title: 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.
abstract: OBJECTIVE
  Group C and group G streptococci (together GCGS) are often regarded as commensal bacteria and their role in streptococcal disease burden is under-recognized. While reports of recovery of GCGS from normally sterile body sites are increasing, their resistance to macrolides, fluoroquinolone further warrants all invasive β haemolytic streptococci to be identified to the species level and accurately tested for antimicrobial susceptibility. This study was aimed to determine the prevalence, clinical profile, antimicrobial susceptibility and streptococcal pyrogenic exotoxin gene profile (speA, speB, speC, speF, smeZ, speI, speM, speG, speH and ssa) of GCGS obtained over a period of two years at a tertiary care centre from north India.
  
  
  METHODS
  The clinical samples were processed as per standard microbiological techniques. β-haemolytic streptococci (BHS) were characterized and grouped. Antimicrobial susceptibility of GCGS was performed using disk diffusion method. All GCGS were characterized for the presence of streptococcal pyrogenic exotoxins (spe) and spe genes were amplified by PCR method.
  
  
  RESULTS
  GCGS (23 GGS, 2GCS) comprised 16 per cent of β haemolytic streptococci (25/142 βHS, 16%) isolated over the study period. Of the 25 GCGS, 22 (88%) were recovered from pus, two (8%) from respiratory tract, whereas one isolate was recovered from blood of a fatal case of septicaemia. Of the total 23 GGS isolates, 18 (78%) were identified as Streptococcus dysgalactiae subsp equisimilis (SDSE, large-colony phenotype), five (21%) were Streptococcus anginosus group (SAG, small-colony phenotype). The two GCS were identified as SDSE. All GCGS isolates were susceptible to penicillin, vancomycin, and linezolid. Tetracycline resistance was noted in 50 per cent of SDSE isolates. The rates of macrolide and fluoroquinolone resistance in SDSE were low. Twelve of the 20 SDSE isolates were positive for one or more spe genes, with five of the SDSE isolates simultaneously carrying speA+ speB+ smeZ+ speF or speB+ smeZ+speF, speI+speM+speG+speH or, speI+spe M+speH or speA+ speB+ speC+ smeZ+ speF. One notable finding was the presence of spe B in four of the five isolates of the Streptococcus anginosus group. No isolate was positive for ssa.
  
  
  CONCLUSIONS
  Our study showed no association between GCGS isolates harbouring streptococcal pyrogenic exotoxins and disease severity. This might be attributed to the small sample size of spe-positive isolates.
authors.forename: Bijayini
authors.initials: B
authors.lastname: Behera
authors.affiliation: " Department of Microbiology, JPNA Trauma Centre, AIIMS, New Delhi, India.
authors.forename: Purva
authors.initials: P
authors.lastname: Mathur
authors.forename: Nidhi
authors.initials: N
authors.lastname: Bhardwaj
authors.forename: Neetu
authors.initials: N
authors.lastname: Jain
authors.forename: M C
authors.initials: MC
authors.lastname: Misra
authors.forename: Arti
authors.initials: A
authors.lastname: Kapil
authors.forename: Sarman
authors.initials: S
authors.lastname: Singh
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D052978:Disk Diffusion Antimicrobial Tests; D024881:Drug Resistance, Bacterial / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D007194:India / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D013045:Species Specificity; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D034366:Streptococcus anginosus / Q000187:drug effects* / Q000378:metabolism; D062606:Tertiary Care Centers
chemical_list: D000900:Anti-Bacterial Agents; D001427:Bacterial Toxins; D017931:DNA Primers