Antibacterial effect of protamine assayed by impedimetry

Area of Science:

• Microbiology
• Biochemistry
• Analytical Chemistry

Background:

• Protamine, a basic peptide, exhibits antimicrobial properties.
• Assessing bacterial viability and susceptibility to antimicrobial agents is crucial.

Purpose of the Study:

• To evaluate the antibacterial efficacy of protamine using impedimetric measurements.
• To determine the minimum inhibitory concentrations (MIC) of protamine against various bacterial strains.
• To compare the effects of protamine on growing versus non-growing bacterial cells.

Main Methods:

• Impedimetric measurements were employed to quantify bacterial cell numbers and assess protamine's effect.
• A linear correlation between impedance detection time and initial cell counts was established for accurate cell estimation.
• Minimum inhibitory concentrations (MIC) were determined for both Gram-positive and Gram-negative bacteria.

Main Results:

• Protamine demonstrated bactericidal activity against growing Gram-positive bacteria and significant growth inhibition of Gram-negative bacteria.
• Gram-positive bacteria were generally more susceptible to protamine than Gram-negative bacteria, with lower MIC values.
• Protamine was lethal to non-growing Listeria monocytogenes and Shewanella putrefaciens under specific conditions.

Conclusions:

• Impedimetric analysis provides a reliable method for assaying the antibacterial effects of protamine.
• Protamine exhibits potent antibacterial activity, particularly against growing Gram-positive bacteria.
• The susceptibility of bacteria to protamine varies based on growth status and Gram-type.