Laboratory Acquired Meningococcal Disease
Although Neisseria Meningitidis is regularly isolated in clinical laboratories it has infrequently been reported as a cause of laboratory acquired infection. Neisseria Meningitidis isolates pose a risk for laboratory workers and should be handled in a manner that minimises risk of exposure to aerosols or droplets.
Control Measures
Neisseria meningitidis is classed as a biosafety level 2 organism. Guidelines recommend the use of a biosafety cabinet for mechanical manipulations of samples that have a substantial risk that droplet formation or aerosolisation such as centrifuging, grinding and blending procedures. Exposure to isolates of Neisseria meningitidis increases the risk infection. Manipulating suspensions of Neisseria meningitidis outside a biosafety cabinet is associated with a high risk of contracting the disease. If a biosafety cabinet or other means of protection is unavailable, manipulation of these isolates should be minimised, and workers should consider sending specimens to laboratories possessing this equipment.
Vaccination
Laboratory workers should make informed decisions about vaccination. The quadrivalent meningococcal polysaccharide vaccine, which includes serogroups A, C, Y and W135 will decrease but not eliminate the risk of infection.
Action in the Event of an Exposure
Laboratory scientists with percutaneous exposure to an invasive Neisseria meningitidis isolate should receive treatment with penicillin; those with known inadvertent mucosal exposure should receive antimicrobial chemoprophylaxis as soon as possible after the exposure. The current recommended chemoprophylaxis is ciprofloxacin (contra-indicated in pregnancy) but this should be discussed with the Occupational Health Physician within working hours or the on-call microbiologist at the John Radcliffe Hospital if exposure occurs out of working hours.
Chemoprophylaxis
Microbiologists who manipulate invasive Neisseria meningitidis isolates in a manner that could induce aerosolisation or droplet formation on an open benchtop and in the absence of effective protection from droplets or aerosols should consider antimicrobial chemoprophylaxis.
Ref: Laboratory-Acquired Meningococcal Disease --- United States, 2000 MMWR Weekly Feb 22, 2002/ 51 (07) ; 141-4