title: Sequence diversity of sicG among group C and G Streptococcus dysgalactiae subspecies equisimilis isolates associated with human infections in western Norway.
abstract: Streptococcal inhibitor of complement (SIC) and distantly related to SIC (DRS) are well-characterized extracellular virulence factors produced by only a few emm types among group A streptococci. The prevalence and sequence variations of the sic-like gene (sicG) in clinical samples of group C and G Streptococcus dysgalactiae subspecies equisimilis (SDSE), however, have not been widely investigated. We constructed primers targeting sicG and screened 129 geographically matched and previously emm-typed non-invasive (n = 64) and invasive (n = 65) SDSE isolates for the presence of this gene. sicG was detected in seven non-invasive and eight invasive isolates belonging to eight different emm types. Within five of these emm types, sicG-negative isolates were also detected. All three isolates of stG2078.0 possessed sicG and were associated with severe soft tissue infections. Altogether, six sicG alleles (sicG1-6) were identified, and sequence variations were mainly caused by single nucleotide polymorphisms and deletion/insertion mutations. sicG1-6 were predicted to encode SICG proteins of varying length, composition, and homology with SIC and DRS proteins of group A streptococci. Our findings indicate an unpredictable association between sicG and emm type, a limited distribution and substantial sequence diversity of sicG, and no obvious relation between its presence and disease severity.
authors.affiliation: Department of Medicine, Haukeland University Hospital, Jonas Lies vei 1, 5021, Bergen, Norway, Oddvar.Oppegaard@helse-bergen.no.
authors.forename: O
authors.initials: O
authors.lastname: Oppegaard
authors.forename: H
authors.initials: H
authors.lastname: Mylvaganam
authors.forename: S
authors.initials: S
authors.lastname: Skrede
authors.forename: N
authors.initials: N
authors.lastname: Langeland
authors.forename: B R
authors.initials: BR
authors.lastname: Kittang
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009664:Norway / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013291:Streptococcus / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial
references.citation: Biochem Soc Trans. 2006 Apr;34(Pt 2):273-5
references.pmid: 16545092
references.citation: Curr Microbiol. 2011 Mar;62(3):884-7
references.pmid: 21046393
references.citation: J Clin Microbiol. 2003 Apr;41(4):1794-7
references.pmid: 12682191
references.citation: BMC Genomics. 2012 Aug 17;13:404
references.pmid: 22900646
references.citation: Proc Natl Acad Sci U S A. 1998 Mar 17;95(6):3128-33
references.pmid: 9501227
references.citation: Infect Immun. 2000 Feb;68(2):535-42
references.pmid: 10639414
references.citation: Microb Pathog. 2001 Feb;30(2):71-9
references.pmid: 11162187
references.citation: Infect Immun. 2004 Jul;72(7):3981-6
references.pmid: 15213143
references.citation: Eur J Clin Microbiol Infect Dis. 2011 Mar;30(3):423-33
references.pmid: 21103900
references.citation: J Biol Chem. 1996 Jan 12;271(2):1081-8
references.pmid: 8557634
references.citation: Clin Microbiol Infect. 2010 Aug;16(8):1097-103
references.pmid: 19732082
references.citation: Infect Immun. 2002 Sep;70(9):4908-16
references.pmid: 12183536
references.citation: Genome Biol Evol. 2011;3:168-85
references.pmid: 21282711
references.citation: Clin Infect Dis. 2009 Mar 15;48(6):706-12
references.pmid: 19187026
references.citation: PLoS One. 2008 Aug 21;3(8):e3026
references.pmid: 18716664
references.citation: BMC Genomics. 2011 Jan 11;12:17
references.pmid: 21223537
references.citation: J Clin Microbiol. 2009 Jul;47(7):2046-54
references.pmid: 19386831
references.citation: Clin Microbiol Infect. 2011 Mar;17(3):358-64
references.pmid: 20456456
references.citation: Clin Infect Dis. 2007 Jun 1;44(11):1442-54
references.pmid: 17479940
references.citation: Microb Pathog. 1999 Jan;26(1):25-33
references.pmid: 9973578