Exploring clinically isolated Staphylococcus sp. bacteriocins revealed the production of amonabactin, micrococcin, and α-circulocin

Abstract

Background and Objectives: Bacteriocins are considered alternative non-conventional antimicrobials produced by certain bacteria with activity against closely related species. The present study focuses on screening, characterization, and partial purification of bacteriocins produced by Staphylococcus sp. isolated from different clinical sources such as pus and blood.
 Materials and Methods: A total of 100 Staphylococcus isolates were screened for bacteriocin production using spot on lawn assay and agar diffusion method against five indicator bacteria. Bacteriocins from five selected highly active isolates were subjected to proteinase-K enzyme, different pH, and heating at different temperatures, and investigated the stabilities of their antimicrobials. Two selected isolates, MK65 and MK88, were molecularly identified by 16S rRNA gene sequencing, explored for the presence of 18 bacteriocin genes, and liquid chromatography-high resolution electrospray ionization mass spectrometry (LC-HRESIMS) was used to identify their different metabolites.
 Results: Twenty isolates exhibited inhibitory effect against at least one indicator bacteria. Micrococcus luteus ATCC 4698 showed the highest sensitivity to such bacteriocins. Proteinase K, acidic pH, and heating at 100°C triggered marked activity inhibition. However, amylase enzyme, alkaline pH, and heating at 80°C caused trivial effects. Four out of eighteen bacteriocin genes were detected using PCR. Fermentation, partial purification, and LC-HRESIMS of total protein extracts of two selected isolates, MK65 and MK88, revealed the production of different antimicrobial peptides.
 Conclusion: To the best of our knowledge, this is the first study to report the production of micrococcin and α-circulocin from Staphylococcus aureus MK65 and the production of amonabactin from Staphylococcus epidermidis MK88.

Inhibition of Clinical MRSA Isolates by Coagulase Negative Staphylococci of Human Origin

“…This study screened a bank of CoNS against clinical isolates of MRSA in an at tempt to identify antimicrobial producers with activity against this specific pathogen Twenty-one MRSA isolates were used to reduce the likelihood that natural variations in antimicrobial susceptibility amongst the S. aureus strains would result in a putative anti microbial producer being overlooked. Unlike many other bacteriocin investigations which screen CoNS against a broad range of indicators or a specific sensitive indicato during the preliminary testing [36,[38][39][40], this investigation took a more directed ap proach with a single target pathogen in mind.…”

Horizontal Transfer of Bacteriocin Biosynthesis Genes Requires Metabolic Adaptation To Improve Compound Production and Cellular Fitness

“…Using our collection of nasal staphylococcal isolates, we identified the S. aureus strain D4-19 with a plasmid carrying the MP1 BGC. A number of studies have identified MP1 BGCs in a variety of staphylococcal species, including S. aureus ( 34 ), S. epidermidis ( 35 ), Staphylococcus equorum ( 36 ), Staphylococcus pseudintermedius ( 37 ), Staphylococcus agnetis , and S. hominis ( 20 ). Also, an isolate from Mammaliicoccus sciuri (formerly Staphylococcus sciuri ) ( 38 ) has been shown to produce MP1.…”

Horizontal transfer of bacteriocin biosynthesis genes requires metabolic adaptation to improve compound production and cellular fitness

“…Using our collection of nasal staphylococcal isolates, we identified the S. aureus strain D4-19 carrying a plasmid encoding the MP1 BGC. A number of studies have identified MP1-BGCs in a variety of staphylococcal species, including S. aureus (32), S. epidermidis (33), Staphylococcus equorum (34), Staphylococcus pseudintermediu s (35), Staphylococcus agnetis , and S. hominis (19). Also, an isolate from Mammaliicoccus sciuri (former Staphylococcus sciuri ) (36) has been shown to produce MP1.…”