26.2 Bacterial diseases of the nervous system  (Page 3/20)

Because meningococcoal meningitis progresses so rapidly, a greater variety of clinical specimens are required for the timely detection of N. meningitidis . Required specimens can include blood, CSF, naso- and oropharyngeal swabs, urethral and endocervical swabs, petechial aspirates, and biopsies. Safety protocols for handling and transport of specimens suspected of containing N. meningitidis should always be followed, since cases of fatal meningococcal disease have occurred in healthcare workers exposed to droplets or aerosols from patient specimens. Prompt presumptive diagnosis of meningococcal meningitis can occur when CSF is directly evaluated by Gram stain, revealing extra- and intracellular gram-negative diplococci with a distinctive coffee-bean microscopic morphology associated with PMNs ( [link] ). Identification can also be made directly from CSF using latex agglutination and immunochromatographic rapid diagnostic tests specific for N. meningitidis . Species identification can also be performed using DNA sequence-based typing schemes for hypervariable outer membrane proteins of N. meningitidis , which has replaced sero(sub)typing.

Meningococcal infections can be treated with antibiotic therapy, and third-generation cephalosporins are most often employed. However, because outcomes can be negative even with treatment, preventive vaccination is the best form of treatment. In 2010, countries in Africa’s meningitis belt began using a new serogroup A meningococcal conjugate vaccine. This program has dramatically reduced the number of cases of meningococcal meningitis by conferring individual and herd immunity.

Twelve different capsular serotypes of N. meningitidis are known to exist. Serotypes A, B, C, W, X, and Y are the most prevalent worldwide. The CDC recommends that children between 11–12 years of age be vaccinated with a single dose of a quadrivalent vaccine that protects against serotypes A, C, W, and Y, with a booster at age 16. US Centers for Disease Control and Prevention, “Recommended Immunization Schedule for Persons Aged 0 Through 18 Years, United States, 2016,” February 1, 2016. Accessed on June 28, 2016. http://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html. An additional booster or injections of serogroup B meningococcal vaccine may be given to individuals in high-risk settings (such as epidemic outbreaks on college campuses).

Meningitis on campus

College students living in dorms or communal housing are at increased risk for contracting epidemic meningitis. From 2011 to 2015, there have been at least nine meningococcal outbreaks on college campuses in the United States. These incidents involved a total of 43 students (of whom four died). National Meningitis Association, “Serogroup B Meningococcal Disease Outbreaks on U.S. College Campuses,” 2016. Accessed June 28, 2016. http://www.nmaus.org/disease-prevention-information/serogroup-b-meningococcal-disease/outbreaks/. In spite of rapid diagnosis and aggressive antimicrobial treatment, several of the survivors suffered from amputations or serious neurological problems.

Prophylactic vaccination of first-year college students living in dorms is recommended by the CDC, and insurance companies now cover meningococcal vaccination for students in college dorms. Some colleges have mandated vaccination with meningococcal conjugate vaccine for certain students entering college ( [link] ).