NAME: Neisseria meningitidis
SYNONYM OR CROSS REFERENCE: Meningococci Footnote 1, meningococcemia, meningococcal infection, meningococcal meningitis.
CHARACTERISTICS: Neisseria meningitidis belongs to the family Neisseriaceae Footnote 2. It is a Gram-negative, non-spore forming, non-motile, encapsulated, and non acid-fast diplococci, which appears in kidney bean shape under the microscope Footnote 1. Footnote 3. It requires an aerobic environment with 5% CO2 and enriched media containing blood for growth Footnote 1. Medium-sized, smooth, transparent, non-pigmented, non-hemolytic, and convex colonies are produced on blood agar after overnight incubation at 35-37°C Footnote 1. Footnote 3. It is oxidase and catalase positive Footnote 3. It has at least 12 serogroups, with serogroups A, B, C, W-135, and Y being the most commonly encountered serogroups from invasive disease cases Footnote 2. Footnote 4.
PATHOGENICITY/TOXICITY: N. meningitidis has a wide range of clinical manifestations, ranging from transient mild sore throat to fatal meningitis or meningococcal septicemia Footnote 3. Meningitis and septicemia are the most common presentations of the disease Footnote 3.
Transient meningococcemia: Patients present with mild flu-like symptoms such as fever, joint pain, and occasionally rash. The illness lasts for a few days or weeks Footnote 3.
Meningitis Footnote 1. Footnote 3: Most patients also present with signs of meningeal irritation, including, neck stiffness, bulging fontanelle (in infants), irritability, lying on one side away from light, and inability to extend the knee when hip is flexed in supine position (positive kernig’s sign) Footnote 3. Footnote 4. Convulsions, declining level of consciousness, and coma may occur Footnote 3. The petechial rash of meningococcemia may also occur Footnote 1.
Meningococcemia: Patients present with rapid onset of fever, vomiting, photophobia, convulsions, skin rash, lethargy, irritability, drowsiness, diarrhea, muscular pain, arthralgia, and rarely, acute abdominal pain Footnote 3. The characteristic meningococcal rash is due to disseminated intravascular coagulation, caused by meningococcal bacteremia, and can result in loss of digits and limbs in some cases Footnote 1. Footnote 3. Footnote 4. In severe cases patients may present with septic shock, leading to respiratory failure, renal failure, coma, and even death within 24 hrs of onset of symptoms Footnote 3. Footnote 4.
Chronic meningococcal disease: Rare manifestation of N. meningitidis infection Footnote 3. Footnote 4. Patients present with chronic intermittent high fever, joint pain, and headache, with or without skin lesions Footnote 3.
Other manifestations of N. meningitidis infection include septic arthritis; upper or lower respiratory tract infections such as otitis media, pharyngitis, bronchitis, and pneumonia; pericarditis; myocarditis; endocarditis; and conjunctivitis Footnote 3. Footnote 4.
EPIDEMIOLOGY: Worldwide. N. meningitidis causes disease in an estimated 500,000 people annually worldwide, with death in at least 10% of the affected cases Footnote 4. The worldwide incidence for endemic meningococcal disease has been reported to be 0.5–5 per 100,000 population. Ninety percent of meningococcal diseases worldwide are caused by the serogroups A, B, C. The highest incidence, with large epidemic outbreaks, has been reported for the serogroup A, in the ‘Meningitis Belt’ region of sub-Saharan Africa, affecting approximately 1,000 cases per 100,000 population and resulting in death in approximately 75% of those who are less than 15 years old during the epidemic Footnote 4. Footnote 5. In the United States, serogroups B, C, and Y are responsible for disease in children and young adults Footnote 4. Footnote 6, with the incidence of 0.5–1.1 cases per 100,000 population, or approximately 1,400–2,800 cases per year, with the highest rates in infants, and a second peak in adolescence and early adulthood Footnote 4. Since 1993, serogroups B and C have been responsible for most of the cases of endemic disease in Canada (incidence rates ranging between 0.13 to 0.65 per 100,000 population and 0.2 to 0.44 per 100,000 population for C and B respectively). From 1993 to 2003, serogroup Y incidence has remained relatively stable at 0.06 to 0.13 per 100,000 population per year. Serogroup Y disease has tended to affect older adults (median age 45 years, range 0-94). Cases of serogroup A disease remain rare in Canada (< 10 cases reported between 1993 and 2005) Footnote 7. An outbreak of disease due to N. meningitidis serogroup W135 occurred in 2000 and 2001 among pilgrims returning from the annual Islamic pilgrimage to Saudi Arabia (the Hajj) and in their contacts. For the Hajj in 2000, the attack rate of W135 disease was 25 cases per 100,000 pilgrims. After the introduction of quadrivalent meningococcal vaccine for the Hajj in 2001, no pilgrim developed W135 disease. The estimated attack rates for household contacts of returning pilgrims were 18 cases and 28 cases per 100,000 contacts for the years 2000 and 2001, respectively Footnote 8.
INFECTIOUS DOSE: Unknown.
COMMUNICABILITY: Highly contagious Footnote 1. Person-to-person transmission occurs through droplets shed from the upper respiratory tract or direct contact with oropharygeal secretions through sharing of drinks or intimate kissing; transfer via contaminated fomites has been postulated but is considered rare Footnote 4. Footnote 6. Footnote 9. An individual remains infectious as long as meningococci are present in respiratory/oral secretions or until 24 hours after initiation of effective antibiotic treatment.
RESERVOIR: Humans Footnote 1.
DRUG SUSCEPTIBILITY/RESISTANCE: Susceptible to rifampin, penicillin G, sulfonamides, and broad spectrum cephalosporins such as ceftriaxone and cefotaxime Footnote 2. Footnote 4. Strains resistant to penicillin, sulfonamides, rifampin, tetracyclines, and broad spectrum cephalosporins have been isolated. Strains resistant to chloramphenicol have been reported in Vietnam and France Footnote 2.
SUSCEPTIBILITY/RESISTANCE TO DISINFECTANTS: N. meningitidis is highly susceptible to common disinfectants Footnote 10. Common disinfectants used against vegetative bacteria include 1% sodium hypochlorite, 70% ethanol, phenolics, 2% glutaraldehyde, formaldehyde, and peracetic acid Footnote 11.
PHYSICAL INACTIVATION: It is readily inactivated by low temperatures Footnote 10. It can also be inactivated by exposure to 65°C for 5 min or 80°C for 2 min, or drying for a few hours at 20°C. Most vegetative bacteria can also be inactivated by moist heat (121°C for 15 min- 30 min) and dry heat (160-170°C for 1-2 hours) Footnote 12.
SURVIVAL OUTSIDE HOST: N. meningitidis does not survive well outside of host. It has, however, been reported to survive on glass and plastic at ambient temperatures for hours to days Footnote 9.
SURVEILLANCE: Monitor for symptoms. Culture of clinical specimens from a sterile site on blood agar with stain test can be used for diagnosis. Other methods include polymerase chain reaction (PCR), antigen detection and enzyme-linked immunosorbent assay (ELISA) Footnote 1-Footnote 4.
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: Treated with a 3-7 day course of intravenous or intramuscular penicillin or ceftriaxone Footnote 4. Other antibiotics used for treatment of meningococcal diseases include chloramphenicol, fluoroquinolones, and meropenem Footnote 4.
IMMUNIZATION: Purified capsular polysaccharide vaccines and protein-polysaccharide conjugate vaccines are available in Canada. Bivalent (A, C) and quadrivalent (A, C, Y, W135) polysaccharide vaccines are available. Conjugate vaccines include monovalent serogroup C and a quadrivalent (A, C, Y, W-135) formulation.
Meningococcal C conjugate vaccines are recommended for routine immunization of infants Footnote 7. Meningococcal vaccine is recommended for certain groups with increased risk of meningococcal disease and is also used for outbreak management.
No vaccine is currently available for serogroup B.
PROPHYLAXIS: Chemoprophylaxis is recommended for close contacts of patients with meningococcal disease, such as individuals exposed to an infected household member, daycare, or nursery school contact or anyone exposed to oral secretions from infected person Footnote 4. Chemoprophylaxis should be given within 24 hrs of diagnosis of the disease. Antibiotics used for chemoprophylaxis include oral rifampin, oral ciprofloxacin, and intramuscular ceftriaxone Footnote 4. Footnote 6. Footnote 13. Because of increasing drug resistance to ciprofloxacin in North Dakota and Minnesota, this drug is not used for chemoprophylaxis in these areas Footnote 4.
LABORATORY-ACQUIRED INFECTIONS: At least eight incidents of infection among laboratory workers with at least one death have been reported as of 1974 Footnote 14-Footnote 16 . Two fatal cases were reported in 1988 Footnote 17.
PRIMARY HAZARDS: Accidental parenteral inoculation, exposure of mucous membranes to infectious droplet nuclei or aerosols, and ingestion Footnote 15.
SPECIAL HAZARDS: None.
RISK GROUP CLASSIFICATION: Risk Group 2 Footnote 18.
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 19.
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities Footnote 19.
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up.
DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism by autoclave, chemical disinfection, gamma irradiation, or incineration before disposing.
STORAGE: All infectious materials should be stored in leak-proof containers that are appropriately labelled.
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: September 2011
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada
Although the information, opinions and recommendations contained in this Pathogen Safety Data sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Public Health Agency of Canada, 2011