Conjugative transfer of the erm(A) gene from erythromycin-resistant Streptococcus pyogenes to macrolide-susceptible S. pyogenes, Enterococcus faecalis and Listeria innocua

Area of Science:

• Microbiology
• Genetics
• Molecular Biology

Background:

• Macrolide resistance is a growing public health concern.
• The erm(A) gene is a common determinant of macrolide resistance.
• Understanding gene transfer mechanisms is crucial for combating antibiotic resistance.

Purpose of the Study:

• To investigate the transferability of the erythromycin resistance methylase (erm(A)) gene.
• To determine if erm(A) can be transferred from clinical isolates of Streptococcus pyogenes to other bacteria.
• To analyze genetic changes in recipient strains following gene transfer.

Main Methods:

• Mating experiments were conducted using erm(A)-positive Streptococcus pyogenes clinical isolates.
• Macrolide-susceptible recipients included S. pyogenes, Enterococcus faecalis, and Listeria innocua.
• SmaI macrorestriction fragment analysis was used to compare DNA patterns of recipients and transconjugants.

Main Results:

• Successful transfer of the erm(A) gene from S. pyogenes to S. pyogenes, E. faecalis, and L. innocua was achieved.
• S. pyogenes transconjugants exhibited altered SmaI macrorestriction patterns, including loss of a fragment and gain of a larger fragment.
• This demonstrates the mobility of the erm(A) gene across different Gram-positive species.

Conclusions:

• The erm(A) gene is transferable between S. pyogenes strains and to other Gram-positive bacteria.
• Horizontal gene transfer contributes to the spread of macrolide resistance.
• Further research is needed to understand the implications of erm(A) gene mobility in clinical settings.