Meningococcal Meningitis

 

by Jessica Vanderburg

 

Etiologic Agent: Neisseria meningitides (4)

 

Transmission: Through contact transmission, infected mucous droplets are taken into the mouth and/or nose of the patient. The droplets adhere to the oro- and nasopharynx epithelial cells and enter the bloodstream through the mucosal/blood barrier (4).

 

Reservoirs: Approximately 10% of the population carries N. meningitides in their oro- and nasopharnyx which provides a constant reservoir for the disease (2).

 

General Characteristics: Gram-negative, endotoxin producing, diplococci with flattened sides that has several different serotypes that are distinguished according to their polysaccharide capsule (4).

 

Identification Tests: N. meningitides is a Gram negative diplococcus that is oxidase positive and can ferment glucose and maltose but not lactose and sucrose. Specimens are sampled from either the blood or the cerebrospinal fluid (5).

 

Signs and Symptoms: A patient will be profoundly febrile, usually with cervical rigidity, and present with some form of neurological signs/symptoms (seizures - focal motor and/or grand mal, alteration of awareness, flaccidity of muscles, lethargy, photophobia) as result of an increase in intracranial pressure. Nausea/vomiting and headache are also common findings. The most ominous sign, however, are petechiae, purpura, and/or skin lesions/skin rash in high friction areas (skin folds, beltline, etc.) (2).    

 

Historical Information:

 

Virulence Factors: N. meningitides has an antiphagocytic polysaccharide capsule as well as an endotoxin as part of its cell wall composition (4).

 

Control/Treatment: Patients receiving treatment in a hospital should be kept in isolation with strict use of PPE until 24 hours after the initiation of appropriate therapy. Most patients require the administration of chemoprophylactics such as rifampin in conjunction with penicillin or cephalosporin (patients allergic to penicillin) (2).

 

Prevention/Vaccine: The Meningococcal Polysaccharide Vaccine (MPSV4) is formulated to attack the different polysaccharide capsules of serotypes A, C, Y, and W135 and is currently implemented in the United States to treat epidemics and populations with a high rate of contraction susceptibility (college dorms, sleep-away camps, and boarding schools, etc.). However, this vaccine is ineffective in the prevention of the disease in children under 2 years of age. Currently the Meningococcal Conjugate Vaccine (MCV4) covers the above mentioned serotypes, as well, and is licensed in the United States for people age 2 -55 years (1).

 

Local Cases or Outbreaks: There are approximately 1,400 to 2,800 documented cases of meningococcal meningitis in the United States annually (1).

 

Global Cases or Outbreaks: The prevalence of meningitis abroad, especially in some regions of Africa have been a major source of alarm with more than 2,000 cases reported thus far in 2008 (3).

 

 References

 

1. Center for Disease Control and Prevention. Factsheet: Meningococcal Diseases and Meningococcal Vaccines. March 25, 2008. http://www.cdc.gov/vaccines/vpd-vac/mening/vac-mening-fs.htm. December 6, 2008.

2. Morse, Stephen A. Medical Microbiology: Fourth Edition. Samuel Baron M.D. Neisseria, Moraxella, Kingella and Eikenella. Morse, Stephen A. http://www.gsbs.utmb.edu/microbook/ch014.htm.

3. National Center for Immunization and Respiratory Diseases: Division of Bacterial Diseases. Meningococcal Disease: Frequently Asked Questions. May, 28, 2008. http://www.cdc.gov/meningitis/bacterial/faqs.htm#meningitis. December 6, 2008.

4. Tortora, Gerard J., Funke, Berdell R., and Case, Christine L. Microbiology: An Introduction. 9th ed. San Francisco: Pearson B.C, 2007

5. WHO Collaborating Center for Prevention and Control of Epidemic Meningitis. Laboratory Methods for the Diagnosis of Meningitis Caused by Neisseria meningitides, Streptococcus pneumoniae, and Haemophilus influenzae. Center for Disease Control and Prevention. http://www.cdc.gov/meningitis/downloads/meningitis_manual.pdf. December 6th, 2008.