Neisseria meningitidis

History In 1884 Ettore Marchiafava and An gelo Celli first observed the bacterium inside cells in the cerebral spinal fluidEttore MarchiafavaAn gelo Cellicerebral spinal fluid Ettore Marchiafava Ettore Marchiafava

History Diplococcu s intracellularis meningitidis In 1887 Anton Weichselbaum isolated the bacterium from the CSF of patients with bacterial meningitis. He named the bacterium Diplococcu s intracellularis meningitidis.Anton Weichselbaum Anton Weichselbaum Anton Weichselbaum

The bacterium is referred to as a coccus because it is round, and more specifically, diplococcus because of its tendency to form pairs. coccus diplococcus

Neisseria meningitidis parasitic, aerobic, Gram-negative, non endospore forming, nonmotile (although piliated) Neisseria meningitidis is a parasitic, aerobic, Gram-negative, non endospore forming, nonmotile (although piliated), coccal bacterium that is responsible for causing meningitis, inflammation of the meninges layer covering the brain.

Pili

smooth, moist, and glistening Colonies appear smooth, moist, and glistening

Subtypes Disease-causing strains are classified according to the antigenic structure of their polysaccharide capsule. Among the 13 identified capsular types of N. meningitidis, six (A, B, C, W135, X, and Y) account for most disease cases worldwide.Type A has been the most prevalent in Africa and Asia, but is rare/ practically absent in North America. In the United States, serogroup B is the predominant cause of disease and mortality, followed by serogroup C. The multiple subtypes have hindered development of a universal vaccine for meningococcal disease.antigenicpolysaccharide

Virulence Lipooligosaccharide Virulence Virulence Lipooligosaccharide (LOS) is a component of the outer membrane of N. meningitidis. This acts as an endotoxin and is responsible for septic shock and hemorrhage due to the destruction of red blood cells. outer membrane endotoxin septic shock

Lipooligosaccharide Lipooligosaccharide (LOS)

About 10% of adults are carriers of the bacteria in their nasopharynxnasopharynx N. meningitidis is a part of the normal nonpathogenic flor a in the nasopharynx of up to 5–15% of adults. It colonizes and infects only humans, and has never been isolated from other animals.nonpathogenicnasopharynx

Patology saliva respiratory secretions N. meningitidis is spread through saliva and respiratory secretions during coughing, sneezing, kissing, and chewing on toys

Neisseria meningitidis is often transferred from person to person in aerosol form as from a sneeze.

Upon infection, it first takes residence on the muscosal membrane surface as in the nose, throat, and respiratory tract by attaching with its pili.

tissue bloodstream brain It then gradually infects deeper into the tissue until it gains access to the bloodstream where it then travels to infect the meninges of the brain.

Brain

21 upper respiratory tractinfection upper respiratory tract infection – adhesion pili bloodstream bloodstream brain Neisseria meningitidis

Following dissemination of virulent organisms from the nasopharynx: Meningitis Septicemia (meningococcemia) with or without meningitis Meningoencephalitis Pneumonia Arthritis Urethritis Diseases Associated with Neisseria meningitidis

Symptoms: Fever Rigors Headache Neck stiffness Photophobia Confused and seizures

Signs: Signs: Non-blanching purpuric rash Non-blanching purpuric rash Kernigs and Brudzinskis sign Kernigs and Brudzinskis sign

Meningococcal septicaemia purpuric rash Meningococcal septicaemia typically causes a purpuric rash, that does not lose its color when pressed with a glass ("non-blanching") and does not cause the classical symptoms of meningitis. This means the condition may be ignored by those not aware of the significance of the rash. Septicaemia carries an approximate 50% mortality rate over a few hours from initial onset. purpuric mortality rate

Diagnosis A small amount of cerebrospinal fluid (CSF) is sent to the laboratory as soon as possible for analysis. The diagnosis is suspected, whengram negative diplococci are seen on Gram stain of a centrifuged sample of CSF; sometimes they are located inside white blood cells. The microscopic identification takes around 1–2 hours after specimen arrival in the laboratorycerebrospinal fluidgram negativeGram stainwhite blood cells

The gold standard of diagnosis is microbiological isolation of N. meningitidis by growth from a sterile body fluid, which could be CSF or blood.gold standard Diagnosis is confirmed when the organism has grown, most often on a chocolate agar plate, but also on Thayer- Martin agar.chocolate agarThayer- Martin agar

Treatment Third-generation cephalosporin antibiotics (i.e. cefotaxime, ceftriaxone) should be used to treat a suspected or culture-proven meningococcal infection before antibiotic susceptibility results are available.cephalosporincefotaximeceftriaxone Antibiotic treatment may affect the results of microbiology tests, but a diagnosis may be made on the basis of blood-cultures and clinical examination.

Vaccination As of 2008 three vaccines have been available in the U.S. to prevent meningococcal disease for people aged 2 or older. All three vaccines are effective against the same serogroups: A, C, Y, and W-135. A meningococcal polysaccharide vaccine (MPSV4) has been available since the 1970s and is the only meningococcal vaccine licensed for people older than 55. MPSV4 may be used in people 2–55 years old if the MCV4 vaccines are not available or contraindicated. Two meningococcal conjugate vaccines (MCV4) are licensed for use in the U.S. The first conjugate vaccine was licensed in 2005, the second in Conjugate vaccines are the preferred vaccine for people 2 through 55 years of age. It is indicated in those with impaired immunity, such as nephrotic syndrome or splenectomy.The Centers for Disease Control and Prevention (CDC) publishes information about who should receive meningococcal vaccine. [23]conjugate vaccinesnephrotic syndromesplenectomyCenters for Disease Control and Prevention [23] In June 2012, the U.S. Food and Drug Administration (FDA) approved a combination vaccine against two types of meningococcal diseases and Hib disease for infants and children 6 weeks to 18 months old. The vaccine, Menhibrix, was designed to prevent disease caused by Neisseria meningitidis serogroups C and Y, and Haemophilus influenzaetype b (Hib). It was the first meningococcal vaccine that could be given to infants as young as six weeks old.Food and Drug AdministrationHibMenhibrix