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Li J Nation RL Milne RW Turnidge JD Coulthard K 《International journal of antimicrobial agents》2005,25(1):11-25
Infections caused by multi-resistant Gram-negative bacteria, particularly Pseudomonas aeruginosa, are increasing worldwide. In patients with cystic fibrosis (CF), resistance in P. aeruginosa to numerous anti-pseudomonal agents is becoming common. The absence since 1995, of new substances active against resistant Gram-negative bacteria, has caused increasing concern. Colistin, an old antibiotic also known as polymyxin E, has attracted more interest recently because of its significant activity against multi-resistant P. aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae, and the low resistance rates to it. Because its use as an anti-pseudomonal agent was displaced by the potentially less toxic aminoglycosides in 1970s, our knowledge of this drug is limited. However, there has been a significant recent increase in the data gathered on colistin, focussing on its chemistry, antibacterial activity, mechanism of action and resistance, pharmacokinetics, pharmacodynamics and new clinical application. It is likely that colistin will be an important antimicrobial option against multi-resistant Gram-negative bacteria, for some years to come. 相似文献
198.
Wierenga CE Stricker NH McCauley A Simmons A Jak AJ Chang YL Nation DA Bangen KJ Salmon DP Bondi MW 《Neuropsychologia》2011,49(3):392-404
Word retrieval deficits are common in Alzheimer's disease (AD) and are thought to reflect a degradation of semantic memory. Yet, the nature of semantic deterioration in AD and the underlying neural correlates of these semantic memory changes remain largely unknown. We examined the semantic memory impairment in AD by investigating the neural correlates of category knowledge (e.g., living vs. nonliving) and featural processing (global vs. local visual information). During event-related fMRI, 10 adults diagnosed with mild AD and 22 cognitively normal (CN) older adults named aloud items from three categories for which processing of specific visual features has previously been dissociated from categorical features. Results showed widespread group differences in the categorical representation of semantic knowledge in several language-related brain areas. For example, the right inferior frontal gyrus showed selective brain response for nonliving items in the CN group but living items in the AD group. Additionally, the AD group showed increased brain response for word retrieval irrespective of category in Broca's homologue in the right hemisphere and rostral cingulate cortex bilaterally, which suggests greater recruitment of frontally mediated neural compensatory mechanisms in the face of semantic alteration. 相似文献
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Bergen PJ Forrest A Bulitta JB Tsuji BT Sidjabat HE Paterson DL Li J Nation RL 《Antimicrobial agents and chemotherapy》2011,55(11):5134-5142
The use of combination antibiotic therapy may be beneficial against rapidly emerging resistance in Pseudomonas aeruginosa. The aim of this study was to systematically investigate in vitro bacterial killing and resistance emergence with colistin alone and in combination with imipenem against multidrug-resistant (MDR) P. aeruginosa. Time-kill studies were conducted over 48 h using 5 clinical isolates and ATCC 27853 at two inocula (~10(6) and ~10(8) CFU/ml); MDR, non-MDR, and colistin-heteroresistant and -resistant strains were included. Nine colistin-imipenem combinations were investigated. Microbiological response was examined by log changes at 6, 24, and 48 h. Colistin combined with imipenem at clinically relevant concentrations increased the levels of killing of MDR and colistin-heteroresistant isolates at both inocula. Substantial improvements in activity with combinations were observed across 48 h with all colistin concentrations at the low inoculum and with colistin at 4× and 16× MIC (or 4 and 32 mg/liter) at the high inoculum. Combinations were additive or synergistic against imipenem-resistant isolates (MICs, 16 and 32 mg/liter) at the 10(6)-CFU inoculum in 9, 11, and 12 of 18 cases (i.e., 9 combinations across 2 isolates) at 6, 24, and 48 h, respectively, and against the same isolates at the 10(8)-CFU inoculum in 11, 7, and 8 cases, respectively. Against a colistin-resistant strain (MIC, 128 mg/liter), combinations were additive or synergistic in 9 and 8 of 9 cases at 24 h at the 10(6)- and 10(8)-CFU inocula, respectively, and in 5 and 7 cases at 48 h. This systematic study provides important information for optimization of colistin-imipenem combinations targeting both colistin-susceptible and colistin-resistant subpopulations. 相似文献
200.
Melatonin attenuates colistin-induced nephrotoxicity in rats 总被引:1,自引:0,他引:1
Colistin-induced nephrotoxicity is a dose-limiting adverse effect when colistin is used against Gram-negative pathogens. This study examined the nephroprotective effect of melatonin against colistin in rats. Rats (n = 7 per group) were treated intravenously twice daily with saline, colistin (at increasing doses from 0.5 to 4.0 mg/kg), melatonin (5 mg/kg), or both melatonin and colistin for 7 days. The severity of renal alteration was examined both biochemically and histologically. The effect of coadministration of melatonin on colistin pharmacokinetics was investigated. Significantly lower urinary N-acetyl-β-d-glucosaminidase excretion was observed from day 1 in the colistin-melatonin group compared to the colistin group (P < 0.0001). Plasma creatinine increased significantly (P = 0.023) only in the colistin group on day 6. Significant histological abnormalities (P < 0.0001) were detected only in the kidneys of the colistin group. Melatonin altered colistin pharmacokinetics; the total body clearance in the colistin-melatonin group (1.82 ± 0.26 ml/min/kg) was lower than in the colistin group (4.28 ± 0.93 ml/min/kg). This is the first study demonstrating the protective effect of melatonin against colistin-induced nephrotoxicity, which indicates that colistin-induced nephrotoxicity is mediated through oxidative stress. It also highlights the potential of coadministering an antioxidant to widen the therapeutic window of this very important last-line antibiotic. 相似文献