK may be part of a periplasmic protein complex, or scaffold, that guides alginate polymers to the outer membrane secretin (AlgE). To characterize the epimerase activity of AlgG further, the algG4 allele of poly mannuronate-producing FRD462 was shown to encode a protein lacking only the epimerase function. The sequence of algG4 has a Ser-272 to Asn substitution in a serine,threonine-rich and conserved region of AlgG, which revealed a critical residue for C-5-epimerase activity. [source] Genotypic characterization of Pseudomonas aeruginosa strains recovered from patients with cystic fibrosis after initial and subsequent colonizationPEDIATRIC PULMONOLOGY, Issue 4 2001Anne Munck MD Abstract Chronic infection by Pseudomonas aeruginosa (PA) in patients with cystic fibrosis (CF) is preceded by a period of colonization and acute infection. Early aggressive antibiotic treatment of initial colonisation may prevent or at least delay chronic pulmonary infection. We initiated treatment with a combination of IV ,-lactam tobramycin, followed by nebulized colistin when PA was first isolated from patients with CF. Subsequent serial PA isolates obtained from these colonized CF patients were characterized by means of molecular methods to determine whether they were genetically related to the initial strain. Initial colonization was eradicated in all 19 patients. All patients reacquired PA within 3,25 months during the 3 years of follow-up. Fourteen patients acquired a new PA strain with a distinct genotypic profile, suggesting a new source of contamination. Five patients had two PA isolates with identical genotypes, suggesting either previous undetected respiratory tract colonization or a persistent environmental source of contamination. Pediatr Pulmonol. 2001; 32:288,292. © 2001 Wiley-Liss, Inc. [source] Microbiology of Normal External Auditory Canal,THE LARYNGOSCOPE, Issue 11 2001David W. Stroman PhD Abstract Objectives To isolate and characterize bacteria and fungi from the healthy ear and to obtain susceptibility profiles on each bacterial isolate. Study Design Prospective. Methods Specimens were collected from the external canals and cerumen of healthy subjects. Species-level identification was obtained by combining phenotypic and genotypic data. End-point minimal inhibitory concentration testing was performed using National Committee for Clinical Laboratory Standards recommended methods. Results One hundred sixty-four subjects were cultured. Seventeen canal and 16 cerumen specimens showed no growth. One hundred forty-eight cerumen specimens yielded 314 organisms, including 23 fungi. One hundred forty-seven canal specimens yielded 310 organisms, including 7 fungi. Of 291 bacteria isolated from cerumen, 99% were Gram-positive. Of 302 bacteria isolated from the canal, 96% were Gram-positive. Staphylococci were 63% of both the cerumen bacteria and the canal bacteria. Coryneforms represented 22% of the bacteria in cerumen and 19% in the canal. Turicellaotitidis was the primary coryneform isolated from both the canal and the cerumen. Streptococci-like bacteria were 10% from the cerumen, 7% from the canal. In both cerumen and canal, Alloiococcusotitis was more than 95% of the streptococci-like bacteria. Fifteen gram-negative organisms were isolated from the canal and cerumen, including four Pseudomonas aeruginosa strains. The percentages of Staphylococcus epidermidis isolates that had high-level resistance (,8 ,g/mL) were as follows: to neomycin, 28% from cerumen and 11% from the canal; to oxacillin, 28% from cerumen and 25% from the canal; and to ofloxacin, 15% from cerumen and 19% from the canal. ConclusionsTurcella otitidis and A. otitidis were present with a much higher frequency than previously described, lending evidence that they be considered normal otic flora. Corynebacterium auris, previously reported only in children, was isolated from normal adults. [source] Antibacterial Nitric Oxide-Releasing Polyester for the Coating of Blood-Contacting Artificial MaterialsARTIFICIAL ORGANS, Issue 7 2010Amedea B. Seabra Abstract The emergence of multidrug-resistant bacteria associated with blood-contacting artificial materials is a growing health problem, which demands new approaches in the field of biomaterials research. In this study, a poly(sulfhydrylated polyester) (PSPE) was synthesized by the polyesterification reaction of mercaptosuccinic acid with 3-mercapto-1,2-propanediol and blended with poly(methyl methacrylate) (PMMA) from solution, leading to solid PSPE/PMMA films, with three different PSPE : PMMMA mass ratios. These films were subsequently S-nitrosated through the immersion in acidified nitrite solution, yielding poly(nitrosated)polyester/PMMA (PNPE/PMMA) films. A polyurethane intravascular catheter coated with PNPE/PMMA was shown to release nitric oxide (NO) in phosphate buffered saline solution (pH 7.4) at 37°C at rates of 4.6 nmol/cm2/h in the first 6 h and 0.8 nmol/cm2/h in the next 12 h. When used to coat the bottom of culture plates, NO released from these films exerted a potent dose- and time-dependent antimicrobial activity against Staphylococcus aureus and a multidrug-resistant Pseudomonas aeruginosa strains. This antibacterial effect of PSPE/PMMA films opens a new perspective for the coating of blood-contacting artificial materials, for avoiding their colonization with highly resistant bacteria. [source] | ||||||||||