We analyzed susceptibility patterns and β-lactamase production of 184 invasive Haemophilus influenzae disease case isolates that were submitted as part of active laboratory and population-based surveillance over a 4-year period in Minnesota. All ampicillin-resistant isolates produced β-lactamase. Rates of susceptibility to commonly used antimicrobials were high for agents other than ampicillin.
*Emerging Infections Program, Infectious Disease Epidemiology, Prevention and Control Division, and †Public Health Laboratory Division, Minnesota Department of Health, Saint Paul, MN.
Funding/Support: This surveillance is supported by the Centers for Disease Control and Prevention Emerging Infections Program Cooperative Agreement U50/CCU511190-09.
Address correspondence and reprint requests to Lori Triden, Emerging Infections Unit, Minnesota Department of Health, 625 Robert St North, Saint Paul, MN 55164-0975. E-mail: email@example.com.