Utah university lab error misidentifies bacteria, sparks meningitis scare

In September 2025 a microbiology practical at a university in Utah used a bacterial sample that was supposed to be Plesiomonas shigelloides. Due to storage and labeling failures the students actually received a strain of Neisseria sicca, which produced test results that closely resembled the dangerous pathogen Neisseria meningitidis. As a result, 33 participants believed they had been exposed to the meningitis‑causing bacterium.

Health authorities recommended a ten‑day course of prophylactic antibiotics; 32 of the 33 began treatment and two individuals with mild symptoms underwent lumbar punctures, both of which returned negative for meningococcal infection. An investigation by the Utah Public Health Laboratory confirmed that no real exposure to N. meningitidis occurred. The university responded by reorganizing bacterial storage, tightening biosafety protocols and implementing new training to prevent similar mistakes.

The incident was detailed in a July report in the Morbidity and Mortality Weekly Report (MMWR).