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Plastic binding feature of polymyxins: the effect on MIC susceptibility measurements
Toktam Sharafi1,2, Abdollah Ardebili1,2
1Infectious Disease Research Center, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran.
Abstract:
The loss of polycationic antimicrobial peptides, polymyxins, due to adhesion to plastics is an important subject matter that influences in vitro susceptibility testing, including minimum inhibitory concentration (MIC) assays. This review reminds us that this issue can serve as a significant source of variation in the MIC values for polymyxins against Gram-negative bacteria.
Insights
Polymyxin antimicrobial peptides bind to plastics, affecting in vitro testing. This adhesion causes significant variation in minimum inhibitory concentration (MIC) results for Gram-negative bacteria.
Area of Science:
- Microbiology
- Pharmacology
- Biochemistry
Background:
- Polymyxins are critical polycationic antimicrobial peptides used against Gram-negative bacterial infections.
- Adsorption of polymyxins to plastic surfaces is a known phenomenon impacting experimental outcomes.
- Accurate in vitro susceptibility testing is crucial for effective antibiotic therapy.
Purpose of the Study:
- To highlight the impact of polymyxin adhesion to plastics on in vitro susceptibility testing.
- To underscore the variability introduced in minimum inhibitory concentration (MIC) assays due to this phenomenon.
- To inform researchers and clinicians about a critical factor influencing polymyxin efficacy data.
Main Methods:
- This is a review article, synthesizing existing research on polymyxin-plastic interactions.
- The focus is on analyzing the consequences of peptide adsorption in the context of MIC determination.
- Literature was reviewed to identify studies demonstrating polymyxin loss and its effect on bacterial susceptibility.
Main Results:
- Polymyxin adhesion to plastic materials leads to a significant loss of active drug.
- This loss directly contributes to variability and potential inaccuracies in reported MIC values.
- The extent of variation can be substantial, potentially leading to misinterpretation of bacterial susceptibility.
Conclusions:
- The adsorption of polymyxins to plastics is a critical confounding factor in in vitro susceptibility testing.
- Researchers must consider and mitigate this issue to obtain reliable MIC data for polymyxins.
- Addressing polymyxin loss is essential for accurate assessment of treatment efficacy against Gram-negative bacteria.
