Related Experiment Videos
The emergence of erythromycin resistance in Streptococcus pyogenes in Fremantle, Western Australia
N Stingemore1, G R Francis, M Toohey
1Department of Microbiology, Fremantle Hospital, WA.
Abstract:
Erythromycin resistance in Streptococcus pyogenes is unusual except in Japan. Since January 1, 1985, a dramatic increase has occurred in the prevalence of erythromycin-resistant Strept. pyogenes infections in the outpatients who have presented to Fremantle Hospital, Western Australia. In 1985, 1% of isolates of Strept. pyogenes was erythromycin-resistant. This had risen to 9.1% of isolates in 1986 and to 17.6% of isolates in 1987. Several M- and T-types of Strept. pyogenes were involved. Treatment failure now can be expected when erythromycin is prescribed for the treatment of common infections in outpatients at this hospital. Laboratories that use disc methods of antimicrobial susceptibility testing may not detect erythromycin resistance in these organisms.
Insights
Erythromycin resistance in Streptococcus pyogenes is increasing significantly in Western Australia. This rise impacts outpatient treatment effectiveness and may be missed by standard lab tests.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Erythromycin resistance in Streptococcus pyogenes is typically rare globally, with notable exceptions in Japan.
- A significant increase in erythromycin-resistant Streptococcus pyogenes infections has been observed in outpatients.
Purpose of the Study:
- To document the rising prevalence of erythromycin-resistant Streptococcus pyogenes infections in outpatients.
- To assess the implications of this resistance on treatment outcomes and diagnostic methods.
Main Methods:
- Retrospective analysis of Streptococcus pyogenes isolates from outpatients at Fremantle Hospital, Western Australia, between January 1, 1985, and December 31, 1987.
- Antimicrobial susceptibility testing of isolates to erythromycin.
Main Results:
- Erythromycin resistance in Streptococcus pyogenes isolates increased from 1% in 1985 to 9.1% in 1986 and 17.6% in 1987.
- Multiple M- and T-types of Streptococcus pyogenes were implicated in the resistance.
- Standard disc diffusion methods may not reliably detect erythromycin resistance in these strains.
Conclusions:
- Erythromycin resistance in Streptococcus pyogenes has dramatically increased in outpatients at Fremantle Hospital.
- Treatment failures can be anticipated when prescribing erythromycin for common infections in this setting.
- Laboratories should be aware of potential limitations in detecting erythromycin resistance using standard disc methods.