title: Suicin 90-1330 from a nonvirulent strain of Streptococcus suis: a nisin-related lantibiotic active on gram-positive swine pathogens.
abstract: Streptococcus suis serotype 2 is known to cause severe infections (meningitis, endocarditis, and septicemia) in pigs and is considered an emerging zoonotic agent. Antibiotics have long been used in the swine industry for disease treatment/prevention and growth promoters. This pattern of utilization resulted in the spread of antibiotic resistance in S. suis worldwide. Interestingly, pigs may harbor S. suis in their tonsils without developing diseases, while North American strains belonging to the sequence type 28 (ST28) are nonvirulent in animal models. Consequently, the aim of this study was to purify and characterize a bacteriocin produced by a nonvirulent strain of S. suis serotype 2, with a view to a potential therapeutic and preventive application. S. suis 90-1330 belonging to ST28 and previously shown to be nonvirulent in an animal model exhibited antibacterial activity toward all S. suis pathogenic isolates tested. The bacteriocin produced by this strain was purified to homogeneity by cationic exchange and reversed-phase fast protein liquid chromatography. Given its properties (molecular mass of <4 kDa, heat, pH and protease stability, and the presence of modified amino acids), the bacteriocin, named suicin 90-1330, belongs to the lantibiotic class. Using a DNA-binding fluorophore, the bacteriocin was found to possess a membrane permeabilization activity. When tested on other swine pathogens, the suicin showed activity against Staphylococcus hyicus and Staphylococcus aureus, whereas it was inactive against all Gram-negative bacteria tested. Amino acid sequencing of the purified bacteriocin showed homology (90.9% identity) with nisin U produced by Streptococcus uberis. The putative gene cluster involved in suicin production was amplified by PCR and sequence analysis revealed the presence of 11 open reading frames, including the structural gene and those required for the modification of amino acids, export, regulation, and immunity. Further studies will evaluate the ability of suicin 90-1330 or the producing strain to prevent experimental S. suis infections in pigs.
authors: Groupe de Recherche en Écologie Buccale, Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec, Canada.
authors: Geneviève
authors: G
authors: LeBel
authors: Groupe de Recherche en Écologie Buccale, Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec, Canada.
authors: Katy
authors: K
authors: Vaillancourt
authors: Groupe de Recherche en Écologie Buccale, Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec, Canada Centre de Recherche en Infectiologie Porcine et Avicole, Fonds de Recherche du Québec-Nature et Technologies, Quebec City, Quebec, Canada.
authors: Michel
authors: M
authors: Frenette
authors: Centre de Recherche en Infectiologie Porcine et Avicole, Fonds de Recherche du Québec-Nature et Technologies, Quebec City, Quebec, Canada Groupe de Recherche sur les Maladies Infectieuses du Porc, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada.
authors: Marcelo
authors: M
authors: Gottschalk
authors: Groupe de Recherche en Écologie Buccale, Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec, Canada Centre de Recherche en Infectiologie Porcine et Avicole, Fonds de Recherche du Québec-Nature et Technologies, Quebec City, Quebec, Canada daniel.grenier@greb.ulaval.ca.
authors: Daniel
authors: D
authors: Grenier
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001430:Bacteriocins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D053898:Biosynthetic Pathways / Q000235:genetics; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D002853:Chromatography, Liquid; D006090:Gram-Negative Bacteria / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D008970:Molecular Weight; D005810:Multigene Family; D009561:Nisin / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010539:Permeability / Q000187:drug effects; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000187:drug effects*; D057788:Staphylococcus hyicus / Q000187:drug effects*; D017011:Streptococcus suis / Q000737:chemistry*; D013552:Swine
chemical_list: D001430:Bacteriocins; D009561:Nisin