Lividomycin resistance in staphylococci by enzymatic phosphorylation

Area of Science:

• Microbiology
• Biochemistry
• Molecular Biology

Background:

• Lividomycin (LV) is an aminoglycoside antibiotic.
• Antibiotic resistance in staphylococci is a growing concern.
• Enzymatic inactivation is a known mechanism of antibiotic resistance.

Purpose of the Study:

• To investigate the enzymatic inactivation of lividomycin (LV) by clinical isolates of staphylococci.
• To identify and characterize the enzyme responsible for LV inactivation.
• To compare the LV inactivation mechanism in staphylococci with that in Escherichia coli.

Main Methods:

• Testing nine clinical staphylococci isolates (susceptible and resistant) for LV inactivation.
• Using cell-free extracts to demonstrate enzymatic activity and (32)P incorporation into LV.
• Purifying the LV-inactivating enzyme from a resistant Staphylococcus aureus strain using ammonium sulfate fractionation and column chromatography.
• Comparing the properties of the purified enzyme and its phosphorylated product with those from Escherichia coli.

Main Results:

• LV inactivation and enzymatic phosphorylation were observed only in cell-free extracts from LV-resistant staphylococci strains.
• An LV-phosphorylating enzyme was purified approximately 82-fold from a resistant Staphylococcus aureus strain.
• The partially purified enzyme and its phosphorylated product (5''-phosphoryl-LV) showed similarities to those found in Escherichia coli with R factors conferring LV resistance.

Conclusions:

• Staphylococci can inactivate lividomycin through an enzymatic phosphorylation mechanism.
• This mechanism is mediated by an enzyme with properties similar to those found in other bacteria carrying resistance factors.
• The findings contribute to understanding aminoglycoside antibiotic resistance in staphylococci.