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Gram-negative Infections (gram-negative + infections)
Selected AbstractsGram-negative meningitis and infections in individuals treated with intrathecal baclofen for spasticity: a retrospective studyDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 6 2006Colleen A Wunderlich MD MSc The aim of this retrospective study was to describe signs, symptoms, and clinical outcomes of individuals undergoing intrathecal baclofen (ITB) therapy who experienced pumprelated Gram-negative infections including meningitis. Participants included 12 individuals (nine males, three females) aged 10 to 32 years (mean 17y 9mo), nine of whom had quadriplegic CP. A total of 571 baclofen pump surgeries were performed with 45 total infections. Of the 45 infections, 12 were by Gram-negative organisms, two resulting in meningitis. Ten of 12 Gram-negative infections (21 site encounters) occurred within 60 days of surgery. Eleven of 12 pumps were explanted. By site encounters, Pseudomonas aeruginosa accounted for eight Gram-negative infections, Escherichia coli for five, Proteus for three, Enterobacter cloacae for two, and Klebsiella, Enterobacter aerogenes, and Enterobacter vulnaris for one each. Two individuals with Gram-negative meningitis were admitted 72 to 96 hours after hospital discharge following pump replacement. Both patients had rapid deterioration requiring transfer to the pediatric intensive care unit, and developed coagulopathy and decrease in responsiveness. Both have improved and have elected not to replace the ITB pump. In Gram-negative infections in ITB therapy, the progression of signs and symptoms can be swift and devastating. Identification of the infectious agent in such cases is imperative; these infections can quickly become life threatening. [source] Effect of long-term nebulized colistin on lung function and quality of life in patients with chronic bronchial sepsisINTERNAL MEDICINE JOURNAL, Issue 7 2007D. P. Steinfort Abstract Recurrent Gram-negative bacterial infection is a significant cause of death in patients with bronchiectasis and severe chronic obstructive pulmonary disease (COPD). Nebulized colistin in cystic fibrosis has shown maintenance of pulmonary function and improved symptom scores. We prospectively followed 18 patients with chronic bronchial sepsis treated with nebulized colistin 30 mg daily. Mean decline in forced expiratory volume in 1 s was significantly slower following commencement of inhaled colistin (44 mL/year vs 104 mL/year, P = 0.035). Mean decline in forced vital capacity was also significantly slower following commencement of colistin (48 mL/year vs 110 mL/year, P = 0.033). Patient-reported quality of life improved following commencement of colistin (3.6 vs 6.2, P = 0.001). No patient had isolates resistant to colistin. No side-effects were reported by patients in the cohort. Use of inhaled colistin in the treatment of bronchiectasis and severe (COPD) in patients with recurrent Gram-negative infections is safe. Inhaled colistin may improve quality of life and slow decline in forced expiratory volume in 1 s and forced vital capacity. [source] Induction of complement sensitivity in Escherichia coli by citric acid and low pHJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2001C. Ocaņa-Morgner Aims:,The lytic functions of the complement system play an important role in the control of Gram-negative infections. Complement-resistant Escherichia coli LP1395 (O18) grown under normal conditions can survive the bactericidal action of complement present in human serum. Towards elucidating the mechanisms of complement resistance, the resistance of E. coli LP1395 grown under conditions of low pH and in the presence of citric acid was tested. Methods and Results:,E. coli LP1395 becomes sensitive to complement after growth in the presence of citric acid at pH 5. Complement resistance could be restored when the cells were transferred to pH 7 media. However, this recovery was greatly impaired when the cells were transferred to pH 7 media with chloramphenicol. This implies that protein synthesis may be involved in complement resistance. The cells exposed to citric acid at pH 5 showed no indication of a generalized outer membrane (OM) permeability when compared with those grown under normal conditions in terms of sensitivity to lysozyme, uptake of lipophilic dye, or sensitivity to a number of antibiotics. Conclusions:,Complement-resistant LP1395 may acquire a sensitivity to complement due not to a generalized disruption of the OM barrier, but possibly to the alteration of the activity of one or more normal complement resistance factors. Significance and Impact of the Study:,The elucidation of the echanisms of complement resistance of Gram-negative pathogens would bring important information about bacterial infections. Complement resistance factors could also be potential targets in antimicrobial therapies. [source] Molecular epidemiology of clinically significant antibiotic resistance genesBRITISH JOURNAL OF PHARMACOLOGY, Issue S1 2008P M Hawkey Antimicrobials were first introduced into medical practice a little over 60 years ago and since that time resistant strains of bacteria have arisen in response to the selective pressure of their use. This review uses the paradigm of the evolution and spread of beta-lactamases and in particular beta-lactamases active against antimicrobials used to treat Gram-negative infections. The emergence and evolution particularly of CTX-M extended-spectrum beta-lactamases (ESBLs) is described together with the molecular mechanisms responsible for both primary mutation and horizontal gene transfer. Reference is also made to other significant antibiotic resistance genes, resistance mechanisms in Gram-negative bacteria, such as carbepenamases, and plasmid-mediated fluoroquinolone resistance. The pathogen Staphylococcus aureus is reviewed in detail as an example of a highly successful Gram-positive bacterial pathogen that has acquired and developed resistance to a wide range of antimicrobials. The role of selective pressures in the environment as well as the medical use of antimicrobials together with the interplay of various genetic mechanisms for horizontal gene transfer are considered in the concluding part of this review. British Journal of Pharmacology (2008) 153, S406,S413; doi:10.1038/sj.bjp.0707632 [source] Tigecycline: in-vitro performance as a predictor of clinical efficacyCLINICAL MICROBIOLOGY AND INFECTION, Issue 4 2007P. Hawkey Abstract The incidence of nosocomial disease caused by Gram-negative pathogens is increasing, and infections caused by Enterobacter, Klebsiella, Acinetobacter, Escherichia coli and Pseudomonas aeruginosa are more commonly refractive to traditional antimicrobial agents, including aminoglycosides, fluoroquinolones and broad-spectrum cephalosporins. The most important mechanism of resistance to ,-lactam antibiotics among Gram-negative bacilli involves the production of ,-lactamases. Extended-spectrum ,-lactamases are particularly worrisome, since they are often associated with multidrug resistance phenotypes, which can pose a significant therapeutic challenge. Novel agents for the treatment of Gram-negative infections are uncommon, as recent emphasis has been placed on the development of agents targeting drug-resistant strains of Gram-positive bacteria, e.g., streptococci, enterococci and staphylococci. Tigecycline, a semi-synthetic derivative of minocycline, has a unique and novel mechanism of action, which not only allows this agent to overcome the well-known tet gene-encoded resistance mechanisms, but also maintains its activity against Gram-negative pathogens producing a broad array of extended-spectrum ,-lactamases. Tigecycline is the first example of a new class of glycylcyclines with activity against a wide range of clinically important Gram-negative pathogens. Tigecycline has potent antimicrobial activity, and has been associated with an excellent therapeutic response in animal infection models and recently reported clinical trials, which reflect the effectiveness of tigecycline against pathogens causing intra-abdominal, skin and soft-tissue infections, including susceptible or multidrug-resistant strains of most Enterobacteriaceae, as well as anaerobic pathogens. [source] Supernatants of Pseudomonas aeruginosa induce the Pseudomonas -specific antibiotic elafin in human keratinocytesEXPERIMENTAL DERMATOLOGY, Issue 4 2003Ulf Meyer-Hoffert Abstract: Elafin is a skin-derived serine-protease inhibitor. It is thought to be important to prevent human leukocyte elastase-mediated tissue damage and might play an important role in maintaining the integrity of the human epidermis. Recent studies have provided evidence for an antimicrobial activity of elafin against P. aeruginosa. As gram-negative infections typically occur in barrier-disrupted skin we were interested to determine whether supernatants of the gram-negative bacteria P. aeruginosa and Escherichia coli were capable of inducing elafin expression. Supernatants of various P. aeruginosa strains stimulated elafin mRNA-expression and protein release, whereas supernatants of E. coli did not induce elafin expression. In non-differentiated cells the relative increase of elafin mRNA was much higher (100-fold) than in differentiated cells (sixfold), although the latter exhibited higher constitutive mRNA-expression (150-fold). However, concentrations of secreted elafin were similar in differentiated and non-differentiated cells after stimulation. We could not confirm a bactericidal effect against P. aeruginosa as described previously but observed that its growth was inhibited as demonstrated for different strains in liquid cultures. Growth of E. coli was not affected by elafin. In conclusion, the data presented in this paper suggest that elafin represents an innate immune response factor induced by secreted products of P. aeruginosa. Besides its elastase inhibitory potency elafin is an antimicrobial agent against P. aeruginosa. [source] | ||||||||||