Comparison of the binding of gram-negative bacterial endotoxin by polymyxin B sulphate, colistin sulphate and colistin sulphomethate sodium

Infection ◽  
1986 ◽  
Vol 14 (2) ◽  
pp. 79-81 ◽  
Author(s):  
M. J. Rogers ◽  
J. Cohen
Keyword(s):  
Polymyxin B ◽  
Bacterial Endotoxin ◽  
Gram Negative

scholarly journals The Lipid Lysyl-Phosphatidylglycerol Is Present in Membranes of Rhizobium tropici CIAT899 and Confers Increased Resistance to Polymyxin B Under Acidic Growth Conditions

2007 ◽  
Vol 20 (11) ◽  
pp. 1421-1430 ◽  
Author(s):  
Christian Sohlenkamp ◽  
Kanaan A. Galindo-Lagunas ◽  
Ziqiang Guan ◽  
Pablo Vinuesa ◽  
Sally Robinson ◽  
...  
Keyword(s):  
Sinorhizobium Meliloti ◽  
Minimal Medium ◽  
Polymyxin B ◽  
Growth Conditions ◽  
Membrane Lipid ◽  
Low Ph ◽  
Wild Type ◽  
Rhizobium Tropici ◽  
Gram Negative ◽  
Inducible Genes

Lysyl-phosphatidylglycerol (LPG) is a well-known membrane lipid in several gram-positive bacteria but is almost unheard of in gram-negative bacteria. In Staphylococcus aureus, the gene product of mprF is responsible for LPG formation. Low pH-inducible genes, termed lpiA, have been identified in the gram-negative α-proteobacteria Rhizobium tropici and Sinorhizobium medicae in screens for acid-sensitive mutants and they encode homologs of MprF. An analysis of the sequenced bacterial genomes reveals that genes coding for homologs of MprF from S. aureus are present in several classes of organisms throughout the bacterial kingdom. In this study, we show that the expression of lpiA from R. tropici in the heterologous hosts Escherichia coli and Sinorhizobium meliloti causes formation of LPG. A wild-type strain of R. tropici forms LPG (about 1% of the total lipids) when the cells are grown in minimal medium at pH 4.5 but not when grown in minimal medium at neutral pH or in complex tryptone yeast (TY) medium at either pH. LPG biosynthesis does not occur when lpiA is deleted and is restored upon complementation of lpiA-deficient mutants with a functional copy of the lpiA gene. When grown in the low-pH medium, lpiA-deficient rhizobial mutants are over four times more susceptible to the cationic peptide polymyxin B than the wild type.

scholarly journals Prevalence of multidrug-resistant and extended-spectrum beta-lactamase producing Gram-negative isolates from clinical samples in a tertiary care hospital of Nepal

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Aryatara Shilpakar ◽  
Mehraj Ansari ◽  
Kul Raj Rai ◽  
Ganesh Rai ◽  
Shiba Kumar Rai
Keyword(s):  
Tertiary Care Hospital ◽  
Tertiary Care ◽  
Polymyxin B ◽  
Multidrug Resistant ◽  
Confirmatory Test ◽  
Clinical Samples ◽  
Care Hospital ◽  
Gram Negative ◽  
Extended Spectrum ◽  
Esbl Producers

Abstract Background The existence of multidrug-resistant organisms, including extended-spectrum beta-lactamases (ESBLs), is on rise across the globe and is becoming a severe problem. Knowledge of the prevalence and antibiogram profile of such isolates is essential to develop an appropriate treatment methodology. This study aimed to study the prevalence of Gram-negative isolates exhibiting ESBL at a tertiary care hospital and study their antibiogram profile. Methods A cross-sectional study was conducted at Shahid Gangalal National Heart Centre, Kathmandu, Nepal, from June 2018 to November 2018. A total of 770 clinical samples were collected and identified using the conventional biochemical tests following the Clinical and Laboratory Standard Institute (CLSI) guidelines. Antimicrobial susceptibility testing (AST) was performed using the standardized Kirby-Bauer disk diffusion method. The screening test for ESBL producers was performed as recommended by the CLSI and the confirmatory test was performed phenotypically using the E-test. Results Out of the 92 isolates, 84 (91.3%) were multidrug-resistant, and 47 (51.1%) were found to be potential ESBL producers. Of these, 16 isolates were confirmed ESBL producers by the E-test. Escherichia coli and Klebsiella pneumoniae were the predominant isolates and were also the major ESBL producers. Besides polymyxin B (100% sensitive), meropenem and imipenem showed high efficacy against the ESBL producers. Conclusion Multidrug resistance was very high; however, ESBL production was low. Polymyxin B and carbapenems are the choice of drugs against ESBL producers but should be used only as the last line drugs.

scholarly journals Some Effects of Gram-negative Bacterial Endotoxin and its Importance as a Contaminator of Biological Preparations

1989 ◽  
Vol 31 (2) ◽  
pp. 193-206 ◽  
Author(s):  
Chahna R. Yagoda ◽  
Ann-Christin Bylund-Fellenius ◽  
Hans Kindahl
Keyword(s):  
Bacterial Endotoxin ◽  
Gram Negative

scholarly journals Polymyxin B Nephrotoxicity and Efficacy against Nosocomial Infections Caused by Multiresistant Gram-Negative Bacteria

2003 ◽  
Vol 47 (8) ◽  
pp. 2659-2662 ◽  
Author(s):  
John P. Ouderkirk ◽  
Jill A. Nord ◽  
Glenn S. Turett ◽  
Jay Ward Kislak
Keyword(s):  
Renal Failure ◽  
Renal Function ◽  
Renal Toxicity ◽  
Clinical Information ◽  
Polymyxin B ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Length Of Treatment ◽  
Baseline Renal Function ◽  
Overall Mortality

ABSTRACT Reported rates of nephrotoxicity associated with the systemic use of polymyxins have varied widely. The emergence of infections due to multiresistant gram-negative bacteria has necessitated the use of systemic polymyxin B once again for the treatment of such infections. We retrospectively investigated the rate of nephrotoxicity in patients receiving polymyxin B parenterally for the treatment of infections caused by multiresistant gram-negative bacteria from October 1999 to September 2000. Demographic and clinical information was obtained for 60 patients. Outcome measures of interest were renal toxicity and clinical and microbiologic efficacy. Renal failure developed in 14% of the patients, all of whom had normal baseline renal function. Development of renal failure was independent of the daily and cumulative doses of polymyxin B and the length of treatment but was significantly associated with older age (76 versus 59 years, P = 0.02). The overall mortality was 20%, but it increased to 57% in those who developed renal failure. The organism was cleared in 88% of the patients from whom repeat specimens were obtained. The use of polymyxin B to treat multiresistant gram-negative infections was highly effective and associated with a lower rate of nephrotoxicity than previously described.

scholarly journals TO STUDY ANTIBIOTIC SENSITIVITY PATTERN OF NONFERMENTATIVE GRAM NEGATIVE BACILLI FROM VARIOUS CLINICAL SAMPLES IN A TERTIARY CARE HOSPITAL, JAIPUR.

2020 ◽  
Vol 4 (5) ◽  
Author(s):  
Kirti Hemwani ◽  
P. S. Nirwan ◽  
Preeti Shrivastava ◽  
Abhiraj Ramchandani
Keyword(s):  
Tertiary Care ◽  
Antibiotic Sensitivity ◽  
Polymyxin B ◽  
Hospital Environment ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Care Hospital ◽  
Pathogenic Potential ◽  
Gram Negative ◽  
Sensitivity Pattern

Background: Nonfermentative gram negative bacilli (NFGNB) frequently considered as commensals or contaminants but the pathogenic potential of nonfermenters has been proved beyond doubt. They are resistant to commonly used antimicrobials. Aim: This study was undertaken to identify the nonfermenters isolated from various clinical samples and to know their Antibiotic sensitivity pattern. Materials and Methods: The present study was carried out on 150 strains of Nonfermenters isolated from 1200 various non repetitive clinical samples received in Department of Microbiology, NIMS Jaipur. Nonfermenters were identified using a standard protocol and their antibiotic susceptibility testing was performed with the help of the modified Bauer disc diffusion method. Results: Out of 150 nonfermenters isolated, Pseudomonas aeruginosa was the most common isolate 134 (89.33%) followed by Acinetobacter baumannii 16 (10.67%). Among all clinical samples Pus and Wound Discharge yield maximum isolates of NFGNB i.e. 54 (36%) % followed by sputum (39.0%). Most sensitive drug against NFGNB was Polymyxin-B (100%) followed by Imipenem (86 %) and Amikacin (71.33 %). Conclusion: Nonfermenters have a great potential to survive in a hospital environment so implementation of antibiotic stewardship programs and strict infection control practices will be required to prevent or slow down their emergence and spread. Keywords:  Nonfermenters,  Polymyxin-B, Pseudomonas, Acinetobacter.

scholarly journals Polymyxins Nebulization over Intravenous Injection: Pharmacokinetics and Pharmacodynamics-Based Therapeutic Evaluation

2019 ◽  
pp. 1-10
Author(s):  
Md. Jahidul Hasan
Keyword(s):  
Respiratory Tract ◽  
Adverse Drug Reactions ◽  
Intravenous Administration ◽  
Polymyxin B ◽  
Multidrug Resistant ◽  
Drug Reactions ◽  
Pharmacokinetics And Pharmacodynamics ◽  
Gram Negative ◽  
Tract Infections

Polymyxins are the last line potential antibiotics against multi-drug resistant gram-negative bacteria and consist of two sister antibiotics: Polymyxin B and colistin (polymyxin E). Intravenous use of polymyxins was started from a long ago in the treatment of serious gram-negative infections and once their uses were restricted due to potential adverse drug reactions, such as nephrotoxicity and neurotoxicity. Lack of in vivo clinical studies on polymyxins mostly, in human body makes the pharmacokinetics and pharmacodynamics of polymyxin B and colistin unclear in many aspects, such as the distribution of polymyxins in different compartments of lung. The nebulization of polymyxins is practicing very limitedly and lack of clinical evidence has not justified this administration technique yet properly to date. The main objective of this review study was to evaluate the pharmacokinetic and pharmacodynamic properties of intravenous and nebulized polymyxins and the related therapeutic potentialities. Aerosolized polymyxins directly administered to the respiratory tract was found with higher drug concentration in different subcompartments of lungs than the intravenous administration and sustainably meets the minimum inhibitory concentration locally with superior bactericidal properties in respiratory tract infections. In contrast, intravenous administration of polymyxins shows similar anti-infective superiority in other organs, such as blood, urinary tract etc. So, during this alarming situation of rapidly emerging multidrug-resistant organisms in human communities, therapeutic administration techniques of last resort polymyxins should be clinically evidence-based for achieving optimum therapeutic outcomes with minimum chance of adverse drug reactions.  

scholarly journals Visualizing the Potential Impairment of Polymyxin B to Central Nervous System Through MR Susceptibility-Weighted Imaging

2021 ◽  
Vol 12 ◽  
Author(s):  
Ni Zhang ◽  
Lichong Zhu ◽  
Qiuhong Ouyang ◽  
Saisai Yue ◽  
Yichun Huang ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Polymyxin B ◽  
Susceptibility Weighted Imaging ◽  
Gram Negative Bacteria ◽  
Severe Toxicity ◽  
Gram Negative ◽  
The Impact

Polymyxin B (PMB) exert bactericidal effects on the cell wall of Gram-negative bacteria, leading to changes in the permeability of the cytoplasmic membrane and resulting in cell death, which is sensitive to the multi-resistant Gram-negative bacteria. However, the severe toxicity and adverse side effects largely hamper the clinical application of PMB. Although the molecular pathology of PMB neurotoxicity has been adequately studied at the cellular and molecular level. However, the impact of PMB on the physiological states of central nervous system in vivo may be quite different from that in vitro, which need to be further studied. Therefore, in the current study, the biocompatible ultra-uniform Fe3O4 nanoparticles were employed for noninvasively in vivo visualizing the potential impairment of PMB to the central nervous system. Systematic studies clearly reveal that the prepared Fe3O4 nanoparticles can serve as an appropriate magnetic resonance contrast agent with high transverse relaxivity and outstanding biosafety, which thus enables the following in vivo susceptibility-weighted imaging (SWI) studies on the PMB-treated mice models. As a result, it is first found that the blood-brain barrier (BBB) of mice may be impaired by successive PMB administration, displaying by the discrete punctate SWI signals distributed asymmetrically across brain regions in brain parenchyma. This result may pave a noninvasive approach for in-depth studies of PMB medication strategy, monitoring the BBB changes during PMB treatment, and even assessing the risk after PMB successive medication in multidrug-resistant Gram-negative bacterial infected patients from the perspective of medical imaging.

Polymyxin B-modified conjugated oligomer nanoparticle for targeted identification and enhanced photodynamic antimicrobial therapy

2021 ◽  
Author(s):  
Qi Jiang ◽  
Xinrong Yan ◽  
Dan Jiao ◽  
Jiangyan Zhang ◽  
Yonggang Wu ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Antimicrobial Therapy ◽  
Polymyxin B ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Photodynamic Antimicrobial Therapy

We report a photosensitive polymyxin B-modified conjugated oligomer nanoparticle that integrates the targeted identification and synergistic photodynamic therapy in one treatment against resistant gram-negative bacteria. The study expands the application...

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