Neisseriaceae spp.

• Gram + cocci

  • Staphylococcus spp.
  • Micrococcus spp. [Catalase Positive]
  • Streptococcus spp.
  • Enterococcus spp. [Catalase Negative]
• First Test: Catalase


  To differentiate Gram + cocci
• Gram + diplococci

  Streptococcus pneumoniae
• Streptococcus pneumoniae


  • No C carbohydrate
  • Merong C substance
  • Autolytic enzyme [like S. aureus]
• Gram - diplococci


  • Neisseria spp.
  • Moraxella spp.
• First Test: Oxidase Test (+)


  To differentiate Gram - diplococci
• Gram - bacilli

  • Vibrio spp.
  • Aeromonas spp.
  • Pleisiomonas spp.
  • Campylobacter spp.
  • Helicobacter spp.
• First Test: Oxidase Test (+)


  To differentiate Gram - bacilli
• Family Neisseriaceae

  • Other members are oxidase positive, but catalase negative [like Edwarsiella spp.]
• Neisseria

  • Aerobic, nonmotile, non-spore-forming, gram-negative diplococci except: Neisseria elongata, Neisseria weaeri, and Neisseria bacciliformis
  • Kidney-bean shaped
  • All are cytochrome oxidase and catalase positive except for N. elongata and N. bacilliformis [catalase negative]
  • Capnophilic; can grow anaerobically if alternative electron acceptors (e.g., nitrites) are available
  • Normal inhabitants of the human respiratory tract except Neisseria gonorrhoeae and Neisseria animaloris [leading to infection; pathogenic]
  • Pathogenic for humans and are found associated inside polymorphonuclear cells
• Neisseria gonorrhoeae and Neisseria meningitidis


  • Require iron for growth [fastidious]
  • Receptor for transferrin [transport protein for iron]
  • Compete with RBCs for the presence of iron in our body
• Transmission of Neisseria

  1. N. gonorrhoeae: sexually transmitted

  2. N. meningitidis: respiratory droplets
• Virulence Factors of Neisseria

  • Receptors for human transferrin
  • Capsulated – N. meningitidis
  • Pili (fimbriae)
  • T1 and T2: virulent forms [have pili and fimbriae]
  • T3 through T5: avirulent [no pili, no fimbriae]
  • Protein 1 (Por): forms channels for nutrients to pass into and waste products to exit the cell
  • Protein II (Opa): facilitate the adherence to phagocytic and epithelial cells
  • Protein III (reduction modified protein [Rmp]): blocks the bactericidal effect of host IgG
  • Lipooligosaccharide (LOS) or endotoxin
  • Immunoglobulin A (IgA) protease that cleaves IgA on mucosal surfaces
  • Lip (H8): a surface exposed protein that is heat modifiable like Opa
  • Fbp (ferric-binding protein): expressed when the available iron supply is limited
• Neisseria gonorrhoeae


  • Oxidize only glucose [in CHO utilization test]
  • Require arginine, hypoxanthine, and uracil
  • Agent of the sexually transmitted disease gonorrhea
  • Not part of normal microbiota
  • Only found on mucous membranes of genitalia, anorectal area, oropharynx, or conjunctiva at time of infection
  • Aerobic and capnophilic
• In terms of carbohydrate utilization test, N. gonorrhoeae can only oxidize glucose.
• Neisseria gonorrhoeae AHU strain


  • Require Arginine, Hypoxanthine, and uracil
  • Found in asymptomatic male; urethra
• Gonorrhea


  • Acute pyogenic infection of non-ciliated columnar and transitional epithelium
  • Acquired through sexual contact
  • Occur primarily in the urethra, endocervix, anal canal, pharynx, and conjunctiva
  • Incubation Period: 2-7 days
• Clinical Manifestation of Neisseria gonorrhoeae

  • Men: acute urethritis and dysuria. Asymptomatic is uncommon (3-5% asymptomatic)
  • Women: dysuria, cervical discharge, and lower abdominal pain, 50%-Asymptomatic
  • Pelvic inflammatory disease – women
  • Anorectal and oropharyngeal infections
  • Newborns: ophthalmia neonatorum – gonococcal eye infection
• Specimen Collection and Transport of Neisseria gonorrhoeae

  • Pus and secretions are taken from the urethra, cervix, rectum, conjunctiva, throat, or synovial fluid for culture and smear
  • Specimen of Choice: Men - urethra, Women - endocervix
  • Swabs: Dacron or rayon swabs – preferred
  • Cotton swabs are toxic for neisseria [contains excessive fatty acids]
  • Direct Plating: James E. Martin Biological Environmental Chamber (JEMBEC) plates, Gono-Pak and Transgrow – BRAND NAMES
  • Medium of Choice: Chocolate Agar Plate
  • Amies Medium with charcoal [in case of unavailability of specific transport systems]
  • Within 6 hours, it should be plated already
• Direct Microscopic Examination of Neisseria gonorrhoeae

  • Urogenital specimens: gram-negative intracellular diplococci
  • In pairs with adjacent sides flattened, kidney shaped
  • Gram stain: not recommended for pharyngeal specimens
  • More than five polymorphonuclear neutrophils per field but no bacteria: nongonococcal urethritis with other organisms, such as C. trachomatis or Ureaplasma urealyticum
• Culture of Neisseria gonorrhoeae

  • Medium of Choice: CHOC Agar
  • Trypticase soy agar with 5% sheep blood
  • Not growing on sheep blood agar (SBA) = blood agar plate (BAP)
• Incubation of Neisseria gonorrhoeae

  • 35°C in a 3% to 5% CO2 atmosphere
  • Use of a CO2 generating pouch, or a candle extinction jar (increase CO2)
  • Cultures are examined daily for growth and held for 72 hours
• Colonial Appearance of Neisseria gonorrhoeae

  • Small grayish white, convex, translucent, shiny colonies with either smooth or irregular margins
  • Staph – opaque
  • Strep – transparent
  • Neisseria – translucent
• Microscopic Morphology of Neisseria gonorrhoeae: Gram-negative diplococci
• Definitive Identification of Neisseria gonorrhoeae

  • Oxidase Test
  • Carbohydrate Utilization
  • Chromogenic Substrates
  • Multitest Methods
  • Immunologic Assays
  • Matrix-Assieted Laser Desorption/Ionization-Time-of-flight Mass Spectrometry (MALDI-TOF MS)
  • Nucleic Acid Amplification Tests (NAAT)
• Biochemical tests

  • Ate tests with other biochemical tests
  • Allow for identification of strains isolated on selective for nonselective media
  • Immunologic assays
• Immunologic assays


  • Co-agglutination and fluorescent antibody testing
  • Monoclonal antibodies against gonococcal protein I
  • Do not require pure or viable organisms
  • N. gonorrhoeae attached to killed Staphylococcus aureus cells
  • No need for pure culture
  • Positive: Agglutination
• MALDI-TOF MS


  • Most advanced equipment for the identification of bacteria
  • Identifies infectious pathogens by defining unique protein signatures of the organism
  • Popular
  • Principle: The colony is ionized to vaporization of proteins, the proteins separate based on size and charge resulting to unique spectral signature and compared to the identified pathogen
• Nucleic Acid Amplification Tests (NAAT)


  • Amplify a specific nucleic acid sequence before detecting the target sequence with a probe
  • Increased sensitivity
  • Specificity
  • Ability to test with a noninvasive urine specimen
• Penicillin resistance in Neisseria gonorrhoeae

  • Plasmid-mediated penicillin resistance: penicillinase- producing Neisseria gonorrhoeae (PPNG)
  • Chromosome-mediated penicillin resistance (PenR) – Beta – lactamase negative
• Treatment of Neisseria gonorrhoeae

  • Ceftriaxone (Cephalosporin)
  • Ceftriaxone plus azithromycin – co-infection with C. trachomatis
• Neisseria meningitidis


  • Commensal as well as an invasive pathogen
  • Important etiologic agent of endemic and epidemic meningitis and meningococcemia and rarely pneumonia, purulent arthritis, or endophthalmitis
  • Mode of transmission: close contact with respiratory droplet secretions
  • Serogroups A,B,C,Y and W-135: account for most cases of disease in the world
  • Capsule: sialic acid moieties
  • Incubation period: 1-10 days
  • After incubation, there are none or mild manifestation
  • But in some cases, there could be manifestation of meningitis or sepsis
• Fulminant meningococcemia


  • Purpura with petechial skin
  • Tachycardia
  • Hypotension
  • Thrombosis (concurrent blood clots)
  • Intravascular coagulation
  • Septic shock
  • Hemorrhage in the adrenal glands (Waterhouse- Friedrichsen syndrome)
• Meningitis


  • Characterized by an abrupt onset of front headache, stiff neck (nuchal rigidity), confusion, and photophobia
• Specimen collection and transport for Neisseria meningitidis

  • Cerebrospinal fluid (CSF), blood, nasopharyngeal swabs and aspirates, joint fluids, and, less commonly, sputum and material from urogenital sites
  • Inhibited by SPS [anti-coagulant; 0.035% sodium polyanethole sulfonate], when commercial blood culture systems are used, you need to add gelatin to neutralize the effect
• Direct microscopic examination of Neisseria meningitidis

  Intracellular and extracellular gram-negative diplococci
• Culture and incubation of Neisseria meningitidis

  • SBA and CHOC agar
  • Same atmospheric conditions described for N. gonorrhoeae
  • Examined daily for 72 hours
• Colonial appearance of Neisseria meningitidis


  Medium, smooth, round, moist, gray to white; encapsulated [mucoid colony] strains are mucoid; may be greenish cast in agar underneath colonies
• Identification of Neisseria meningitidis


  • Oxidase Positive (+) & Coagulase (+)
  • Carbohydrate methods – uses glucose and maltose
  • Molecular techniques
  • MALDI-TOF
• Treatment of Neisseria meningitidis

  • DOC: Penicillin
  • Do not develop resistance with penicillin
  • For Meningococcemia: third generation cephalosporins
  • Chemoprophylaxis: rifampin or ciprofloxacin
  • For ciprofloxacin resistance: azithromycin