Draft genome sequence of Staphylococcus agnetis 4244, a strain with gene clusters encoding distinct post-translationally modified antimicrobial peptides.

OBJECTIVES: Here we report the draft genome sequence of Staphylococcus agnetis 4244, a strain involved in bovine mastitis, and its ability to inhibit different species of antibiotic-resistant Gram-positive bacteria owing to bacteriocin production. METHODS: An Illumina MiSeq platform was used for genome sequencing. De novo genome assembly was done using the A5-miseq pipeline. Genome annotation was performed by the RAST server, and mining of bacteriocinogenic gene clusters was done using the BAGEL4 and antiSMASH v.5.0 platforms. Investigation of the spectrum of activity of S. agnetis 4244 was performed on BHI agar by deferred antagonism assay. RESULTS: The total scaffold size was determined to be 2 511 708 bp featuring a G+C content of 35.6%. The genome contains 2431 protein-coding sequences and 80 RNA sequences. Genome analyses revealed three prophage sequences inserted in the genome as well as several genes involved in drug resistance and two bacteriocin gene clusters (encoding a thiopeptide and a sactipeptide) encoded on the bacterial chromosome. Staphylococcus agnetis 4244 was able to inhibit all 44 strains of antibiotic-resistant Gram-positive bacteria tested in this study, including vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA) and other antibiotic-resistant staphylococcal strains. CONCLUSION: This study emphasises the potential biotechnological application of this strain for production of bacteriocins that could be used in the food industry as biopreservatives and/or in medicine as alternative therapeutic options against VRE, MRSA, vancomycin-intermediate S. aureus and other antibiotic-resistant Gram-positive bacteria, including biofilm-forming isolates. It also provides some genetic features of the draft genome of S. agnetis 4244.

Hyicin 4244, the first sactibiotic described in staphylococci, exhibits an anti-staphylococcal biofilm activity.

Hyicin 4244 is a small antimicrobial peptide with a broad spectrum of activity that was found in the culture supernatant of Staphylococcus hyicus 4244, the genome of which was then sequenced. The bacteriocin gene cluster (hyiSABCDEFG) was mined from its single chromosome and exhibited a genetic organization similar to that of subtilosin A. All genes involved in hyicin 4244 biosynthesis proved to be transcribed and encode proteins that share at least 42% similarity to proteins encoded by the subtilosin A gene cluster. Due to its resemblance to subtilosin A and the presence of three thioether bonds in its structure, hyicin 4244 is assumed to be a 35-amino acid circular sactibiotic, the first to be described in staphylococci. Hyicin 4244 inhibited 14 staphylococcal isolates from either human infections or bovine mastitis, all biofilm formers. Hyicin 4244 significantly reduced the number of colony-forming units (CFU) and the biofilm formation by two strong biofilm-forming strains randomly chosen as representatives of the strains involved in human infections and bovine mastitis. It also reduced the proliferation and viability of sessile cells in established biofilms. Therefore, hyicin 4244 proved not only to prevent biofilm formation by planktonic cells, but also to penetrate the biofilm matrix in vitro, exerting bactericidal activity against staphylococcal sessile cells. This bacteriocin has the potential to become an alternative antimicrobial for either prevention or treatment of biofilm-related infections caused by different staphylococcal species.