The molecular epidemiological characteristics of streptococci isolated from primary school children in Vietnam

Objectives. The goal of the study was to isolate group A, С, and G streptococci from children and characterize them by the methods of molecular epidemiology.

Materials and methods. Group A, С, and G streptococci were isolated from tonsils and back wall of pharynx of Vietnamese children during 2012–2014. сpn60 gene based PCR approach and rnpB gene sequencing were used to identify streptococcal species belonging to group С and G streptococci. The presence of scpA, lmb, nga, slo virulence genes was analyzed in S. anginosus and S. dysgalactiae subsp. equisimilis strainS. emm-typing of S. pyogenes was done as published (http://www.cdc.gov/ncidod/biotech/strep/MProteinGene_typing.htm). Antibiotic resistance of the strains was tested by the disk diffusion method.

Results. A total of 1359 children were examined. Group A streptococci (S. pyogenes) were isolated from 49 children, group C streptococci – from 8 children (4 stains – S. anginosus, 1 strain – S. dysgalactiae subsp. equisimilis, 1 strain – S. parasanguinis, 1 strain – S. gordonii, 1 strain – S. constellatus), and group G streptococci – from 75 children (55 stains – S. anginosus, 8 stains – S. dysgalactiae subsp. equisimilis, 4 stains – S. sanguinis, 3 stains – S. parasanguinis, 2 stains – S. australis, 2 stains – S. constellatus, 1 stain – S. mitis). emm-typing of 47 S. pyogenes strains revealed 15 different emm-subtypes belonging to 11 different emm-typeS. The subtypes emm104.0 and emm109.1 were found to be predominant. S. anginosus strains under study were genetically heterogeneous for the presence of virulence genes. All tested strains were susceptible to cephalosporins and vancomycin, and resistant to amikacine. A total of 70% and 52,5% of S. pyogenes were resistant to tetracycline and erythromycin, respectively.

1. Lindbaek M, Hoiby EA, Lermark G, Steinsholt IM, Hjortdahl P. Clinical symptoms and signs in sore throat patients with large colony variant beta-haemolytic streptococcoi groups C or G versus group A. British Journal of General Practice. 2005 Aug;55(517):615-9.

2. Finger R, Ho SH, Ngo TT, Ritchie CD, Nguyen TN. Rapid streptococcal testing in Vietnamese children with pharyngitiS. Asia-Pacific journal of public health / Asia-Pacific Academic Consortium for Public Health. 1999;11(1):26-9.

3. Il’yasov Yu. Clinicheskaya laboratornaya diagnostika. 2011;2:40-3 (in Russian).

4. Franken C, Haase G, Brandt C, et al. Horizontal gene transfer and host specificity of beta-haemolytic streptococci: the role of a putative composite transposon containing scpB and lmb. Molecular Microbiology. 2001 Aug;41(4):925-35.

5. Asam D, Spellerberg B. Molecular pathogenicity of Streptococcus anginosuS. Molecular Oral Microbiology. 2014 Aug;29(4):145-55.

6. Tapp J, Thollesson M, Herrmann B. Phylogenetic relationships and genotyping of the genus Streptococcus by sequence determination of the RNase P RNA gene, rnpB. nternational Journal of Systematic and Evolutionary Microbiology. 2003 Nov;53:1861-71.

7. Geyer A, Schmidt KH. Genetic organisation of the M protein region in human isolates of group C and G streptococci: two types of multigene regulator-like (mgrC) regionS. Molecular and General GeneticS. 2000 Jan;262(6):965-76.

8. Chang YC, Lo HH. Identification, clinical aspects, susceptibility pattern, and molecular epidemiology of beta-haemolytic group G Streptococcus anginosus group isolates from central Taiwan. Diagnostic Microbiology and Infectious Disease. 2013 Jul;76(3):262-5.

9. Kozlov R.S. Clinicheskaya microbiologiya i antimicrobnaya himioterapiya. – 2005; 7(2):154-66 (in Russian).

10. Bramhachari PV, Kaul SY, McMillan DJ, Shaila MS, Karmarkar MG, Sriprakash KS. Disease burden due to Streptococcus dysgalactiae subsp equisimilis (group G and C streptococcus) is higher than that due to Streptococcus pyogenes among Mumbai school children. Journal of Medical Microbiology. 2010 Feb;59(2):220-3.

11. Shulman ST, Tanz RR, Kabat W, et al. Group A streptococcal pharyngitis serotype surveillance in North America, 2000-2002. Clinical Infectious DiseaseS. 2004 Aug;39(3):325-32.

12. Steer AC, Magor G, Jenney AWJ, et al. emm and C-Repeat Region Molecular Typing of Beta-Hemolytic Streptococci in a Tropical Country: Implications for Vaccine Development. Journal of Clinical Microbiology. 2009 Aug;47(8):2502-9.

13. Wu PC, Lo WT, Chen SJ, Wang CC. Molecular characterization of Group A streptococcal isolates causing scarlet fever and pharyngitis among young children: A retrospective study from a northern Taiwan medical center. Journal of Microbiology Immunology and Infection. 2014 Aug;47(4):304-10.

14. Tewodros W, Kronvall G. M protein gene (emm type) analysis of group a beta-hemolytic streptococci from Ethiopia reveals unique patternS. Journal of Clinical Microbiology. 2005 Sep;43(9):4369-76.

15. Hu MC, Walls MA, Stroop SD, Reddish MA, Beall B, Dale JB. Immunogenicity of a 26-valent group A streptococcal vaccine. Infection and Immunity. 2002 Apr;70(4):2171-7.

16. Dale JB, Penfound TA, Tamboura B, et al. Potential coverage of a multivalent M protein-based group A streptococcal vaccine. Vaccine. 2013 Mar;31(12):1576-81.

17. Vohra H, Dey N, Gupta S, et al. M protein conserved region antibodies opsonise multiple strains of Streptococcus pyogenes with sequence variations in C-repeatS. Research in Microbiology. 2005 May;156(4):575-82.

18. Behera B, Mathur P, Bhardwaj N, et al. Antibiotic susceptibilities, streptococcal pyrogenic exotoxin gene profiles among clinical isolates of group C or G Streptococcus dysgalactiae subsp equisimilis & of group G S. anginosus group at a tertiary care centre. Indian Journal of Medical Research. 2014 Mar;139:438-45.

19. Asmah N, Eberspaecher B, Regnath T, Arvand M. Prevalence of erythromycin and clindamycin resistance among clinical isolates of the Streptococcus anginosus group in Germany. Journal of Medical Microbiology. 2009 Feb;58(2):222-7.

20. Ip M, Lyon DJ, Leung T, Cheng AFB. Macrolide resistance and distribution of erm and mef genes among beta-haemolytic streptococci in Hong Kong. European Journal of Clinical Microbiology & Infectious DiseaseS. 2002 Mar;21(3):238-40.

21. Brown DFJ, Hope R, Livermore DM, et al. Non-susceptibility trends among enterococci and non-pneumococcal streptococci from bacteraemias in the UK and Ireland, 2001-06. Journal of Antimicrobial Chemotherapy. 2008 Nov;62:II75-85.

22. Biedenbach DJ, Toleman MA, Walsh TR, Jones RN. Characterization of fluoroquinolone-resistant beta-hemolytic Streptococcus spp. isolated in North America and Europe including the first report of fluoroquinolone-resistant Streptococcus dysgalactiae subspecies equisimilis: Report from the SENTRY Antimicrobial Surveillance Program (1997- 2004). Diagnostic Microbiology and Infectious Disease. 2006 Jun;55(2):119-27.