Pneumococci resistant to erythromycin

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Streptococcus pneumoniae (pneumococci) are a leading cause of bacterial infections.
• Erythromycin is a crucial antibiotic for treating pneumococcal infections.
• Monitoring antibiotic resistance is vital for public health.

Purpose of the Study:

• To determine the prevalence and characteristics of erythromycin-resistant pneumococci.
• To track the emergence and spread of erythromycin resistance in pneumococci.
• To assess the susceptibility of resistant strains to other antibiotics.

Main Methods:

• Isolation and susceptibility testing of pneumococci from clinical specimens.
• Monitoring erythromycin resistance from 1969 to 1977.
• Characterization of resistant strains, including capsular typing and MIC determination.
• Testing resistance to lincomycin, clindamycin, and penicillin.

Main Results:

• Erythromycin resistance emerged in pneumococci isolates after October 1973.
• 0.71% (64/8995) of isolates were resistant between October 1973 and December 1977.
• Resistant strains were found in multiple communities and represented nine capsular types.
• Some strains showed high-level resistance (MIC 2000 µg/mL) to erythromycin, lincomycin, and clindamycin.
• All resistant strains remained susceptible to penicillin.

Conclusions:

• Erythromycin resistance in pneumococci emerged in Alberta during the study period.
• The emergence of resistance involved diverse capsular types, some previously unreported.
• High-level resistance to erythromycin, lincomycin, and clindamycin was observed in specific strains.
• Penicillin remains an effective treatment option for erythromycin-resistant pneumococcal infections.