Antibiotic resistance patterns in invasive group B streptococcal isolates.

Area of Science:

• Microbiology
• Infectious Diseases
• Public Health Surveillance

Background:

• Group B Streptococcus (GBS) is a significant cause of invasive disease in various populations.
• Antibiotics are crucial for GBS prevention and treatment, necessitating ongoing surveillance of antimicrobial susceptibility.
• Understanding resistance patterns is vital for effective GBS management strategies.

Purpose of the Study:

• To assess the antimicrobial susceptibility patterns of invasive Group B Streptococcus isolates.
• To identify trends in antibiotic resistance, particularly to clindamycin and erythromycin, from 1996 to 2003.
• To investigate the association between GBS serotypes and antibiotic resistance.

Main Methods:

• Population-based surveillance of invasive GBS disease was conducted across four US states.
• Isolates underwent serotyping and antimicrobial susceptibility testing.
• Statistical analyses were performed to identify trends and associations, including inducible clindamycin resistance and erm genotype.

Main Results:

• All GBS isolates tested remained susceptible to penicillin, ampicillin, cefazolin, cefotaxime, and vancomycin.
• Resistance to clindamycin was 12.7% and increased from 10.5% to 15.0% during the study period.
• Erythromycin resistance was 25.6% and significantly increased from 15.8% to 32.8%, with both resistances associated with serotype V.

Conclusions:

• Group B Streptococcus remains highly susceptible to beta-lactam antibiotics like penicillin and ampicillin.
• Increasing resistance to clindamycin and erythromycin, particularly inducible clindamycin resistance linked to the erm genotype, is a significant concern for GBS treatment.
• Continued surveillance is essential to monitor evolving antibiotic resistance patterns in GBS.