Antimicrobial Resistance of Neisseria meningitidis in the United States, 1997

Neisseria meningitidis is a leading cause of meningitis and sepsis in the United States, and the case-fatality rates associated with these infections are high, despite appropriate antimicrobial therapy. Although clinical isolates resistant to penicillin have been reported since 1985, antimicrobial-resistant N. meningitidis has rarely been reported in the United States [1], and penicillin is still regarded as the antimicrobial agent of choice for treating meningococcal disease [2]. Resistance to other antimicrobial agents such as rifampin and ciprofloxacin would prompt changes in current recommendations for chemoprophylaxis [3]. We analyzed N. meningitidis isolates from an active surveillance to estimate the prevalence of infection with resistant menin-gococci. In 1997, active, population-based surveillance was conducted in 7 geographically dispersed areas of the United States (aggregate population, 26 million) [4]. A case of meningococcal disease was defined as isolation of N. meningitidis from a normally sterile site in a resident of the surveillance area. Isolates with culture dates from 7 January 1997 to 31 December 1997 were tested for susceptibility by use of the recommended broth microdilution technique [5]. All isolates not susceptible to penicillin were assayed for the production of β-lactamase by use of a chromogenic cephalosporin method.