What is already known about this topic?
Most Neisseria meningitidis isolates in the United States have been susceptible to antibiotics recommended for treatment and prophylaxis.
What is added by this report?
During 2019–2020, 11 meningococcal isolates from U.S. patients had isolates containing a blaROB-1 β-lactamase gene associated with penicillin resistance and mutations associated with ciprofloxacin resistance. An additional 22 cases reported during 2013–2020 contained blaROB-1 but did not have mutations associated with ciprofloxacin resistance.
What are the implications for public health practice?
Ceftriaxone and cefotaxime can continue to be used for empiric bacterial meningitis treatment; meningococcal isolate susceptibility to penicillin should be determined before switching to penicillin or ampicillin. Prophylaxis failures and antimicrobial resistance among meningococcal isolates should be monitored to inform meningococcal prophylaxis recommendations.