What is the immune response to Neisseria meningitidis?
Abstract. Neisseria meningitidis (Nme) can cause meningitis and sepsis, diseases which are characterised by an overwhelming inflammatory response. Inflammation is triggered by host pattern recognition receptors (PRRs) which are activated by pathogen-associated molecular patterns (PAMPs).
How does the body fight Neisseria meningitidis?
The bacterium is only found in human hosts, and so must continually coexist with the immune system. Consequently, N meningitidis uses multiple mechanisms to avoid being killed by antimicrobial proteins, phagocytes, and, crucially, the complement system.
What does Neisseria meningitidis look like under a microscope?
Neisseria meningitidis is a Gram-negative, non-spore forming, non-motile, encapsulated, and non-acid-fast diplococci, which appears in kidney bean shape under the microscope.
How does the body respond to bacterial meningitis?
Meningitis is an infection of the membranes (meninges) that protect the spinal cord and brain. When the membranes become infected, they swell and press on the spinal cord or brain. This can cause life-threatening problems. Meningitis symptoms strike suddenly and worsen quickly.
What is the pathogenesis of Neisseria meningitidis?
Neisseria meningitidis is a harmless commensal bacterium finely adapted to humans. Unfortunately, under “privileged” conditions, it adopts a “devious” lifestyle leading to uncontrolled behavior characterized by the unleashing of molecular weapons causing potentially lethal disease such as sepsis and acute meningitis.
What does Neisseria meningitidis look like?
meningitidis are grey and unpigmented on a BAP and appear round, smooth, moist, glistening, and convex, with a clearly defined edge. N. meningitidis appear as large, colorless-to-grey, opaque colonies on a CAP.
What is the structure of Neisseria meningitidis?
Cell Envelope. In gram-negative bacteria, such as N. meningitidis, the subcapsular cell envelope consists of an outer membrane (OM), a peptidoglycan layer, and a cytoplasmic or inner membrane (Fig. 1).
How does Neisseria meningitidis cause meningitis?
Meningococcal meningitis evolves when the bacteria, Neisseria meningitidis (N. meningitidis) progresses from initial adherence to the nasopharyngeal (nose and throat) mucosa to invasion of the deeper mucosal layers (the submucosa). These bacteria rapidly multiply, and can lead to a mild (subclinical) infection.
What is the pathophysiology of meningitis?
The pathogenesis and pathophysiology of bacterial meningitis involve a complex interplay between virulence factors of the pathogens and the host immune response [3,4]. Much of the damage from this infection is believed to result from cytokines released within the CSF as the host mounts an inflammatory response.
Is Neisseria meningitidis beta hemolytic?
Neisseria meningitidis They are non-haemolytic on blood agar plate and do not reduce nitrates.
How does Neisseria meningitidis infect cells?
Neisseria meningitidis, a common cause of sepsis and bacterial meningitis, infects the meninges and central nervous system (CNS), primarily via paracellular traversal across the blood-brain barrier (BBB) or blood-cerebrospinal fluid barrier.
What are the virulence factors of Neisseria meningitidis?
The virulence (14) of N. meningitidis is influenced by multiple factors: capsule polysaccharide expression, expression of surface adhesive proteins (outer membrane proteins including pili, porins PorA and B, adhesion molecules Opa and Opc), iron sequestration mechanisms, and endotoxin (lipooligosaccharide, LOS).
How does Neisseria meningitidis attach to cells?
Neisseria meningitidis adheres to brain microvascular endothelial cells by the interaction of Type IV pili with an unknown adhesion receptor.
How does meningitis enter the blood brain barrier?
In order to cause meningitis, bacterial pathogens must survive in the bloodstream and penetrate or transmigrate across the blood–brain barrier (BBB), which is primarily comprised of a single layer of specialized endothelial cells.
What type of hemolysis is Neisseria meningitidis?
Neisseria meningitidis grows on them without hemolysis. Colonies of Neisseria meningitidis are unpigmented and appear round, smooth, glistening, and convex, with a clearly defined edge. Some strains may produce larger, grey, opaque colonies.
How does Neisseria meningitidis infect the host?
The initial interaction between the meningococcus and the host cell is mediated through the meningococcal type IV pilus. The meningococcus then retracts the pilus bringing the bacterium into close contact with the host cell surface [17].