Isolation and partial characterization of Bac201: A plasmid-associated bacteriocin-like inhibitory substance fromStaphylococcus aureus AB201

Abstract

Staphylococcus aureus AB201, a clinical isolate from wound pus, produced a bacteriocin‐like inhibitory substance termed as Bac201 that exhibited a broad‐spectrum activity against both gram‐positive as well as gram‐negative bacteria. Among gram‐negative bacteria it was active against Neisseria meningitidis and Acinetobacter calcoaceticus both being gram‐negative cocci. Inhibition due to the effect of organic acids, hydrogen peroxide, or bacteriophages was excluded. This inhibitory substance could not be induced or eluted. It was partially purified to 80% saturation by ammonium sulfate precipitation resulting in maximum specific activity of 829 AU/mg (25‐fold increase). Proteolytic enzymes rapidly inactivated the antagonistic activity of the partially purified material, whereas glycolytic and lipolytic enzymes had no effect. It remained stable in the presence of mild organic solvents. It could be stored at —20 °C without loss of activity, stable at 60 °C and 80°C for 30 min, 100 °C for 20 min and autoclaving temperature (121 °C for 15 min), and exhibited activity within a wide range of pH (2.5—10). Bac201 had an estimated Mr of 41kDa, as indicated by activity detection after SDS‐PAGE. Temperature‐mediated (44 °C) plasmid curing studies suggested linkage of bacteriocin production to a 4.8 MDa plasmid. The Bac201 was bactericidal rather than bacteriolytic.

Production, purification and some properties of Bac201, a bacteriocin-like inhibitory substance produced byStaphylococcus aureus AB201

“…The six peaks were collected separately during GF-HPLC and activity of each peak was checked. The target organism was Staphylococcus aureus Neisseria meningitidis and Acinetobacter calcoaceticus, both being clinically significant gram-negative cocci has already been described (IQBAL et al 1999). The data also demonstrate that Staphylococcus aureus AB201, in addition to possessing Bac201 activity, has the immunity factors necessary to protect itself from its own lethal effects (Fig.…”

“…The bacteriocin activity is present in the supernatant, as it could not be eluted, should it be associated with cell membrane. The bacteriocin-like activity was not due to viruses, organic acids or hydrogen peroxide (IQBAL et al 1999). Bac201 was purified by ammonium sulfate precipitation followed by gel-filtration and reversed-phase high performance liquid chromatography.…”

“…Initial characterization of Bac201 from Staphylococcus aureus AB201 has already been reported (IQBAL et al 1999). The present communication describes its purification and characterization as a high molecular mass, extremely stable, glycine-rich, broad-spectrum, bacteriocin-like inhibitory substance.…”

“…Bac201 could conclusively be classified as heat stable, since full biological activity was retained after heating at 100 GC for 15 min (IQBAL et al 1999). However, purified Bac201 activity was rapidly inactivated at autoclaving temperature (121 GC for 15 min).…”

Production, purification and some properties of Bac201, a bacteriocin-like inhibitory substance produced by Staphylococcus aureus AB201

“…Bac201 was tested for sensitivity to pH, heat and various enzymes (Table 2). Bac201 could conclusively be classified as heat stable, since full biological activity was retained after heating at 100 GC for 15 min (IQBAL et al 1999). However, purified Bac201 activity was rapidly inactivated at autoclaving temperature (121 GC for 15 min).…”