Related Experiment Video

Updated: Jul 15, 2026

Antimicrobial Synergy Testing by the Inkjet Printer-assisted Automated Checkerboard Array and the Manual Time-kill Method
12:03

Antimicrobial Synergy Testing by the Inkjet Printer-assisted Automated Checkerboard Array and the Manual Time-kill Method

Published on: April 18, 2019

Polymyxin antibiotics for gram-negative infections

Tamra M Arnold1, Graeme N Forrest, Karen J Messmer

  • 1Richard L. Roudebush Veterans Affairs Medical Center (VAMC), Indianapolis, IN 46202, and School of Medicine, University of Maryland, Baltimore, USA. tamra.arnold@va.gov

American Journal of Health-System Pharmacy : AJHP : Official Journal of the American Society of Health-System Pharmacists
|April 11, 2007
PubMed
Abstract

Insights

Polymyxin antibiotics are effective against multidrug-resistant gram-negative infections, offering a last resort option. Recent data suggest lower toxicity than previously reported, making them a viable treatment choice when necessary.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pharmacology

Background:

  • Antimicrobial resistance is a growing global health crisis, particularly in hospital settings.
  • Polymyxins, derived from Bacillus species, are effective against Gram-negative bacteria due to their detergent-like action.
  • Historically, polymyxins were associated with significant nephrotoxicity and neurotoxicity, limiting their use.

Purpose of the Study:

  • To review the role of polymyxin antibiotics in treating multidrug-resistant Gram-negative infections.
  • To assess the current understanding of polymyxin efficacy and toxicity.

Main Methods:

  • Literature review of clinical trials and studies on polymyxin antibiotics.
  • Analysis of historical and recent data on polymyxin usage, effectiveness, and adverse events.

Main Results:

  • Emergence of multidrug-resistant Gram-negative organisms has led to increased polymyxin use.
  • Recent studies indicate that polymyxin-associated nephrotoxicity and neurotoxicity may be less frequent and severe than previously believed.
  • Clinical trials demonstrate acceptable effectiveness of polymyxins for treating multidrug-resistant Gram-negative infections.

Conclusions:

  • Polymyxins are a crucial last-resort treatment for infections caused by multidrug-resistant Gram-negative bacteria.
  • While effective, polymyxins should not be considered first-line therapy until further research clarifies their safety profile.
  • The reevaluation of polymyxin toxicity suggests a more favorable risk-benefit ratio in specific clinical scenarios.

More Related Videos

Generating Transposon Insertion Libraries in Gram-Negative Bacteria for High-Throughput Sequencing08:19

Generating Transposon Insertion Libraries in Gram-Negative Bacteria for High-Throughput Sequencing

Published on: July 7, 2020

Related Concept Videos

Inhibitors of Gram-positive Cell Wall Synthesis01:23

Inhibitors of Gram-positive Cell Wall Synthesis

Bacterial cell walls are typically rigid structures composed mainly of peptidoglycan, a mesh-like polymer that provides mechanical strength and maintains cell shape. The synthesis of peptidoglycan is a crucial process in bacterial growth and serves as a primary target for many antibiotics.Mechanism of Action of Beta-Lactam AntibioticsBeta-lactam antibiotics, such as penicillin, inhibit peptidoglycan synthesis in actively growing cells. These antibiotics share a characteristic four-membered...
Inhibitors of Bacterial Protein Synthesis01:25

Inhibitors of Bacterial Protein Synthesis

Aminoglycosides constitute a highly potent class of bactericidal antibiotics that exert their antimicrobial effects by targeting the bacterial ribosome, specifically disrupting protein synthesis. These polycationic molecules consist of amino-modified sugars linked via glycosidic bonds to an aminocyclitol core such as 2-deoxystreptamine or streptamine. Their strong positive charges facilitate tight binding to the negatively charged phosphate backbone of ribosomal RNA (rRNA), primarily at the 16S...
Combined Effects of Drugs: Synergism01:27

Combined Effects of Drugs: Synergism

Synergism is a useful mechanism where combining two or more drugs is more effective than each constituent used alone. Such combinations are also called supra-additive interactions. The drugs collectively enhance the final therapeutic effect by acting on different targets. Another advantage is that the low dose of each constituent drug is sufficient to achieve the desired effect. This helps reduce the duration of therapy and lower the adverse effects of these drugs.
Such synergistic combinations...
Inhibitors of Bacterial DNA Synthesis01:28

Inhibitors of Bacterial DNA Synthesis

Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These antibiotics are selectively...
Production of Antibiotics01:27

Production of Antibiotics

Penicillin, one of the earliest and most widely used antibiotics, is produced industrially by the filamentous fungus Penicillium chrysogenum. Large stirred-tank bioreactors ranging from tens to hundreds of thousands of liters maintain tightly controlled temperature, pH, and dissolved oxygen conditions to support fungal metabolism and maximize antibiotic yield. Penicillin is a secondary metabolite, synthesized primarily during the stationary growth phase, which requires a carefully managed...
Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...