title: Comparative analysis of emm type pattern of Group A Streptococcus throat and skin isolates from India and their association with closely related SIC, a streptococcal virulence factor.
abstract: BACKGROUND
  Group A streptococcus (GAS) causes a wide variety of life threatening diseases in humans and the incidence of such infections is high in developing countries like India. Although distribution of emm types of GAS in India has been described, there is a lack of data describing either the comparative distribution of emm types in throat versus skin isolates, or the distribution of certain virulence factors amongst these isolates. Therefore in the present study we have monitored the emm type pattern of Group A streptococcus throat and skin isolates from India. Additionally, the association of these isolates with closely related sic (crs), a multifunctional compliment binding virulence factor, was also explored.
  
  
  RESULTS
  Of the 94 (46 throat and 48 skin) isolates analyzed, 37 emm types were identified. The most frequently observed emm types were emm49 (8.5%) and emm112 (7.5%) followed by 6.5% each of emm1-2, emm75, emm77, and emm81. Out of 37 emm types, 27 have been previously reported and rest were isolated for the first time in the Indian Community. The predominant emm types of throat (emm49 and emm75) samples were different from those of skin (emm44, emm81 and emm112) samples. After screening all the 94 isolates, the crs gene was found in six emm1-2 (crs1-2) isolates, which was confirmed by DNA sequencing and expression analysis. Despite the polymorphic nature of crs, no intravariation was observed within crs1-2. However, insertions and deletions of highly variable sizes were noticed in comparison to CRS isolated from other emm types (emm1.0, emm57). CRS1-2 showed maximum homology with CRS57, but the genomic location of crs1-2 was found to be the same as that of sic1.0. Further, among crs positive isolates, speA was only present in skin samples thus suggesting possible role of speA in tissue tropism.
  
  
  CONCLUSIONS
  Despite the diversity in emm type pattern of throat and skin isolates, no significant association between emm type and source of isolation was observed. The finding that the crs gene is highly conserved even in two different variants of emm1-2 GAS (speA +ve and -ve) suggests a single allele of crs may be prevalent in the highly diverse throat and skin isolates of GAS in India.
authors.affiliation: Department of Experimental Medicine & Biotechnology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India. vivekbiotech@rediffmail.com
authors.forename: Vivek
authors.initials: V
authors.lastname: Sagar
authors.forename: Rajesh
authors.initials: R
authors.lastname: Kumar
authors.forename: Nirmal K
authors.initials: NK
authors.lastname: Ganguly
authors.forename: Anuradha
authors.initials: A
authors.lastname: Chakraborti
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000145:classification / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000145:classification / Q000235:genetics*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D015373:Bacterial Typing Techniques; D002352:Carrier Proteins / Q000145:classification / Q000235:genetics*; D005098:Exotoxins / Q000235:genetics; D006801:Humans; D007194:India; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D010614:Pharynx / Q000382:microbiology*; D010802:Phylogeny; D016415:Sequence Alignment; D012867:Skin / Q000382:microbiology*; D017192:Skin Diseases, Bacterial / Q000382:microbiology*; D013290:Streptococcal Infections / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D005098:Exotoxins; D008565:Membrane Proteins; C117980:SpeA protein, Streptococcus pyogenes; D037521:Virulence Factors; C014689:streptococcal M protein
references.citation: J Clin Invest. 1999 May;103(9):1261-8
references.pmid: 10225969
references.citation: Lett Appl Microbiol. 2002;35(3):237-41
references.pmid: 12180948
references.citation: Lett Appl Microbiol. 2004;39(1):84-8
references.pmid: 15189292
references.citation: J Clin Microbiol. 2003 Mar;41(3):937-42
references.pmid: 12624012
references.citation: Proc Natl Acad Sci U S A. 1998 Mar 17;95(6):3128-33
references.pmid: 9501227
references.citation: Indian J Med Microbiol. 2001 Jul-Sep;19(3):161-2
references.pmid: 17664825
references.citation: J Clin Microbiol. 2003 Jan;41(1):373-8
references.pmid: 12517875
references.citation: Infect Immun. 2003 Dec;71(12):6701-6
references.pmid: 14638753
references.citation: Infect Immun. 2002 Apr;70(4):2171-7
references.pmid: 11895984
references.citation: J Infect Dis. 2004 Feb 15;189(4):717-23
references.pmid: 14767827
references.citation: Methods Enzymol. 1996;266:383-402
references.pmid: 8743695
references.citation: J Clin Microbiol. 1997 Dec;35(12):3220-4
references.pmid: 9399523
references.citation: J Infect Dis. 2003 Nov 15;188(10):1587-92
references.pmid: 14624386
references.citation: Lancet. 2002 Mar 9;359(9309):889
references.pmid: 11897311
references.citation: J Clin Microbiol. 2002 Oct;40(10):3835-7
references.pmid: 12354893
references.citation: N Engl J Med. 1991 Sep 12;325(11):783-93
references.pmid: 1870652
references.citation: Indian Heart J. 1995 Jul-Aug;47(4):395-8
references.pmid: 8557287
references.citation: J Bacteriol. 2004 Jul;186(13):4285-94
references.pmid: 15205431
references.citation: J Clin Microbiol. 2006 Jun;44(6):2160-6
references.pmid: 16757615
references.citation: J Biol Chem. 2003 May 9;278(19):16561-6
references.pmid: 12621031
references.citation: Microb Pathog. 1999 Jan;26(1):25-33
references.pmid: 9973578
references.citation: Infection. 2001 May-Jun;29(3):163-5
references.pmid: 11440388
references.citation: J Clin Microbiol. 2005 Sep;43(9):4369-76
references.pmid: 16145079
references.citation: J Bacteriol. 2007 Apr;189(7):2933-5
references.pmid: 17237170
references.citation: Microbiol Immunol. 2002;46(7):419-23
references.pmid: 12222927
references.citation: Clin Infect Dis. 2005 Jan 1;40(1):46-51
references.pmid: 15614691
references.citation: Clin Microbiol Rev. 2000 Jul;13(3):470-511
references.pmid: 10885988
references.citation: J Biol Chem. 1996 Jan 12;271(2):1081-8
references.pmid: 8557634
references.citation: J Infect Dis. 2000 Nov;182(5):1425-36
references.pmid: 11015234
references.citation: Emerg Infect Dis. 1999 Mar-Apr;5(2):254-63
references.pmid: 10221878
references.citation: J Microbiol Immunol Infect. 2005 Apr;38(2):105-11
references.pmid: 15843854
references.citation: Infect Immun. 2002 Sep;70(9):4908-16
references.pmid: 12183536