Longitudinal assessment of antipneumococcal susceptibility in the United States

Area of Science:

• Microbiology
• Infectious Diseases
• Clinical Pharmacy

Background:

• Antimicrobial resistance (AMR) poses a significant threat to public health, complicating treatment of common bacterial infections.
• Streptococcus pneumoniae is a leading cause of bacterial pneumonia, meningitis, and sepsis, making its susceptibility patterns critical.
• Monitoring AMR trends is essential for guiding appropriate antibiotic selection and combating resistance.

Purpose of the Study:

• To determine the prevalence of antimicrobial resistance in U.S. pneumococcal isolates collected in 1999.
• To compare these resistance rates with data from a previous study conducted in 1997-1998.
• To assess trends in multidrug resistance among pneumococcal isolates.

Main Methods:

• Analysis of 4,940 U.S. pneumococcal isolates collected in 1999.
• Antimicrobial susceptibility testing against a panel of common antibiotics.
• Statistical comparison of 1999 resistance data with 1997-1998 data to identify significant changes.

Main Results:

• In 1999, resistance rates were: penicillin (16.2%), amoxicillin-clavulanate (12.2%), cefuroxime (28.1%), ceftriaxone (3.6%), trimethoprim-sulfamethoxazole (30.3%), azithromycin (21.4%), levofloxacin (0.6%), and moxifloxacin (0.1%).
• Significant increases in resistance were observed for penicillin, amoxicillin-clavulanate, cefuroxime, azithromycin, trimethoprim-sulfamethoxazole, and levofloxacin compared to 1997-1998.
• Multidrug resistance increased from 6.3% to 11.3%.

Conclusions:

• There has been a concerning increase in antimicrobial resistance among Streptococcus pneumoniae in the U.S. between 1997 and 1999.
• The rise in resistance to commonly prescribed antibiotics necessitates careful monitoring and stewardship.
• The escalating rates of multidrug resistance underscore the urgent need for strategies to preserve antibiotic efficacy.