Neisseria meningitides and Study of Epidemiology, Molecular Characteristics and Prevention of Meningococcal Infection

Neisseria meningitidis is an encapsulated, aerobic, Gram-negative diplococcal bacterium that is oxidase-positive. It grows on chocolate agar, soybean agar, and Mueller-Hinton agar. This organism causes meningitis, a serious bacterial disease characterized by fever, headache, nausea, neck and muscle pain. It is transmitted via airborne droplets originating from respiratory and throat secretions. Neisseria meningitidis colonizes the upper layers of the mucosal tissues in infected individuals, invades the bloodstream, and can lead to severe septicemia and meningitis. The bacterium is responsible for high mortality rates in children as well as adults worldwide. Despite the use of antibiotics, the current mortality rate remains around 10%. The phenotypic classification of Neisseria meningitidis includes twelve serogroups based on variations in surface structures such as the polysaccharide capsule, lipooligosaccharide, and outer membrane proteins. Among these twelve serogroups, five (A, B, C, W, Y) are the primary causes of disease and have contributed significantly to the global spread of meningococcal infections. The bacterial capsule plays a crucial role in inducing bactericidal antibodies, particularly those targeting the polysaccharide capsule, which is essential for vaccine development. An exception is the B-polysaccharide, which has low immunogenicity. The capsule has several functions: it protects against the host immune system by preventing phagocytosis, facilitates colonization of the nasopharynx, and protects the bacteria during bloodstream dissemination, enabling it to reach the meninges and cause meningitis. Furthermore, the capsule contributes to antibiotic resistance and is a key component in vaccines, particularly those containing polysaccharide or protein-conjugated polysaccharide formulations. Vaccination is considered one of the most effective preventive measures against meningococcal disease. Neisseria meningitidis also possesses two types of (cilia), which aid in adhesion to epithelial cells. Recent studies have identified genetic mutations that introduce new mechanisms for developing antibiotic resistance, such as mutations in the rpsJ and TetM genes. To enhance prevention strategies against meningococcal disease, a novel antigen named 4CMenB has been identified through serogroup analysis. A protein-polysaccharide conjugation approach was applied, leading to improved T-cell immunity and memory cell immune responses. Third-generation cephalosporins are commonly used for the treatment of drug-resistant strains. Objective: To summarize the molecular characteristics of Neisseria meningitidis, the causes of infection, preventive strategies, and its epidemiology.