Micro bacteria 3

Neisseria genus

• Contains two important human pathogens: Neisseria meningitidis and Neisseria gonorrhoeae
• N. meningitidis primarily causes meningitis and meningococcemia, the leading cause of infectious death in US children.
• N. gonorrhoeae causes gonorrhea, the second most common notifiable bacterial disease in the US.
• N. gonorrhoeae also causes neonatal conjunctivitis and pelvic inflammatory disease.

Properties of Neisseria

• Gram-negative cocci.
• Aerobic, performing oxidative metabolism.
• Lack flagella and spores.
• Possess capsules and pili.
• Require enriched complex media and CO2 for growth.
• Diplococci with a flattened or concave shape resembling paired kidney beans.
• Strict parasites, unable to survive long outside the host.
• Size ranges from 0.6–0.8 μm.
• Oxidase-positive, catalase-positive, and non-acid-fast.

Virulence Factors of Neisseria

• N. meningitidis (meningococcus)
  • Prominent polysaccharide capsule enhances virulence by inhibiting phagocytosis and stimulating protective antibody production.
  • Classified into at least 13 serogroups based on capsular polysaccharide antigenicity.
  • Five serotypes (A, B, C, Y, and W) cause most cases of meningitis and meningococcemia.
  • Serotype A is the main cause of epidemic meningitis globally.
  • Serotype B causes most cases in the US.
  • Capsule antigens are used for vaccine development.
• N. gonorrhoeae (gonococcus)
  • Lacks a polysaccharide capsule.
  • Multiple serotypes based on pilus protein antigenicity.
  • Marked antigenic variation in pili arises from chromosomal rearrangements, resulting in over 100 known serotypes.
  • Three outer membrane proteins (I, II, and III).
  • Protein II aids in attachment to cells and exhibits antigenic variation.

Properties of Neisseria Endotoxin

• Neisseria are gram-negative bacteria, containing endotoxin in their outer membrane.
• Neisseria's endotoxin consists of lipooligosaccharide (LOS), unlike the lipopolysaccharide (LPS) found in enteric gram-negative rods.
• Both LOS and LPS contain lipid A, but LOS contains few sugars in its oligosaccharide part, while LPS has a long repeating sugar side chain.

Neisseria Growth Requirements

• Both N. meningitidis and N. gonorrhoeae growth are inhibited by toxic trace metals and fatty acids found in certain culture media.
• They are cultured on "chocolate" agar, containing blood heated to 80°C, which inactivates the inhibitors.
• Neisseria are oxidase-positive, possessing the enzyme cytochrome c.

Neisseria

• Consists of two major human pathogens: Neisseria meningitidis and Neisseria gonorrhoeae
• N. meningitidis primarily causes meningitis and meningococcemia.
• N. gonorrhoeae causes gonorrhea, neonatal conjunctivitis, and pelvic inflammatory disease.

Clinical Features of Neisseria

• N. meningitidis infection can lead to meningococcemia, where bacteria enter the bloodstream and multiply, causing damage to blood vessel walls.
• N. meningitidis is the leading cause of death from infection in children in the United States.

Important Properties of Neisseria

• Gram-negative cocci
• Aerobic
• Lack flagella and spores
• Capsulated with pili
• Require enriched, complex media and CO2 for growth.
• Diplococcus with flattened or concave shape resembling paired kidney beans.
• Strict parasites that cannot survive long outside of the host.
• Size ranges between 0.6–0.8 μm
• Oxidase-positive
• Non-acid-fast
• Produce catalase and oxidase

Important Properties and Virulence Factors of Neisseria

• 1. N. meningitidis (Meningococcus)*

• Has a prominent polysaccharide capsule crucial for enhancing virulence.

• The capsule inhibits phagocytosis and triggers protective antibody production.

• Classified into at least 13 serologic groups based on their capsular polysaccharide antigens.

• Five serotypes (A, B, C, Y, and W) cause most cases of meningitis and meningococcemia.

• Serotype A dominates epidemics worldwide.

• Serotype B is the most common cause in the United States.

• Capsule antigens are used in the formulation and manufacture of vaccines.

• 2. N. gonorrhoeae (Gonococcus)*

• Lacks a polysaccharide capsule

• Classified into multiple serotypes based on the antigenicity of its pilus protein.

• Exhibits significant antigenic variation in pili due to chromosomal rearrangements.

• Over 100 serotypes are known.

• Has three outer membrane proteins (I, II, and III).

• Protein II plays a role in attachment and displays antigenic variation.

Antigenic Properties

• Neisseria species are gram-negative bacteria.
• Their outer membranes contain endotoxin (Lipooligosaccharide, LOS).
• LOS differs from the lipopolysaccharide (LPS) found in enteric gram-negative rods.
• Both LOS and LPS contain lipid A, but LOS has few sugars in its oligosaccharide portion, whereas LPS contains a long repeating sugar side chain.

Growth and Detection

• The growth of both N. meningitidis and N. gonorrhoeae is inhibited by toxic trace metals and fatty acids present in certain culture media (e.g., blood agar plates).
• They are cultured on "chocolate" agar, which contains blood heated to 80°C to inactivate the inhibitors.
• Neisseriae are oxidase-positive, meaning they contain the enzyme cytochrome c.

Neisseria

• The genus Neisseria contains two important human pathogens: Neisseria meningitidis and Neisseria gonorrhoeae.
• Neisseria meningitidis is commonly known as the meningococcus.
• Neisseria gonorrhoeae is commonly known as the gonococcus.
• N. meningitidis mainly causes meningitis and meningococcemia.
• Meningococcemia is when bacteria enter the bloodstream, multiply, and damage blood vessel walls.
• N. gonorrhoeae causes gonorrhea, the second most common notifiable bacterial disease in the United States.
• N.gonorrhoeae causes neonatal conjunctivitis, also known as ophthalmia neonatorum.
• N. gonorrhoeae also causes pelvic inflammatory disease (PID).

Important Properties of Neisseria

• Neisseria spp. are Gram-negative cocci.
• They are aerobic and utilize oxidative metabolism.
• They do not possess flagella or spores.
• They are capsulated and possess pili.
• They require enriched, complex media and carbon dioxide for growth.
• They are diplococci with a flattened or concave shape, resembling paired kidney beans within neutrophils.
• They are strict parasites, unable to survive long outside the host.
• They are oxidase-positive and produce catalase.
• Their size ranges between 0.6–0.8 μm.

Virulence Factors

• N. meningitidis has a prominent polysaccharide capsule, enhancing virulence by its antiphagocytic action and inducing protective antibodies.
• N. meningitidis is divided into at least 13 serologic groups based on the antigenicity of their capsular polysaccharides.
• Five serotypes cause most cases of meningitis and meningococcemia: A, B, C, Y, and W.
• Serotype A is the leading cause of epidemic meningitis worldwide.
• Serotype B accounts for most diseases in the United States.
• Capsule antigens are used in vaccine formulation and manufacture.
• N. gonorrhoeae does not have a polysaccharide capsule.
• N. gonorrhoeae has multiple serotypes based on the antigenicity of its pilus protein.
• The gonococcal pili have marked antigenic variation due to chromosomal rearrangement.
• More than 100 serotypes of N. gonorrhoeae are known.
• N. gonorrhoeae has three outer membrane proteins (proteins I, II, and III).
• Protein II plays a role in attaching the organism to cells and also varies antigenically.

Antigenic Properties

• Neisseriae are gram-negative bacteria containing endotoxin in their outer membrane.
• The endotoxin of Neisseriae consists of lipo-oligosaccharide (LOS), unlike the lipopolysaccharide (LPS) found in enteric gram-negative rods.
• Both LPS and LOS contain lipid A, but LOS contains few sugars in its oligosaccharide part, while LPS contains a long repeating sugar side chain.

Culture

• The growth of both N. meningitidis and N. gonorrhoeae is inhibited by toxic trace metals and fatty acids found in certain culture media (e.g., blood agar plates).
• They are cultured on "chocolate" agar containing blood heated to 80°C, which inactivates the inhibitors.
• Neisseriae are oxidase-positive, possessing the enzyme cytochrome c.

Neisseria Genus

• Contains two important human pathogens: Neisseria meningitidis and Neisseria gonorrhoeae.
• N. meningitidis primarily causes meningitis and meningococcemia.
• N. gonorrhoeae is the causative agent of gonorrhea, the second most common notifiable bacterial disease in the United States.
• N. gonorrhoeae also causes neonatal conjunctivitis (ophthalmia neonatorum) and pelvic inflammatory disease (PID).
• N. meningitidis is also known as the meningococcus, and N. gonorrhoeae is also known as the gonococcus.

Important Properties of Neisseria

• Gram-negative cocci.
• Aerobic (Oxidative metabolism).
• Do not possess flagella or spores.
• Capsulated and possess pili.
• Require enriched complex media and CO2.
• Diplococcus, resembling paired kidney beans within neutrophils.
• Strict parasites, unable to survive long outside the host.
• Size ranges between 0.6–0.8 μm.
• Oxidase-positive, non-acid-fast cocci.
• Produce catalase and oxidase.

Virulence Factors of Neisseria

• N. meningitidis (meningococcus)

  • Possesses a prominent polysaccharide capsule enhancing virulence by its antiphagocytic action and inducing protective antibodies.
  • Divided into at least 13 serologic groups based on capsular polysaccharide antigenicity.
  • Five serotypes (A, B, C, Y, and W) cause most cases of meningitis and meningococcemia.
  • Serotype A is the leading cause of epidemic meningitis worldwide.
  • Serotype B accounts for most diseases in the United States.
  • Capsule antigens are utilized in vaccine formulation.

• N. gonorrhoeae (gonococcus)

  • Lacks a polysaccharide capsule.
  • Has multiple serotypes based on the antigenicity of its pilus protein.
  • Marked antigenic variation in the gonococcal pili due to chromosomal rearrangement.
  • Over 100 serotypes are known.
  • Possesses three outer membrane proteins (proteins I, II, and III).
  • Protein II is involved in attachment to cells and exhibits antigenic variation.

Antigenic Properties of Neisseria

• Gram-negative bacteria containing endotoxin in their outer membrane.
• Neisseriae endotoxin consists of lipo-oligosaccharide (LOS), distinct from the lipopolysaccharide (LPS) found in enteric gram-negative rods.
• Both LPS and LOS contain lipid A, but LOS has a shorter oligosaccharide component compared to the long repeating sugar side chain of LPS.

Culture and Growth of Neisseria

• The growth of both N. meningitidis and N. gonorrhoeae is inhibited by toxic trace metals and fatty acids found in certain culture media.
• They are cultured on "chocolate" agar containing blood heated to 80°C, which inactivates these inhibitors.
• Neisseriae are oxidase-positive, possessing the enzyme cytochrome c.

Neisseria: The Genus

• Neisseria includes two important human pathogens: Neisseria meningitidis and Neisseria gonorrhoeae.
• N. meningitidis is a leading cause of death from infection in children in the United States.
• N. gonorrhoeae causes gonorrhea, the second most common notifiable bacterial disease in the United States.

Clinical Features of Neisseria

• N. meningitidis primarily causes meningitis and meningococcemia, which is when the bacteria enter the bloodstream and multiply, damaging blood vessel walls.
• N. gonorrhoeae can cause:
  • Gonorrhea
  • Neonatal conjunctivitis (ophthalmia neonatorum)
  • Pelvic inflammatory disease (PID).

Important Properties of Neisseria

• Gram-negative cocci
• Aerobic (oxidative metabolism)
• No flagella or spores
• Capsulated and possess pili
• Require enriched complex media and CO2
• Diplococci that appear flattened or concave (resembling kidney beans)
• Strict parasites, can't survive long outside of the host
• Size ranges between 0.6–0.8 μm
• Oxidase-positive
• Non-acid-fast
• Produce catalase and oxidase

Virulence Factors of Neisseria

N. meningitidis

• Possesses a prominent polysaccharide capsule that increases virulence through antiphagocytic action and induces protective antibody responses.
• This capsule is responsible for differentiating meningococci into at least 13 serologic groups.
• Five serotypes cause the majority of cases: A, B, C, Y, and W.
  • Serotype A is the leading cause of epidemic meningitis worldwide.
  • Serotype B is the most prevalent in the United States.

N. gonorrhoeae

• Lacks a polysaccharide capsule but has multiple serotypes based on pilus protein antigenicity.
• Has three outer membrane proteins (proteins I, II, and III) that play a role in attachment to cells.
• Protein II varies antigenically.

Antigenic Properties

• Neisseria species contain endotoxin in their outer membrane.
• The endotoxin is known as lipooligosaccharide (LOS) in Neisseria, unlike the lipopolysaccharide (LPS) found in enteric gram-negative bacteria.
• Both LOS and LPS contain lipid A, but LOS has a shorter oligosaccharide portion with fewer sugars compared to the longer, repeating sugar side chain of LPS.

Growth Requirements

• Both N. meningitidis and N. gonorrhoeae growth is inhibited by toxic trace metals and fatty acids found in certain culture media.
• Therefore, they are cultured on "chocolate" agar, which is blood heated to 80 °C to inactivate inhibitors.
• Neisseria are oxidase-positive.