Meningococcal Infection

Meningococcal infection is a serious and potentially fatal infection disease caused by the bacterium Neisseria meningitidis. This bacterium can naturally reside in the nasopharynx (nose and throat) of humans and is contagious. Meningococcal infection can lead to severe clinical presentations including meningitis (brain inflammation of the meninges) and meningococcemia (blood bloodstream infection). Disease poses a significant threat especially to infants adolescents and individuals with weakened immune systems. Meningococcal infection is characterized by abrupt onset symptoms and requires urgent medical intervention.

Etiology of Meningococcal Infection

The causative agent of meningococcal infection is a gram-negative bacterium known as Neisseria meningitidis which has a diplococcal (pair of spherical) shape. This bacterium is classified into different serogroups based on its capsule structure. The serogroups most commonly responsible for human infections are A B C W X and Y.

Characteristics of Neisseria meningitidis

• Structure: Gram-negative diplococcal morphology.
• Capsule: Protects the bacterium from the host immune system.
• Serogroups: A B C W X and Y.
• Transmission: Spreads from person to person via respiratory secretions.

Transmission Routes of Meningococcal Infection

Respiratory Transmission

• Coughing and sneezing
• Close contact (kissing sharing personal items)

Transmission in Crowded Settings

• Dormitories military barracks
• Schools daycares

Clinical Manifestations of Meningococcal Infection

Meningococcal infection primarily presents in two clinical forms: meningococcemia and meningococcal meningitis.

Meningococcemia

• High fever
• Petechial rash
• Hypotension
• Extremity ischemia

Meningococcal Meningitis

• Severe headache
• Neck stiffness
• Photophobia
• Altered mental status

Diagnosis of Meningococcal Infection

Blood Culture

• Directly detects the bacterium.

Cerebrospinal Fluid (CSF) Analysis

• Typical findings include increased white blood cell count and low glucose levels.

Molecular Diagnostic Methods

• Neisseria meningitidis DNA is detected using PCR.

Treatment of Meningococcal Infection

Antibiotic Therapy

• Penicillin: First-line choice.
• Cephalosporins: Cefotaxime or ceftriaxone.
• Chloramphenicol: Alternative in cases of allergy.

Supportive Therapy

• Fluid resuscitation
• Vasopressors (in cases of shock)

Prevention of Meningococcal Infection

Vaccination

• Conjugate vaccines (A C W Y)
• B serogroup vaccines

Hygienic Measures

• Hand hygiene
• Covering the mouth during coughing or sneezing

Prophylactic Treatment for Close Contacts

• Protection with rifampin or ciprofloxacin