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Colistin methanesulfonate and colistin pharmacokinetics in critically ill patients receiving continuous venovenous hemodiafiltration. Antimicrob Agents Chemother 2012; 57:668-71. [PMID: 23147733 DOI: 10.1128/aac.00985-12] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This report describes the pharmacokinetics of colistin methanesulfonate (CMS) and colistin in five intensive care unit patients receiving continuous venovenous hemodiafiltration. For CMS, the mean maximum concentration of drug in plasma (C(max)) after the fourth dose was 6.92 mg/liter and total clearance (CL) 8.23 liters/h. For colistin, the mean concentration was 0.92 mg/liter and CL/metabolized fraction (f(m)) 18.91 liters/h. Colistin concentrations were below the current MIC breakpoints, and the area under the concentration-time curve for the free, unbound fraction of the drug over 24 h in the steady state divided by the MIC (fAUC/MIC) was lower than recommended, suggesting that a dosage regimen of 160 mg CMS every 8 h (q8h) is inadequate.
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202
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Sun Y, Wilkinson BJ, Standiford TJ, Akinbi HT, O'Riordan MXD. Fatty acids regulate stress resistance and virulence factor production for Listeria monocytogenes. J Bacteriol 2012; 194:5274-84. [PMID: 22843841 PMCID: PMC3457240 DOI: 10.1128/jb.00045-12] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 07/09/2012] [Indexed: 12/15/2022] Open
Abstract
Fatty acids (FAs) are the major structural component of cellular membranes, which provide a physical and chemical barrier that insulates intracellular reactions from environmental fluctuations. The native composition of membrane FAs establishes the topological and chemical parameters for membrane-associated functions and is therefore modulated diligently by microorganisms especially in response to environmental stresses. However, the consequences of altered FA composition during host-pathogen interactions are poorly understood. The food-borne pathogen Listeria monocytogenes contains mostly saturated branched-chain FAs (BCFAs), which support growth at low pH and low temperature. In this study, we show that anteiso-BCFAs enhance bacterial resistance against phagosomal killing in macrophages. Specifically, BCFAs protect against antimicrobial peptides and peptidoglycan hydrolases, two classes of phagosome antimicrobial defense mechanisms. In addition, the production of the critical virulence factor, listeriolysin O, was compromised by FA modulation, suggesting that FAs play a key role in virulence regulation. In summary, our results emphasize the significance of FA metabolism, not only in bacterial virulence regulation but also in membrane barrier function by providing resistance against host antimicrobial stress.
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Affiliation(s)
- Yvonne Sun
- University of Michigan Medical School, Department of Microbiology and Immunology, Ann Arbor, Michigan, USA.
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203
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May I, Abu-Khdeir M, Blackwood RA. An usual approach to treatment of a case of multidrug resistance Pseudomonas aeruginosa peritonitis: parenteral and intraperitoneal aminoglycosides and parenteral colistin. Infect Dis Rep 2012; 4:e36. [PMID: 24470950 PMCID: PMC3892633 DOI: 10.4081/idr.2012.e36] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 06/18/2012] [Accepted: 06/20/2012] [Indexed: 11/23/2022] Open
Abstract
Infections caused by Pseudomonas aeruginosa are becoming more common and increasingly more difficult to treat due to the continued development of drug resistance. While sensitivity to colistin (polymyxin E) is well known, it is frequently avoided due to concerns of nephrotoxicity. Reported here is a case of a multi-drug resistance pseudomonal typhlitis, bacteremia and pleural cavity infection that required significant intensive care, and serial abdominal washouts. Intra-peritoneal tobramycin in combination with broad-spectrum intravenous antibiotics including colistin were used. Several instillations of tobramycin into the abdominal cavity along with concomitant IV administration of colistin, ceftazidime and tobramycin and per os colistin, tobramycin and nystatin resulted in the clearance of the pseudomonal infection without any evidence of toxicity from the treatment. Intra-abdominal tobramycin with parenteral colistin therapy can be used in complicated clinical settings with appropriate nephroprotection.
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Affiliation(s)
- Ian May
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Maha Abu-Khdeir
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Roland Alexander Blackwood
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI, USA
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204
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Bergen PJ, Landersdorfer CB, Zhang J, Zhao M, Lee HJ, Nation RL, Li J. Pharmacokinetics and pharmacodynamics of 'old' polymyxins: what is new? Diagn Microbiol Infect Dis 2012; 74:213-23. [PMID: 22959816 DOI: 10.1016/j.diagmicrobio.2012.07.010] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 07/12/2012] [Accepted: 07/23/2012] [Indexed: 12/21/2022]
Abstract
'Old' colistin and polymyxin B are increasingly used as last-line therapy against multidrug-resistant Gram-negative bacteria Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae. For intravenous administration, colistin is dosed as its inactive prodrug colistin methanesulfonate (sodium), while polymyxin B is used as its sulfate (active antibacterial). Over the last decade, significant progress has been made in understanding their chemistry, pharmacokinetics (PK), and pharmacodynamics (PD). The first scientifically based dosing suggestions are now available for colistin methanesulfonate to generate a desired target steady-state plasma concentration of formed colistin in various categories of critically ill patients. As simply increasing polymyxin dosage regimens is not an option for optimizing their PK/PD due to nephrotoxicity, combination therapy with other antibiotics has great potential to maximize the efficacy of polymyxins while minimizing emergence of resistance. We must pursue rational approaches to the use of polymyxins and other existing antibiotics through the application of PK/PD principles.
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Affiliation(s)
- Phillip J Bergen
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
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205
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Fitzpatrick MA, Esterly JS, Postelnick MJ, Sutton SH. Successful treatment of extensively drug-resistant Acinetobacter baumannii peritoneal dialysis peritonitis with intraperitoneal polymyxin B and ampicillin-sulbactam. Ann Pharmacother 2012; 46:e17. [PMID: 22811349 DOI: 10.1345/aph.1r086] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To describe a case of extensively drug-resistant (XDR) Acinetobacter baumannii peritoneal dialysis (PD)-associated peritonitis successfully treated with combination antibiotics, including intraperitoneal polymyxin B, with retention of the catheter. CASE SUMMARY A 54-year-old woman with end-stage renal disease receiving chronic PD and recent antibiotic and hospital exposure presented with abdominal pain, nausea, and vomiting. She was found to have XDR A. baumannii PD peritonitis. Treatment was initiated with intravenous and intraperitoneal ampicillin-sulbactam, followed by the addition of intraperitoneal polymyxin B based on susceptibilities. The patient recovered without the need for catheter removal or switch to hemodialysis. DISCUSSION The frequency of XDR A. baumannii as a nosocomial pathogen is increasing, and polymyxins are being used more often as part of combination therapy for infections caused by this organism. Neither XDR A. baumannii PD peritonitis nor the use of intraperitoneal polymyxin B has been well described. In our patient, intraperitoneal dosing of polymyxin B was determined based on limited published pharmacokinetic and pharmacodynamic data. CONCLUSIONS A case of XDR A. baumannii PD peritonitis was successfully treated with combination antibiotic therapy, including intraperitoneal polymyxin B, without major complications.
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Affiliation(s)
- Margaret A Fitzpatrick
- Division of Infectious Diseases, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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206
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Role of heme oxygenase-1 in polymyxin B-induced nephrotoxicity in rats. Antimicrob Agents Chemother 2012; 56:5082-7. [PMID: 22802257 DOI: 10.1128/aac.00925-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Polymyxin B (PMB) is a cationic polypeptide antibiotic with activity against multidrug-resistant Gram-negative bacteria. PMB-induced nephrotoxicity consists of direct toxicity to the renal tubules and the release of reactive oxygen species (ROS) with oxidative damage. This study evaluated the nephroprotective effect of heme oxygenase-1 (HO-1) against PMB-induced nephrotoxicity in rats. Adult male Wistar rats, weighing 286 ± 12 g, were treated intraperitoneally once a day for 5 days with saline, hemin (HO-1 inducer; 10 mg/kg), zinc protoporphyrin (ZnPP) (HO-1 inhibitor; 50 μmol/kg, administered before PMB on day 5), PMB (4 mg/kg), PMB plus hemin, and PMB plus ZnPP. Renal function (creatinine clearance, Jaffe method), urinary peroxides (ferrous oxidation of xylenol orange version 2 [FOX-2]), urinary thiobarbituric acid-reactive substances (TBARS), renal tissue thiols, catalase activity, and renal tissue histology were analyzed. The results showed that PMB reduced creatinine clearance (P < 0.05), with an increase in urinary peroxides and TBARS. The PMB toxicity caused a reduction in catalase activity and thiols (P < 0.05). Hemin attenuated PMB nephrotoxicity by increasing the catalase antioxidant activity (P < 0.05). The combination of PMB and ZnPP incremented the fractional interstitial area of renal tissue (P < 0.05), and acute tubular necrosis in the cortex area was also observed. This is the first study demonstrating the protective effect of HO-1 against PMB-induced nephrotoxicity.
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207
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Abstract
Persisters are dormant phenotypic variants of regular cells that are tolerant to antibiotics and play an important role in recalcitrance of chronic infections to therapy. Persisters can be produced stochastically in a population untreated with antibiotics. At the same time, a deterministic component of persister formation has also been documented in a population of cells with DNA damaged by fluoroquinolone treatment. Expression of the SOS response under these conditions induces formation of persisters by increasing expression of the TisB toxin. This suggests that other stress responses may also contribute to persister formation. Of particular interest is oxidative stress that pathogens encounter during infection. Activated macrophages produce reactive oxygen and nitrogen species which induce the SoxRS and OxyR regulons. Genes controlled by these regulons deactivate the oxidants and promote repair. We examined the ability of oxidative stress induced by paraquat (PQ) to affect persister formation. Preincubation of cells with PQ produced a dramatic increase in the number of persisters surviving challenge with fluoroquinolone antibiotics. PQ did not affect killing by kanamycin or ampicillin. Persisters in a culture treated with PQ that survived a challenge with a fluoroquinolone were also highly tolerant to other antibiotics. PQ induces SoxRS, which in turn induces expression of the AcrAB-TolC multidrug-resistant (MDR) pump. Fluoroquinolones are extruded by this MDR pump, and the effect of PQ on antibiotic tolerance was largely abolished in a mutant that was defective in the pump. It appears that PQ, acting through AcrAB-TolC, reduces the concentration of fluoroquinolones in the cells. This allows a larger fraction of cells to become persisters in the presence of a fluoroquinolone. Analysis of a lexA3 mutant indeed showed a dependence of persister induction under these conditions on SOS. These findings show that induction of a classical resistance mechanism, MDR efflux, by oxidative stress leads to an increase in multidrug-tolerant persister cells.
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208
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Florescu DF, Qiu F, McCartan MA, Mindru C, Fey PD, Kalil AC. What is the efficacy and safety of colistin for the treatment of ventilator-associated pneumonia? A systematic review and meta-regression. Clin Infect Dis 2012; 54:670-80. [PMID: 22322268 DOI: 10.1093/cid/cir934] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Experience with intravenous and aerosolized forms of colistin for the treatment of ventilator-associated pneumonia (VAP) in patients without cystic fibrosis is limited. We aimed to assess the safety and efficacy of colistin for the treatment of VAP. METHODS We searched MEDLINE and Cochrane Database of Systematic Reviews for studies comparing colistin vs other antibiotics for treatment of VAP in patients without cystic fibrosis. QUOROM guidelines were followed, the I(2) method was used for heterogeneity, and a random-effects model for odds ratio (OR) estimates. RESULTS Six controlled studies met the inclusion criteria. Clinical response did not differ significantly between colistin and control groups (OR, 1.14; 95% confidence interval [CI], .74-1.77; P = .56; I(2) = 0%). The efficacy of colistin was independent of study design (prospective OR, 0.89 [95% CI, .48-1.66; P = .71; I(2) = 0%]; retrospective OR, 1.45 [95% CI, .79-2.68; P = .23; I(2) = 0%]); randomized trials OR, 0.86 [95% CI, .43-1.74; P = .68; I(2) = 0%]). There was no indication of a significant change in clinical response after controlling for concomitant antibiotic treatment (intercept, 0.121; slope, 0.0315; P = .95). Treatment with colistin vs controls did not affect hospital mortality (OR, 0.92; 95% CI, .50-1.67; P = .78; I(2) = 34.59%) or nephrotoxicity (OR, 1.14; 95% CI, .59-2.20; P = .69; I(2) = 0%). Fourteen single-arm studies have been analyzed, and the results were in concordance with the findings of the controlled studies. CONCLUSIONS Our results suggest that colistin may be as safe and as efficacious as standard antibiotics for the treatment of VAP.
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Affiliation(s)
- Diana F Florescu
- Infectious Diseases Division, Nebraska Medical Center, Omaha, NE 68198-5400, USA.
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209
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Doshi NM, Mount KL, Murphy CV. Nephrotoxicity associated with intravenous colistin in critically ill patients. Pharmacotherapy 2012; 31:1257-64. [PMID: 22122186 DOI: 10.1592/phco.31.12.1257] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
STUDY OBJECTIVES To determine the frequency of nephrotoxicity associated with colistin therapy by using a standardized definition and to identify risk factors for colistin-induced nephrotoxicity in critically ill patients. DESIGN Single-center, retrospective cohort analysis. SETTING University-affiliated tertiary care center. PATIENTS Forty-nine adults admitted to an intensive care unit who received intravenous colistin for at least 48 hours between July 2007 and July 2009. MEASUREMENTS AND MAIN RESULTS Nephrotoxicity was determined by using the standardized RIFLE criteria: risk, injury, failure, loss, and end-stage renal disease. Patients who had end-stage renal disease or required renal replacement therapy before initiation of colistin were excluded. Of the 49 patients included in the analysis, 15 (31%) developed nephrotoxicity, and only two patients (4%) had irreversible cases. Patients with chronic kidney disease (40% in the group with nephrotoxicity vs 3% in the group without nephrotoxicity, p=0.002) and hypertension (87% vs 56%, p=0.037) at baseline had a higher risk of developing nephrotoxicity. In addition, patients with nephrotoxicity were more likely to have received intravenous contrast material (33% vs 0%, p=0.002). The risk of developing nephrotoxicity was 6.5 times higher in patients who had been given at least two concomitant nephrotoxic agents compared with no other nephrotoxic agents (p=0.034). CONCLUSION The frequency and severity of colistin-induced nephrotoxicity in critically ill patients was consistent with previous reports in non-critically ill patients. Most cases of nephrotoxicity demonstrated in this study were mild and reversible. Patients receiving colistin therapy who have hypertension or chronic kidney disease should be monitored closely, and administration of additional nephrotoxic agents should be avoided in all patients when possible. Large, prospective trials are warranted to confirm these results.
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Affiliation(s)
- Neha M Doshi
- Department of Pharmacy, The Ohio State University Medical Center, Columbus, Ohio 43210, USA
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210
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Ntwasa M, Goto A, Kurata S. Coleopteran antimicrobial peptides: prospects for clinical applications. Int J Microbiol 2012; 2012:101989. [PMID: 22500175 PMCID: PMC3303552 DOI: 10.1155/2012/101989] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 11/02/2011] [Accepted: 12/05/2011] [Indexed: 12/20/2022] Open
Abstract
Antimicrobial peptides (AMPs) are activated in response to septic injury and have important roles in vertebrate and invertebrate immune systems. AMPs act directly against pathogens and have both wound healing and antitumor activities. Although coleopterans comprise the largest and most diverse order of eukaryotes and occupy an earlier branch than Drosophila in the holometabolous lineage of insects, their immune system has not been studied extensively. Initial research reports, however, indicate that coleopterans possess unique immune response mechanisms, and studies of these novel mechanisms may help to further elucidate innate immunity. Recently, the complete genome sequence of Tribolium was published, boosting research on coleopteran immunity and leading to the identification of Tribolium AMPs that are shared by Drosophila and mammals, as well as other AMPs that are unique. AMPs have potential applicability in the development of vaccines. Here, we review coleopteran AMPs, their potential impact on clinical medicine, and the molecular basis of immune defense.
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Affiliation(s)
- Monde Ntwasa
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits 2050, South Africa
| | - Akira Goto
- Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Shoichiro Kurata
- Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai 980-8578, Japan
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211
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Incidence and predictors of nephrotoxicity associated with intravenous colistin in overweight and obese patients. Antimicrob Agents Chemother 2012; 56:2392-6. [PMID: 22371891 DOI: 10.1128/aac.00028-12] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Intravenous colistin is used to treat resistant Gram-negative infections and is associated with nephrotoxicity. In overweight and obese adults, a paucity of data exists regarding the incidence and predictors of such toxicity. A retrospective nested case-control study was performed over 35 months for patients receiving intravenous colistin for ≥ 72 h with a body mass index (BMI) of ≥ 25 kg/m(2). The objective was to investigate the incidence and predictors of nephrotoxicity. Severity of acute kidney injury was defined by RIFLE (risk, injury, failure, loss, and end-stage kidney disease) criteria. Dosing and mortality were secondarily investigated. Forty-two patients met the inclusion criteria, and 20 (48%) developed nephrotoxicity. Patients with toxicity were in the risk (15%), injury (5%), and failure (80%) categories based on RIFLE criteria. A logistic regression model identified four predictors of colistin-associated nephrotoxicity: a BMI of ≥ 31.5 kg/m(2) (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.15 to 8.35), diabetes (OR, 2.11; 95% CI, 0.84 to 5.29), the length of hospitalization in days prior to receipt of colistin (OR, 1.04; 95% CI, 0.99 to 1.08), and age (OR, 1.08; 95% CI, 1.00 to 1.17). Among all of the patients, dosing based on the actual body weight and excessive dosing due to the use of the actual body weight were frequent at 64% and 92%, respectively. The 30-day all-cause in-hospital mortality rate was 40% in the toxicity group and 14% in the nontoxicity group (P = 0.14). Patients receiving intravenous colistin should be monitored for nephrotoxicity, especially when the BMI exceeds 31.5 kg/m(2). Prospective, randomized, controlled trials are warranted to further examine nephrotoxicity incidence and predictors and appropriate dosing strategies in this population.
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212
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Isolation of a Paenibacillus sp. strain and structural elucidation of its broad-spectrum lipopeptide antibiotic. Appl Environ Microbiol 2012; 78:3156-65. [PMID: 22367082 DOI: 10.1128/aem.07782-11] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
This research was initiated to search for novel antimicrobial compounds produced by food or environmental microorganisms. A new bacterial strain, designated OSY-SE, which produces a unique and potent antimicrobial agent was isolated from soil. The isolate was identified as a Paenibacillus sp. through cultural, biochemical, and genetic analyses. An antimicrobial compound was extracted from Paenibacillus OSY-SE with acetonitrile and purified using liquid chromatography. After analyses by mass spectrometry (MS) and nuclear magnetic resonance (NMR), the antimicrobial compound was determined to be a cyclic lipopeptide consisting of a C(15) fatty acyl (FA) chain and 13 amino acids. The deduced sequence is FA-Orn-Val-Thr-Orn-Ser-Val-Lys-Ser-Ile-Pro-Val-Lys-Ile. The carboxyl-terminal Ile is connected to Thr by ester linkage. The new compound, designated paenibacterin, showed antagonistic activities against most Gram-positive and Gram-negative bacteria tested, including Listeria monocytogenes, methicillin-resistant Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella enterica serovar Typhimurium. Paenibacterin is resistant to trypsin, lipase, α-glucosidase, and lysozyme. Its antimicrobial activity was lost after digestion by pronase and polymyxin acylase. Paenibacterin is readily soluble in water and fairly stable to exposure to heat and a wide range of pH values. The new isolate and its antimicrobial agent are being investigated for usefulness in food and medical applications.
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213
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Ahmed H, Elbarbry F, Clark B. Mixed Micellar Electrokinetic Chromatographic Analysis of Colistin, Polypeptide Antibiotic, Using Laser-Induced Fluorescence Detection. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/ajac.2012.33031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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214
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Balaji V, Jeremiah SS, Baliga PR. Polymyxins: Antimicrobial susceptibility concerns and therapeutic options. Indian J Med Microbiol 2011; 29:230-42. [PMID: 21860102 DOI: 10.4103/0255-0857.83905] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The increasing prevalence of multidrug-resistant nosocomial pathogens such as Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae poses a great challenge to the treating physicians. The paucity of newer effective antimicrobials has led to renewed interest in the polymyxin group of drugs, as a last resort for treatment of gram-negative bacterial infections. There is a dearth of information on the pharmacological properties of colistin, leading to difficulties in selecting the right dose, dosing interval, and route of administration for treatment, especially in critically-ill patients. The increasing use of colistin over the last few years necessitates the need for accurate and reliable in vitro susceptibility testing methods. Development of heteroresistant strains as a result of colistin monotherapy is also a growing concern. There is a compelling need from the clinicians to provide options for probable and possible colistin combination therapy for multidrug-resistant bacterial infections in the ICU setting. Newer combination drug synergy determination tests are being developed and reported. There are no standardized recommendations from antimicrobial susceptibility testing reference agencies for the testing and interpretation of these drug combinations. Comparison and analysis of these reported methodologies may help to understand and assist the microbiologist to choose the best method that produces accurate results at the earliest. This will help clinicians to select the appropriate combination therapy. In this era of multidrug resistance it is important for the microbiology laboratory to be prepared, by default, to provide timely synergistic susceptibility results in addition to routine susceptibility, if warranted. Not as a favour or at request, but as a responsibility.
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Affiliation(s)
- V Balaji
- Department of Clinical Microbiology, Christian Medical College, Vellore - 632 004, Tamil Nadu, India.
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215
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Yousef JM, Chen G, Hill PA, Nation RL, Li J. Ascorbic acid protects against the nephrotoxicity and apoptosis caused by colistin and affects its pharmacokinetics. J Antimicrob Chemother 2011; 67:452-9. [PMID: 22127588 DOI: 10.1093/jac/dkr483] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES The use of colistin in the treatment of life-threatening Gram-negative infections is associated with a high rate of nephrotoxicity that is dose limiting. This study aimed to examine the nephroprotective effect of ascorbic acid against colistin-induced nephrotoxicity. METHODS Rats were treated intravenously twice daily with saline, colistin (cumulative dose of 36.5 mg/kg), a combination of ascorbic acid (50 or 200 mg/kg) and colistin, or ascorbic acid (200 mg/kg) over 7 days. Colistin-induced apoptosis was examined in rats over 5 days and in vitro using rat renal proximal tubular cells NRK-52E over 24 h with and without ascorbic acid. The effect of co-administered ascorbic acid on colistin pharmacokinetics was investigated. RESULTS The 24 h urinary excretion of N-acetyl-β-D-glucosaminidase, a sensitive marker for tubular damage, was significantly lower (P < 0.0001) in the colistin/ascorbic acid 200 mg/kg group. Significant histological abnormalities (P < 0.01) were detected only in the kidneys of the colistin group, which also had the highest percentage (30.6 ± 7.8%) of apoptotic cells (P < 0.005). In the cell culture studies, the percentage of apoptotic cells was significantly higher in the presence of 0.1 mM colistin alone (51.8 ± 2.0%; P < 0.0001) than in the presence of ascorbic acid, which decreased the apoptotic effect in a concentration-dependent manner. Ascorbic acid (200 mg/kg) altered colistin pharmacokinetics, as the total body clearance decreased from 3.78 ± 0.36 mL/min/kg (colistin group) to 2.46 ± 0.57 mL/min/kg (P = 0.0024). CONCLUSIONS This is the first study demonstrating the protective effect of ascorbic acid against colistin-induced nephrotoxicity and tubular apoptosis. Co-administration of ascorbic acid has the potential to increase the therapeutic index of colistin.
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Affiliation(s)
- Jumana M Yousef
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
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216
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Naghmouchi K, Le Lay C, Baah J, Drider D. Antibiotic and antimicrobial peptide combinations: synergistic inhibition of Pseudomonas fluorescens and antibiotic-resistant variants. Res Microbiol 2011; 163:101-8. [PMID: 22172555 DOI: 10.1016/j.resmic.2011.11.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 11/04/2011] [Indexed: 10/15/2022]
Abstract
Variants resistant to penicillin G (RvP), streptomycin (RvS), lincomycin (RvL) and rifampicin (RvR) were developed from a colistin-sensitive isolate of Pseudomonas fluorescens LRC-R73 (P. fluorescens). Cell fatty acid composition, K(+) efflux and sensitivity to antimicrobial peptides (nisin Z, pediocin PA-1/AcH and colistin) alone or combined with antibiotics were determined. P. fluorescens was highly sensitive to kanamycin, tetracycline and chloramphenicol at minimal inhibitory concentrations of 0.366, 0.305 and 0.732 μg/ml respectively. P. fluorescens, RvP, RvS, RvL and RvR were resistant to nisin Z and pediocin PA-1/AcH at concentrations ≥100 μg/ml but sensitive to colistin at 0.076, 0.043, 0.344, 0.344 and 0.258 μg/ml respectively. A synergistic inhibitory effect (FICI ≤0.5) was observed when resistant variants were treated with peptide/antibiotic combinations. No significant effect on K(+) efflux from the resistant variants in the presence of antibiotics or peptides alone or combined was observed. The proportion of C16:0 was significantly higher in antibiotic-resistant variants than in the parent strain, accounting for 32.3%, 46.49%, 43.3%, 40.1% and 44.1% of the total fatty acids in P. fluorescens, RvP, RvS, RvL and RvR respectively. Combination of antibiotics with antimicrobial peptides could allow reduced use of antibiotics in medical applications and could help slow the emergence of bacteria resistant to antibiotics.
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Affiliation(s)
- Karim Naghmouchi
- Lethbridge Research Center, Agricultureg and Agri-Food Canada, Lethbridge, AB, Canada.
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217
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Rodrigues ACS, Chang MR, Nóbrega GD, Rodrigues MS, Carvalho NCP, Gomes BG, Almeida DLD, Carvalho KR, Asensi MD. Metallo-β-lactamase and genetic diversity of Pseudomonas aeruginosa in intensive care units in Campo Grande, MS, Brazil. Braz J Infect Dis 2011; 15:195-9. [PMID: 21670916 DOI: 10.1016/s1413-8670(11)70174-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Accepted: 12/21/2010] [Indexed: 10/27/2022] Open
Abstract
Infection by Pseudomonas aeruginosa has spread worldwide, with limited options for treatment. The purpose of this study was to investigate metallo-β-lactamase-producing P. aeruginosa strains and compare their genetic profile using samples collected from patients in intensive care units. Forty P. aeruginosa strains were isolated from two public hospitals in Campo Grande, Mato Grosso do Sul State, from January 1st, 2007 to June 31st, 2008. Profiles of antimicrobial susceptibility were determined using the agar diffusion method. Metallo-β-lactamase was investigated using the double-disk diffusion test and PCR. Molecular typing was performed by pulsed-field gel electrophoresis (PFGE). Respiratory and urinary tracts were the most common isolation sites. Of the 40 samples tested, 72.5% (29/40) were resistant to ceftazidime and 92.5% (37/40) to imipenem, whereas 65% (26/40) were resistant to both antimicrobials. Fifteen pan-resistant samples were found. Five percent (2/40) of samples were positive for metallo-β-lactamase on the phenotype test. No metallo-β-lactamase subtype was detected by PCR. Macrorestriction analysis revealed 14 distinct genetic patterns. Based on the superior accuracy of PCR, it can be inferred that P. aeruginosa isolates from the investigated hospitals have alternative mechanisms of carbapenem resistance. The results also suggest clonal spread of P. aeruginosa between the studied hospitals.
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Affiliation(s)
- Ana Claudia Souza Rodrigues
- Health and Development Post-graduation Program, Central-West Region, Universidade Federal de Mato Grosso do Sul, MS, Brazil.
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218
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Hammami S, Boutiba-Ben Boubaker I, Ghozzi R, Saidani M, Amine S, Ben Redjeb S. Nosocomial outbreak of imipenem-resistant Pseudomonas aeruginosa producing VIM-2 metallo-β-lactamase in a kidney transplantation unit. Diagn Pathol 2011; 6:106. [PMID: 22035284 PMCID: PMC3223140 DOI: 10.1186/1746-1596-6-106] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 10/28/2011] [Indexed: 01/05/2023] Open
Abstract
Background Twenty four non replicate imipenem resistant P. aeruginosa were isolated between January and November 2008, in the kidney transplantation unit of Charles Nicolle Hospital of Tunis (Tunisia). This study was conducted in order to establish epidemiological relationship among them and to identify the enzymatic mechanism involved in imipenem resistance. Methods Analysis included antimicrobial susceptibility profile, phenotypic (imipenem-EDTA synergy test) and genotypic detection of metallo-β-lactamase (MBL) (PCR), O-serotyping and pulsed-field gel electrophoresis. Results All strains showed a high level of resistance to all antimicrobials tested except to colistin. The presence of MBL showed concordance between phenotypic and genotypic methods. Sixteen isolates were identified as VIM-2 MBL-producers and 13 of them were serotype O4 and belonged to a single pulsotype (A). Conclusions This study describes an outbreak of VIM-2-producing P. aeruginosa in a kidney transplantation unit. Clinical spread of blaVIM-2 gene is a matter of great concern for carbapenem resistance in Tunisia.
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Affiliation(s)
- S Hammami
- Laboratoire Résistance aux Antimicrobiens, Faculté de Médecine de Tunis Université Elmanar, 15 Rue Djebel Akhdhar-La Rabta-1007 Bab Saâdoun-Tunis, Tunisie.
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219
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Maekawa LE, Valera MC, Oliveira LDD, Carvalho CAT, Koga-Ito CY, Jorge AOC. In vitro evaluation of the action of irrigating solutions associated with intracanal medications on Escherichia coli and its endotoxin in root canals. J Appl Oral Sci 2011; 19:106-12. [PMID: 21552710 PMCID: PMC4243747 DOI: 10.1590/s1678-77572011000200005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 02/16/2010] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE The purpose of this study was to evaluate the efficacy of auxiliary chemical substances and intracanal medications on Escherichia coli and its endotoxin in root canals. MATERIAL AND METHODS Teeth were contaminated with a suspension of E. coli for 14 days and divided into 3 groups according to the auxiliary chemical substance used: G1) 2.5% sodium hypochlorite (NaOCl); G2) 2% chlorhexidine gel (CLX); G3) pyrogen-free solution. After, these groups were subdivided according to the intracanal medication (ICM): A) Calcium hydroxide paste (Calen®), B) polymyxin B, and C) Calcium hydroxide paste+2% CLX gel. For the control group (G4), pyrogen-free saline solution was used without application of intracanal medication. Samples of the root canal content were collected immediately after biomechanical preparation (BMP), at 7 days after BMP, after 14 days of intracanal medication activity, and 7 days after removal of intracanal medication. The following aspects were evaluated for all collections: a) antimicrobial activity; b) quantification of endotoxin by the Limulus Amebocyte Lysate test (LAL). Results were analyzed by the Kruskal-Wallis and Dunn's tests at 5% significance level. RESULTS The 2.5% NaOCl and CLX were able to eliminate E. coli from root canal lumen and reduced the amount of endotoxin compared to saline. CONCLUSIONS It was concluded that 2.5% NaOCl and CLX were effective in eliminating E. coli. Only the studied intracanal medications were to reduce the amount of endotoxin present in the root canals, regardless of the irrigant used.
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Affiliation(s)
- Lilian Eiko Maekawa
- Department of Restorative Dentistry, São Paulo State University, São José dos Campos, SP, Brazil.
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220
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Bhunia A, Bhattacharjya S. Mapping residue-specific contacts of polymyxin B with lipopolysaccharide by saturation transfer difference NMR: insights into outer-membrane disruption and endotoxin neutralization. Biopolymers 2011; 96:273-87. [PMID: 20683937 DOI: 10.1002/bip.21530] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
High-resolution interactions studies of molecules with lipopolysaccharide (LPS) or endotoxin are important for health, diseases and environment. LPS is the major constituent of the outer layer of the outer membrane of the gram-negative bacteria. LPS provides an efficient barrier against permeation of variety of compounds including antibacterial agents and antimicrobial peptides. In the intensive care units, LPS is known for the fatal septic shock syndromes. Because of LPS toxicity, high affinity LPS sensors are sought-after for the assessment of the quality of water and pharmaceutical products. Therefore, elucidation of binding epitopes of LPS interacting molecules would be vital for the development of antimicrobial, antiendotoxic molecules. Polymyxin B (PMB), an antibacterial cyclic lipo-peptide, is well known for its LPS sequestering and neutralizing activities. Here, we have used saturation transfer difference (STD) NMR methods for characterizing interactions of PMB with LPS from E. coli 0111:B4 and P. aeruginosa. The dissociation constants of the LPS-PMB complexes were obtained from concentration dependent STD studies. Further a detailed epitope mapping of PMB has been carried out in E. coli 0111:B4 LPS micelles. Experiments including one-dimensional 1H STD, two-dimensional 1H-1H STD-TOCSY and naturalabundance 13C-1H STD-HSQC, are performed to determine the site(s) of interactions of PMB with endotoxin at atomic resolution. Our studies reveal that the hydrophobic sidechains of PMB including a part of the N-terminus lipidic tail demonstrate close contacts with LPS. In contrast, cyclic backbone structure of PMB has the lowest STD effects suggesting a rather loose association with endotoxin.
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Affiliation(s)
- Anirban Bhunia
- Biomolecular NMR and Drug Discovery Laboratory, School of Biological Sciences, Division of Structural and Computational Biology, Nanyang Technological University, Singapore 637551
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221
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Cho YS, Yim H, Yang HT, Hur J, Chun W, Kim JH, Lee BC, Seo DK, Kim D. Use of parenteral colistin for the treatment of multiresistant Gram-negative organisms in major burn patients in South Korea. Infection 2011; 40:27-33. [DOI: 10.1007/s15010-011-0192-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2011] [Accepted: 08/15/2011] [Indexed: 11/28/2022]
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Luque S, Grau S, Berenguer N, Horcajada JP, Sorlí L, Montero MM, Salas E. [Shedding light on the use of colistin: still gaps to be filled]. Enferm Infecc Microbiol Clin 2011; 29:287-96. [PMID: 21440335 DOI: 10.1016/j.eimc.2011.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 02/03/2011] [Accepted: 02/03/2011] [Indexed: 11/28/2022]
Abstract
Colistin (polymyxin E), an old antibiotic replaced by other less toxic antibiotics in the 1970s, has been increasingly used over the last decade due to multidrug-resistance in Gram-negative bacteria and lack of new antibiotics. However, there is a dearth of information on the pharmacokinetics (PK), pharmacodynamics (PD) and toxicodynamics (TD) of colistin and its non-active prodrug colistimethate sodium (CMS). Optimised dose regimens have not been established for different types of patients. Additionally, most PK data available in the literature were obtained from concentrations derived from potentially misleading microbiological assays. Therefore, it is urgent to conduct prospective studies to optimise CMS/colistin use in patients, in particular the critically ill. This review summarises recent key clinical studies evaluating the efficacy, toxicity and PK/PD of colistin/CMS.
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Affiliation(s)
- Sonia Luque
- Servicio de Farmacia, Hospital del Mar, Barcelona, España
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223
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Sun HY, Fujitani S, Quintiliani R, Yu VL. Pneumonia due to Pseudomonas aeruginosa: part II: antimicrobial resistance, pharmacodynamic concepts, and antibiotic therapy. Chest 2011; 139:1172-1185. [PMID: 21540216 DOI: 10.1378/chest.10-0167] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa carries a notably higher mortality rate than other pneumonia pathogens. Because of its multiple mechanisms of antibiotic resistance, therapy has always been challenging. This problem has been magnified in recent years with the emergence of multidrug-resistant (MDR) pathogens often unharmed by almost all classes of antimicrobials. The objective of this article is to assess optimal antimicrobial therapy based on in vitro activity, animal studies, and pharmacokinetic/pharmacodynamic (PK/PD) observations so that evidence-based recommendations can be developed to maximize favorable clinical outcomes. Mechanisms of antimicrobial resistance of P aeruginosa are reviewed. A selective literature review of laboratory studies, PK/PD concepts, and controlled clinical trials of antibiotic therapy directed at P aeruginosa pneumonia was performed. P aeruginosa possesses multiple mechanisms for inducing antibiotic resistance to antimicrobial agents. Continuous infusion of antipseudomonal β-lactam antibiotics enhances bacterial killing. Although the advantages of combination therapy remain contentious, in vitro and animal model studies plus selected meta-analyses of clinical trials support its use, especially in the era of MDR. Colistin use and the role of antibiotic aerosolization are reviewed. An evidence-based algorithmic approach based on severity of illness, Clinical Pulmonary Infection Score, and combination antibiotic therapy is presented; clinical outcomes may be improved, and the emergence of MDR pathogens should be minimized with this approach.
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Affiliation(s)
- Hsin-Yun Sun
- Department of Internal Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Shigeki Fujitani
- Department of Emergency and Critical Care Medicine, St. Marianna University, Kawasaki-City, Kanagawa, Japan
| | | | - Victor L Yu
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA.
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Clinical practice guidelines for hospital-acquired pneumonia and ventilator-associated pneumonia in adults. CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY 2011; 19:19-53. [PMID: 19145262 DOI: 10.1155/2008/593289] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 12/19/2007] [Indexed: 02/07/2023]
Abstract
Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are important causes of morbidity and mortality, with mortality rates approaching 62%. HAP and VAP are the second most common cause of nosocomial infection overall, but are the most common cause documented in the intensive care unit setting. In addition, HAP and VAP produce the highest mortality associated with nosocomial infection. As a result, evidence-based guidelines were prepared detailing the epidemiology, microbial etiology, risk factors and clinical manifestations of HAP and VAP. Furthermore, an approach based on the available data, expert opinion and current practice for the provision of care within the Canadian health care system was used to determine risk stratification schemas to enable appropriate diagnosis, antimicrobial management and nonantimicrobial management of HAP and VAP. Finally, prevention and risk-reduction strategies to reduce the risk of acquiring these infections were collated. Future initiatives to enhance more rapid diagnosis and to effect better treatment for resistant pathogens are necessary to reduce morbidity and improve survival.
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225
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Mangoni ML, Shai Y. Short native antimicrobial peptides and engineered ultrashort lipopeptides: similarities and differences in cell specificities and modes of action. Cell Mol Life Sci 2011; 68:2267-80. [PMID: 21573781 PMCID: PMC11114904 DOI: 10.1007/s00018-011-0718-2] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 04/26/2011] [Accepted: 04/26/2011] [Indexed: 12/19/2022]
Abstract
Due to the rapid emergence of resistant microbes to the currently available antibiotics, cationic antimicrobial peptides have attracted considerable interest as a possible new generation of anti-infective compounds. However, low cost development for therapeutic or industrial purposes requires, among other properties, that the peptides will be small and with simple structure. Therefore, considerable research has been devoted to optimizing peptide length combined with a simple design. This review focuses on the similarities and differences in the mode of action and target cell specificity of two families of small peptides: the naturally occurring temporins from the skin of amphibia and the engineered ultrashort lipopeptides. We will also discuss the finding that acylation of cationic peptides results in molecules with a more potent spectrum of activity and a higher resistance to proteolytic degradation. Conjugation of fatty acids to linear native peptide sequences is a powerful strategy to engineer novel successful anti-infective drugs.
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Affiliation(s)
- Maria Luisa Mangoni
- Istituto Pasteur-Fondazione Cenci Bolognetti, La Sapienza University of Rome, 00185, Rome, Italy,
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226
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Analysis of the networks controlling the antimicrobial-peptide-dependent induction of Klebsiella pneumoniae virulence factors. Infect Immun 2011; 79:3718-32. [PMID: 21708987 DOI: 10.1128/iai.05226-11] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Antimicrobial peptides (APs) impose a threat to the survival of pathogens, and it is reasonable to postulate that bacteria have developed strategies to counteract them. Polymyxins are becoming the last resort to treat infections caused by multidrug-resistant Gram-negative bacteria and, similar to APs, they interact with the anionic lipopolysaccharide. Given that polymyxins and APs share the initial target, it is possible that bacterial defense mechanisms against polymyxins will be also effective against host APs. We sought to determine whether exposure to polymyxin will increase Klebsiella pneumoniae resistance to host APs. Indeed, exposure of K. pneumoniae to polymyxin induces cross-resistance not only to polymyxin itself but also to APs present in the airways. Polymyxin treatment upregulates the expression of the capsule polysaccharide operon and the loci required to modify the lipid A with aminoarabinose and palmitate with a concomitant increase in capsule and lipid A species containing such modifications. Moreover, these surface changes contribute to APs resistance and also to polymyxin-induced cross-resistance to APs. Bacterial loads of lipid A mutants in trachea and lungs of intranasally infected mice were lower than those of wild-type strain. PhoPQ, PmrAB, and the Rcs system govern polymyxin-induced transcriptional changes, and there is a cross talk between PhoPQ and the Rcs system. Our findings support the notion that Klebsiella activates a defense program against APs that is controlled by three signaling systems. Therapeutic strategies directed to prevent the activation of this program could be a new approach worth exploring to facilitate the clearance of the pathogen from the airways.
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227
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Abstract
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.
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228
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Carrillo-Carrión C, Simonet BM, Valcárcel M. Colistin-functionalised CdSe/ZnS quantum dots as fluorescent probe for the rapid detection of Escherichia coli. Biosens Bioelectron 2011; 26:4368-74. [PMID: 21605965 DOI: 10.1016/j.bios.2011.04.050] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 04/12/2011] [Accepted: 04/24/2011] [Indexed: 01/20/2023]
Abstract
Intensely fluorescent, colistin-functionalised CdSe/ZnS QDs (Colis-QDs) nanoparticles, are synthesized and used as sensitive probes for the detection of Escherichia coli, a Gram-negative bacteria. Colistin molecules are attached to the terminal carboxyl of the mercaptoacetic acid-capped QDs in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) as amide bond promoters. The TEM analysis of bacteria treated with Colis-QDs conjugates showed the accumulation of Colis-QDs in the cell wall of E. coli. Under the recommended working conditions, the method provides a detection limit as few as 28 E. coli cells per mL, which is competitive which more elaborate detection systems. The simplicity of the method together with short analysis time (< 15 min, without including preparation and photoactivation of the Colis-QDs conjugate) make the proposed approach useful as quick bacteria screening system.
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229
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Kwa ALH, Abdelraouf K, Low JGH, Tam VH. Pharmacokinetics of polymyxin B in a patient with renal insufficiency: a case report. Clin Infect Dis 2011; 52:1280-1. [PMID: 21507928 PMCID: PMC3115279 DOI: 10.1093/cid/cir137] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Kamilia Abdelraouf
- Department of Clinical Sciences and Administration, University of Houston College of Pharmacy, Houston, Texas
| | - Jenny G. H. Low
- Department of Infectious Diseases, Singapore General Hospital, Singapore; and
| | - Vincent H. Tam
- Department of Clinical Sciences and Administration, University of Houston College of Pharmacy, Houston, Texas
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230
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Cirioni O, Wu G, Li L, Orlando F, Silvestri C, Ghiselli R, Shen Z, Gabrielli E, Brescini L, Lezoche G, Provinciali M, Guerrieri M, Giacometti A. S-thanatin in vitro prevents colistin resistance and improves its efficacy in an animal model of Pseudomonas aeruginosa sepsis. Peptides 2011; 32:697-701. [PMID: 21262298 DOI: 10.1016/j.peptides.2011.01.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 12/30/2010] [Accepted: 01/02/2011] [Indexed: 12/20/2022]
Abstract
An experimental study was performed to evaluate the interaction between s-thanatin and colistin both in vitro and in vivo, using two Pseudomonas aeruginosa strains with different patterns of susceptibilities. We evaluated whether selecting for colistin-resistant P. aeruginosa could be prevented in vitro by combining colistin with s-thanatin. The strains were serially exposed in broth to twofold stepwise increasing concentrations of colistin alone or in combination with a fixed concentration [0.25× minimum inhibitory concentration (MIC)] of s-thanatin. We also performed an in vitro synergy study. For in vivo studies, a mouse model of Pseudomonas sepsis has been used. Main outcome measures were lethality and quantitative blood cultures. Exposure to colistin alone gradually selected for Pseudomonas strains with an increased MIC. In vitro studies, s-thanatin showed a positive interaction with colistin, and was able to prevent its resistance. In vivo studies, s-thanatin combined with colistin exhibited the highest efficacy on all main outcome measurements. These results highlight the potential usefulness of this combination and provide a future therapeutic alternative in severe Pseudomonas infections.
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Affiliation(s)
- Oscar Cirioni
- Clinic of Infectious Diseases, Department of Biomedical Sciences, Università Politecnica delle Marche, Ancona, Italy.
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Broad-spectrum antibiotic activity of the arylomycin natural products is masked by natural target mutations. ACTA ACUST UNITED AC 2011; 17:1223-31. [PMID: 21095572 DOI: 10.1016/j.chembiol.2010.09.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 09/09/2010] [Accepted: 09/13/2010] [Indexed: 11/23/2022]
Abstract
Novel classes of broad-spectrum antibiotics are needed to treat multidrug-resistant pathogens. The arylomycin class of natural products inhibits a promising antimicrobial target, type I signal peptidase (SPase), but upon initial characterization appeared to lack whole-cell activity against most pathogens. Here, we show that Staphylococcus epidermidis, which is sensitive to the arylomycins, evolves resistance via mutations in SPase and that analogous mutations are responsible for the natural resistance of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. We identify diverse bacteria lacking these mutations and demonstrate that most are sensitive to the arylomycins. The results illustrate that the arylomycins have a broad-spectrum of activity and are viable candidates for development into therapeutics. The results also raise the possibility that naturally occurring resistance may have masked other natural product scaffolds that might be developed into therapeutics.
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233
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Valera MC, da Rosa JA, Maekawa LE, de Oliveira LD, Carvalho CAT, Koga-Ito CY, Jorge AOC. Action of propolis and medications against Escherichia coli and endotoxin in root canals. ACTA ACUST UNITED AC 2011; 110:e70-4. [PMID: 20868987 DOI: 10.1016/j.tripleo.2010.01.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 01/25/2010] [Accepted: 01/29/2010] [Indexed: 11/18/2022]
Abstract
This study evaluated the action of propolis and intracanal medications against Escherichia coli and endotoxin. Forty-eight dental roots were contaminated with E. coli. The root canals were instrumented with propolis and divided into groups according to the type of intracanal medication: Ca(OH)(2), polymyxin B, or Ca(OH)(2) + 2% chlorhexidine gel. In the control group, saline solution was used without application of intracanal medication. Counts of colony-forming units were carried out and the endotoxin was quantified by the chromogenic Limulus amobocyte lysate assay. The results were evaluated by analysis of variance and the Dunn test (5%). Root canal irrigation with propolis was effective to completely eliminate E. coli and reduce the amount of endotoxins. All intracanal medications contributed to the significant decrease in endotoxins. Only intracanal medications may reduce the amount of endotoxins in the root canals. The greatest efficacy was observed for medications containing Ca(OH)(2).
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Affiliation(s)
- Marcia Carneiro Valera
- Department of Restorative Dentistry, School of Dentistry of São José dos Campos, São Paulo State University, São José dos Campos, Brazil.
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Impact of p-glycoprotein inhibition and lipopolysaccharide administration on blood-brain barrier transport of colistin in mice. Antimicrob Agents Chemother 2010; 55:502-7. [PMID: 21115788 DOI: 10.1128/aac.01273-10] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The aim of this study was to investigate the factors limiting the blood-brain barrier (BBB) transport of colistin in healthy mice and to assess the impact of systemic inflammation on the transport of this antibiotic across the BBB. Colistin sulfate (40 mg/kg) was administered subcutaneously to Swiss outbred mice as single and multiple doses to determine any relationship between brain uptake and plasma concentrations of colistin. To assess the effect of P-glycoprotein (P-gp) on BBB transport, colistin sulfate (5 mg/kg) was concomitantly administered intravenously with PSC833 or GF120918 (10 mg/kg). Systemic inflammation was induced by three intraperitoneal injections of lipopolysaccharide (LPS; 3 mg/kg), and BBB transport of colistin was subsequently measured following subcutaneous administration and by an in situ brain perfusion. The brain uptake of colistin was low following single and multiple subcutaneous doses, with brain-to-plasma concentration ratios ranging between 0.021 and 0.037, and this was not significantly enhanced by coadministration of GF120918 or PSC833 (P > 0.05). LPS significantly increased the brain uptake of subcutaneously administered colistin with area under the brain concentration time curve (AUC(brain)) values of 11.7 ± 2.7 μg·h/g and 4.0 ± 0.3 μg·h/g for LPS- and saline-treated mice, respectively (mean ± standard deviation). Similarly, in situ perfusion of colistin led to higher antibiotic brain concentrations in LPS-treated animals than in saline-treated animals, with colistin brain-to-perfusate concentration ratios of 0.019 ± 0.001 and 0.014 ± 0.001, respectively. This study demonstrates that the BBB transport of colistin is negligible in healthy mice; however, brain concentrations of colistin can be significantly enhanced during systemic inflammation, as might be observed in infected patients.
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Van den Bossche L, Van Schepdael A, Chopra S, Hoogmartens J, Adams E. Identification of impurities in polymyxin B and colistin bulk sample using liquid chromatography coupled to mass spectrometry. Talanta 2010; 83:1521-9. [PMID: 21238747 DOI: 10.1016/j.talanta.2010.11.044] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 11/09/2010] [Accepted: 11/21/2010] [Indexed: 11/17/2022]
Abstract
The European Pharmacopoeia (Ph. Eur.) describes liquid chromatography-ultraviolet (LC-UV) methods using C(18) stationary phases for the analysis of polymyxin B and colistin. Several unknown impurities were detected in commercial samples of those polypeptide complexes. However, the Ph. Eur. does not specify any related substances for polymyxin B and colistin. Since both methods use non-volatile buffers, the mobile phases were incompatible with mass spectrometry (MS). For the identification of related substances in bulk samples by LC/MS, volatile mobile phase systems were developed. However, the LC/MS methods (with volatile additives) showed inferior chromatographic separation compared to the LC-UV method (with non-volatile additives). Moreover, previously identified impurities by LC/MS could not be assigned in LC-UV methods as the separation in both systems was different. In this study, known impurities were traced in the LC-UV methods and new impurities present in polymyxin B and colistin bulk samples were characterized. To achieve this, each peak from the non-volatile system was collected separately and reinjected into an LC system with a volatile mobile phase coupled to MS. This way, collected impurity peaks were rechromatographed on a reversed phase column in order to separate the analyte from the buffer salts. Using this method, out of 39 peaks, five novel related substances were characterized in a polymyxin B bulk sample. Fourteen impurities, which were already reported in the literature were traced as good as possible in the LC-UV method. In the case of colistin, a total of 36 peaks were investigated, among which four new compounds. Additionally, 30 known impurities were traced in the LC-UV method.
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236
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Jayaraman P, Sakharkar MK, Lim CS, Tang TH, Sakharkar KR. Activity and interactions of antibiotic and phytochemical combinations against Pseudomonas aeruginosa in vitro. Int J Biol Sci 2010; 6:556-68. [PMID: 20941374 PMCID: PMC2952406 DOI: 10.7150/ijbs.6.556] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2010] [Accepted: 09/16/2010] [Indexed: 11/15/2022] Open
Abstract
In this study the in vitro activities of seven antibiotics (ciprofloxacin, ceftazidime, tetracycline, trimethoprim, sulfamethoxazole, polymyxin B and piperacillin) and six phytochemicals (protocatechuic acid, gallic acid, ellagic acid, rutin, berberine and myricetin) against five P. aeruginosa isolates, alone and in combination are evaluated. All the phytochemicals under investigation demonstrate potential inhibitory activity against P. aeruginosa. The combinations of sulfamethoxazole plus protocatechuic acid, sulfamethoxazole plus ellagic acid, sulfamethoxazole plus gallic acid and tetracycline plus gallic acid show synergistic mode of interaction. However, the combinations of sulfamethoxazole plus myricetin shows synergism for three strains (PA01, DB5218 and DR3062). The synergistic combinations are further evaluated for their bactericidal activity against P. aeruginosa ATCC strain using time-kill method. Sub-inhibitory dose responses of antibiotics and phytochemicals individually and in combination are presented along with their interaction network to suggest on the mechanism of action and potential targets for the phytochemicals under investigation. The identified synergistic combinations can be of potent therapeutic value against P. aeruginosa infections. These findings have potential implications in delaying the development of resistance as the antibacterial effect is achieved with lower concentrations of both drugs (antibiotics and phytochemicals).
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Affiliation(s)
- Premkumar Jayaraman
- Biomedical Engineering Research Centre, Nanyang Technological University, Singapore
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237
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Colistin resistance in Acinetobacter baumannii is mediated by complete loss of lipopolysaccharide production. Antimicrob Agents Chemother 2010; 54:4971-7. [PMID: 20855724 DOI: 10.1128/aac.00834-10] [Citation(s) in RCA: 570] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Infections caused by multidrug-resistant (MDR) Gram-negative bacteria represent a major global health problem. Polymyxin antibiotics such as colistin have resurfaced as effective last-resort antimicrobials for use against MDR Gram-negative pathogens, including Acinetobacter baumannii. Here we show that A. baumannii can rapidly develop resistance to polymyxin antibiotics by complete loss of the initial binding target, the lipid A component of lipopolysaccharide (LPS), which has long been considered to be essential for the viability of Gram-negative bacteria. We characterized 13 independent colistin-resistant derivatives of A. baumannii type strain ATCC 19606 and showed that all contained mutations within one of the first three genes of the lipid A biosynthesis pathway: lpxA, lpxC, and lpxD. All of these mutations resulted in the complete loss of LPS production. Furthermore, we showed that loss of LPS occurs in a colistin-resistant clinical isolate of A. baumannii. This is the first report of a spontaneously occurring, lipopolysaccharide-deficient, Gram-negative bacterium.
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238
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Michalopoulos AS, Karatza DC. Multidrug-resistant Gram-negative infections: the use of colistin. Expert Rev Anti Infect Ther 2010; 8:1009-1017. [DOI: 10.1586/eri.10.88] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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239
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Chemical Probes of Escherichia coli Uncovered through Chemical-Chemical Interaction Profiling with Compounds of Known Biological Activity. ACTA ACUST UNITED AC 2010; 17:852-62. [DOI: 10.1016/j.chembiol.2010.06.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 05/25/2010] [Accepted: 06/04/2010] [Indexed: 01/25/2023]
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240
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Colistin dosing and nephrotoxicity in a large community teaching hospital. Antimicrob Agents Chemother 2010; 54:4503-5. [PMID: 20660694 DOI: 10.1128/aac.01707-09] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thirty adult patients who received intravenous colistin (5.1 ± 2.4 mg/kg/day) were reviewed to evaluate dosing with respect to nephrotoxicity, which occurred in 10 (33%) patients within the first 5 days of treatment. Excessive colistin dosing was frequent (47%), often (71%) resulted from the use of actual body weight in obese patients, and was associated with higher rates of nephrotoxicity (80% versus 30%, P = 0.019).
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241
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Gupta S, Govil D, Kakar PN, Prakash O, Arora D, Das S, Govil P, Malhotra A. Colistin and polymyxin B: a re-emergence. Indian J Crit Care Med 2010; 13:49-53. [PMID: 19881183 PMCID: PMC2772240 DOI: 10.4103/0972-5229.56048] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
One of the greatest achievements of modern medicine is the development of antibiotics against life-threatening infections, but the emergence of multidrug-resistant (MDR) gram negative bacteria has drastically narrowed down the therapeutic options against them. This limitation has led clinicians to reappraise the clinical application of polymyxins, an old class of cationic, cyclic polypeptide antibiotics. Polymyxins are active against selected gram-negative bacteria, including the Acinetobacter species, Pseudomonas aeruginosa, Klebsiella species, and Enterobacter species. In this article, we summarise the chemistry, pharmacokinetics, and pharmacodynamics of polymyxins and the latest understanding of their action against MDR pathogens.
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Affiliation(s)
- Sachin Gupta
- Department of Anaesthesiology, Max Super Speciality Hospital, 1 Press Enclave Road, Saket, New Delhi, India.
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242
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Ramasubban S, Majumdar A, Das PS. Safety and efficacy of polymyxin B in multidrug resistant Gram-negative severe sepsis and septic shock. Indian J Crit Care Med 2010; 12:153-7. [PMID: 19742270 PMCID: PMC2738329 DOI: 10.4103/0972-5229.45074] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND AND AIMS The emergence of multidrug resistant strains of Gram-negative bacteria, especially the lactose nonfermenters like Pseudomonas and Acinetobacter, in the intensive care units have prompted renewed worldwide interest in the polymyxins. However, perceived nephrotoxicity has been a major vexation limiting their early and regular use in severe sepsis. This study was conducted to assess the safety and efficacy of polymyxin B in patients with severe sepsis and septic shock. MATERIALS AND METHODS Forty-five patients with sepsis admitted in our medical-surgical intensive care units were identified from pharmacy records to have received polymyxin B. We retrospectively reviewed the clinical and microbiologic outcomes as well as occurrence of renal failure temporally related to the use of intravenous polymyxin B. RESULTS polymyxin B was used in severe sepsis and septic shock with the isolated organism being resistant to other available antimicrobials or clinical deterioration despite carbapenem use. Overall mortality was 52% and among patients who received at least eight days of intravenous polymyxin B, 67% patients with initial septic shock and 62% with severe sepsis survived. The target multidrug resistant organism was cleared in 88% of subjects evaluated by repeat microbiologic testing. Acute renal failure developed in only two patients (4%). CONCLUSIONS Polymyxin B has acceptable effectiveness against nosocomial multidrug resistant Gram-negative sepsis. The associated nephrotoxicity has been found to be significantly lower than previously reported even in patients with background renal impairment and established risk factors of renal failure.
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Affiliation(s)
- Suresh Ramasubban
- Department of Critical Care Medicine, Apollo Gleneagles Hospital, Kolkata, W. Bengal, India.
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243
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Celebi S, Hacimustafaoglu M, Koksal N, Ozkan H, Cetinkaya M. Colistimethate sodium therapy for multidrug-resistant isolates in pediatric patients. Pediatr Int 2010; 52:410-4. [PMID: 20003141 DOI: 10.1111/j.1442-200x.2009.03015.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM The aim of the present study was to assess the efficacy and safety of colistimethate sodium therapy in multidrug-resistant 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 x 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.
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Affiliation(s)
- Solmaz Celebi
- Uludag University Medical Faculty, Department of Pediatrics, Division of Pediatric Infectious Diseases, Gorukle, Bursa, Turkey.
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244
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Nebulized and intravenous colistin in experimental pneumonia caused by Pseudomonas aeruginosa. Intensive Care Med 2010; 36:1147-55. [PMID: 20397007 DOI: 10.1007/s00134-010-1879-4] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Accepted: 02/16/2010] [Indexed: 10/19/2022]
Abstract
PURPOSE Emergence of multidrug-resistant strains in intensive care units has renewed interest in colistin, which often remains the only available antimicrobial agent active against resistant Pseudomonas aeruginosa. The aim of this study is to compare lung tissue deposition and antibacterial efficiency between nebulized and intravenous administration of colistin in piglets with pneumonia caused by P. aeruginosa. METHODS In ventilated piglets, colistimethate was administered 24 h following bronchial inoculation of Pseudomonas aeruginosa (minimum inhibitory concentration of colistin = 2 microg ml(-1)) either by nebulization (8 mg kg(-1) every 12 h, n = 6) or by intravenous infusion (3.2 mg kg(-1) every 8 h, n = 6). All piglets were killed 49 h after inoculation. Colistin peak lung tissue concentrations and lung bacterial burden were assessed on multiple post mortem subpleural lung specimens. RESULTS Median colistin peak lung concentration following nebulization was 2.8 microg g(-1) (25-75% interquartile range = 0.8-13.7 microg g(-1)). Colistin was undetected in lung tissue following intravenous infusion. In the aerosol group, peak lung tissue concentrations were significantly greater in lung segments with mild pneumonia (median = 10.0 microg g(-1), 25-75% interquartile range = 1.8-16.1 microg g(-1)) than in lung segments with severe pneumonia (median = 1.2 microg g(-1), 25-75% interquartile range = 0.5-3.3 microg g(-1)) (p < 0.01). After 24 h of treatment, 67% of pulmonary segments had bacterial counts <10(2) cfu g(-1) following nebulization and 28% following intravenous administration (p < 0.001). In control animals, 12% of lung segments had bacterial counts <10(2) cfu g(-1) 49 h following bronchial inoculation. CONCLUSION Nebulized colistin provides rapid and efficient bacterial killing in ventilated piglets with inoculation pneumonia caused by Pseudomonas aeruginosa.
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Stichtenoth G, Linderholm B, Björkman MH, Walter G, Curstedt T, Herting E. Prophylactic intratracheal polymyxin B/surfactant prevents bacterial growth in neonatal Escherichia coli pneumonia of rabbits. Pediatr Res 2010; 67:369-74. [PMID: 20035246 DOI: 10.1203/pdr.0b013e3181d026f6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In neonatal pneumonia, the surface activity of pulmonary surfactant is impaired and microorganisms may invade by passing the air-liquid interface. Previously, we have shown that addition of the antimicrobial peptide polymyxin B (PxB) to modified porcine surfactant (pSF) improves resistance to surfactant inactivation in vitro while antimicrobial activity of PxB is maintained. In this study, we investigated pSF/PxB in vivo. Neonatal near-term rabbits were treated with intratracheal pSF and/or PxB. Rabbits treated with only saline served as controls. Animals were ventilated with standardized tidal volumes and received ∼10(7) Escherichia coli intratracheally. Plethysmographic pressure-volume curves were recorded every 30 min. After 240 min, animals were killed, the right lung and left kidney were excised, and bacterial growth was determined. The left lung was used for histologic analysis. Intratracheal administration of PxB ± pSF significantly reduced the growth of E. coli compared with control animals or animals receiving only pSF. This was accompanied by reduction of severe inflammatory tissue destruction and significantly reduced bacterial translocation to the left kidney. Animals receiving pSF + PxB had no difference in lung compliance compared with the pSF- or PxB-treated group. Mixtures of PxB and pulmonary surfactant show antimicrobial effects in neonatal rabbits and prevent systemic spreading of E. coli.
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Affiliation(s)
- Guido Stichtenoth
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Solna, Sweden.
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Velkov T, Thompson PE, Nation RL, Li J. Structure--activity relationships of polymyxin antibiotics. J Med Chem 2010; 53:1898-916. [PMID: 19874036 DOI: 10.1021/jm900999h] [Citation(s) in RCA: 521] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Tony Velkov
- School of Medicine, Deakin University, Pigdons Road, Geelong 3217, Victoria, Australia.
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Guyonnet J, Manco B, Baduel L, Kaltsatos V, Aliabadi M, Lees P. Determination of a dosage regimen of colistin by pharmacokinetic/pharmacodynamic integration and modeling for treatment of G.I.T. disease in pigs. Res Vet Sci 2010; 88:307-14. [DOI: 10.1016/j.rvsc.2009.09.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 07/11/2009] [Accepted: 09/04/2009] [Indexed: 11/29/2022]
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248
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Ferjani A, Marzouk M, Ben Moussa F, Boukadida J. Résistance des souches d’Escherichia coli isolées de prélèvements d’origine urinaire vis-à-vis de l’association amoxicilline–acide clavulanique et divers antibiotiques. Med Mal Infect 2010; 40:161-4. [DOI: 10.1016/j.medmal.2009.06.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 06/04/2009] [Indexed: 10/20/2022]
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Dörr T, Vulić M, Lewis K. Ciprofloxacin causes persister formation by inducing the TisB toxin in Escherichia coli. PLoS Biol 2010; 8:e1000317. [PMID: 20186264 PMCID: PMC2826370 DOI: 10.1371/journal.pbio.1000317] [Citation(s) in RCA: 534] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 01/20/2010] [Indexed: 11/18/2022] Open
Abstract
Bacteria induce stress responses that protect the cell from lethal factors such as DNA-damaging agents. Bacterial populations also form persisters, dormant cells that are highly tolerant to antibiotics and play an important role in recalcitrance of biofilm infections. Stress response and dormancy appear to represent alternative strategies of cell survival. The mechanism of persister formation is unknown, but isolated persisters show increased levels of toxin/antitoxin (TA) transcripts. We have found previously that one or more components of the SOS response induce persister formation after exposure to a DNA-damaging antibiotic. The SOS response induces several TA genes in Escherichia coli. Here, we show that a knockout of a particular SOS-TA locus, tisAB/istR, had a sharply decreased level of persisters tolerant to ciprofloxacin, an antibiotic that causes DNA damage. Step-wise administration of ciprofloxacin induced persister formation in a tisAB-dependent manner, and cells producing TisB toxin were tolerant to multiple antibiotics. TisB is a membrane peptide that was shown to decrease proton motive force and ATP levels, consistent with its role in forming dormant cells. These results suggest that a DNA damage-induced toxin controls production of multidrug tolerant cells and thus provide a model of persister formation.
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Affiliation(s)
- Tobias Dörr
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Marin Vulić
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Kim Lewis
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
- * E-mail:
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Current use for old antibacterial agents: polymyxins, rifamycins, and aminoglycosides. Infect Dis Clin North Am 2010; 23:1053-75, x. [PMID: 19909897 DOI: 10.1016/j.idc.2009.06.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This article reviews three classes of antibacterial agents that are uncommonly used in bacterial infections and therefore can be thought of as special-use agents. The polymyxins are reserved for gram-negative bacilli that are resistant to virtually all other classes of drugs. Rifampin is used therapeutically, occasionally as a companion drug in treatment of refractory gram-positive coccal infections, especially those involving foreign bodies. Rifaximin is a new rifamycin that is a strict enteric antibiotic approved for treatment of traveler's diarrhea and is showing promise as a possible agent for refractory Clostridium difficile infections. The aminoglycosides are used mainly as companion drugs for the treatment of resistant gram-negative bacillary infections and for gram-positive coccal endocarditis.
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