Korean J Clin Microbiol.  2004 Mar;7(1):27-30.

Clonality Analysis Using Pulsed-Field Gel Electrophoresis of Erythromycin Resistant Group A Streptococci

• Lee NY
• Koh EH
• Kim S

Abstract

BACKGROUND: Antibiotic resistance of group A streptococci (GAS) is increasing nationwide. Pulsed-field gel electrophoresis (PFGE) is useful for investigating genetic relationship among outbreaks of bacterial infection. Erythromycin (EM) resistance is mediated by either ermB, ermTR, or mefA gene.The emm gene encodes M protein which is the most important virulence factor of GAS.
METHODS
The clonal relationship among 56 EM resistant GAS isolated from the children with acute pharyngitis in Jinju was investigated by analysis of chromosomal DNA restriction pattern with SmaI enzyme. The ermB and mefA genes were amplified and emm genotype was identified with PCR and sequencing. Their relationship with PFGE pattern was investigated.
RESULTS
The emm genotyes were identified as 2, 3, 12, 18, and 75. Mostly emm12 had ermB gene, while emm 3, 18 and 75 had mefA resistance gene. All strains with mefA gene were not restricted with SmaI. The emm12 strains showed 5 different PFGE patterns.
CONCLUSIONS
The emm genotypes were closely related with resistance genes. Analysis of macrorestriction fragment patterns by PFGE showed that EM resistant GAS were polyclonal at least in Jinju. GAS strains with mefA gene were not restricted with SmaI suggesting mefA gene might inhibit chromosomal digestion with SmaI.

Keyword

Group A streptococci; PFGE; Erythromycin resistance; Clonality

MeSH Terms

Bacterial Infections
Child
Digestion
Disease Outbreaks
DNA
Drug Resistance, Microbial
Electrophoresis, Gel, Pulsed-Field*
Erythromycin*
Genotype
Gyeongsangnam-do
Humans
Pharyngitis
Polymerase Chain Reaction
Virulence
DNA
Erythromycin