Bacteriology Lecture: Neisseria Overview

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Questions and Answers

What is a characteristic of Neisseria weaveri?

  • It requires high levels of oxygen for growth.
  • It is primarily found in marine environments.
  • It is a fastidious organism. (correct)
  • It is a commensal in the upper respiratory tract of cats.

Which age group has the highest rates of gonorrhea infection?

  • Men and women ages 30 to 34
  • Men and women ages 15 to 19
  • Men and women ages 25 to 29
  • Men and women ages 20 to 24 (correct)

Why are Neisseria spp. considered opportunistic pathogens?

  • They thrive in marine environments.
  • They have a common reservoir in birds.
  • They are the only pathogens causing sexually transmitted infections.
  • They can cause infections when the host is immunocompromised. (correct)

What is required for the growth of fastidious organisms, such as those in the Neisseria genus?

<p>Iron (B)</p> Signup and view all the answers

What is true about gonorrhea as a national reportable disease?

<p>Confirmed cases must be reported to state health laboratories. (D)</p> Signup and view all the answers

What is the most common site of infection in women related to clinical infections?

<p>Endocervix (D)</p> Signup and view all the answers

Which of the following is NOT a symptom of clinical infections in women?

<p>Fever (C)</p> Signup and view all the answers

What type of swabs should NOT be used for collecting specimens for Neisseria gonorrhoeae?

<p>Calcium alginate swabs (C)</p> Signup and view all the answers

Which of the following complications can arise from pelvic inflammatory disease?

<p>Both A and B (A)</p> Signup and view all the answers

What is the proper depth for inserting a swab into the anal canal for a rectal culture?

<p>4 to 5 cm (C)</p> Signup and view all the answers

Which statement correctly describes the general characteristics of most Neisseria species?

<p>Most Neisseria species are aerobic and Gram-negative diplococci. (A)</p> Signup and view all the answers

Which virulence factor is specifically associated with Neisseria meningitidis?

<p>Capsule (D)</p> Signup and view all the answers

What is the primary natural habitat for pathogenic Neisseria species?

<p>Mucous membranes of respiratory and urogenital tracts (C)</p> Signup and view all the answers

Which of the following is NOT a primary site for Neisseria gonorrhoeae infection?

<p>Stomach (B)</p> Signup and view all the answers

Which characteristic distinguishes Neisseria gonorrhoeae in terms of its natural host?

<p>It is exclusively a human pathogen. (A)</p> Signup and view all the answers

What is the typical incubation period for gonococcal arthritis?

<p>2 to 7 days (C)</p> Signup and view all the answers

Which of the following is the most common cause of anal canal infections in men?

<p>Intimate sexual contact with men (A)</p> Signup and view all the answers

Which symptom is NOT commonly associated with acute gonococcal infection in men?

<p>Persistent cough (D)</p> Signup and view all the answers

What percentage of infected women may develop anorectal infections?

<p>30% to 60% (A)</p> Signup and view all the answers

What is the primary complication associated with untreated gonococcal infection in newborns?

<p>Blindness (D)</p> Signup and view all the answers

What preventive measure is recommended for newborns to avoid gonococcal infection?

<p>Application of eye drops (B)</p> Signup and view all the answers

Which statement about asymptomatic gonococcal infections in men is correct?

<p>It is uncommon in men. (D)</p> Signup and view all the answers

What is the common manifestation of acute gonococcal infection in men?

<p>Acute urethritis (B)</p> Signup and view all the answers

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Study Notes

Neisseria General Characteristics

  • Most Neisseria species are aerobic, non-motile, non-spore forming, and gram-negative diplococci.
  • Cytochrome oxidase positive and catalase negative (exceptions include N.elongate subsp., Nitroreducens, and N.bacilliformis).
  • Capnophilic; capable of anaerobic growth with nitrites as alternative electron acceptors.
  • Natural habitat includes mucous membranes of respiratory and urogenital tracts.
  • Primary human pathogens: Neisseria gonorrhoeae and Neisseria meningitidis.
  • Neisseria weaveri is a commensal organism found in dogs.

Pathogenic Neisseria spp. Virulence Factors

  • Possess receptors for human transferrin, allowing iron acquisition.
  • N. meningitidis has a capsule and pili (fimbriae) for adhesion.
  • Produce specific cell membrane proteins and lipooligosaccharide (LOS) which acts as an endotoxin.
  • Immunoglobulin A (IgA) protease cleaves IgA on mucosal surfaces.

Neisseria gonorrhoeae Overview

  • Exclusive natural host is humans and the primary agent of gonorrhea.
  • Infection sites: urethra, endocervix, anal canal, pharynx, and conjunctiva.

Epidemiology

  • Transmitted primarily through sexual contact; asymptomatic carriers serve as the main reservoir.
  • Confirmed cases of gonorrhea are reportable to state health authorities.
  • Highest infection rates among individuals aged 20 to 24.
  • Gonorrhea ranks second to Chlamydia trachomatis in sexually transmitted bacterial infections in the US.

Clinical Infections

  • Incubation Period: Approximately 2 to 7 days.
  • Gonorrhea Symptoms:
    • Acute pyogenic infections typically in the urogenital tract, pharynx, and conjunctiva.
    • Complications include disseminated infections and anorectal infections; 30% to 60% of women with genital infection may develop anorectal infections.

Clinical Infections in Men

  • Transmission: Occurs through intimate sexual contact, with 90% showing symptoms.
  • Common Symptoms: Acute urethritis and dysuria; asymptomatic cases are uncommon.
  • Complications: Prostatitis, urethral stricture, and epididymitis can arise from untreated infections.

Clinical Infections in Women

  • Common Infection Site: Endocervix, often presenting with dysuria and cervical discharge.
  • Symptoms may include lower abdominal pain; 50% are asymptomatic.
  • Potential complications include pelvic inflammatory disease, sterility, and ectopic pregnancy.

Disease in Newborns

  • Ophthalmia neonatorum can occur if an infant is born through an infected canal, risking blindness without immediate treatment.
  • Erythromycin eye drops are used for prevention at birth to protect against infection.

Specimen Collection and Transport

  • Preferred specimen sites include rectal, oral/pharyngeal, eye, and blood/joint fluids.
  • Recommended swabs for collection are Dacron or rayon; avoid calcium alginate and cotton swabs as they inhibit N. gonorrhoeae.
  • Direct plating of specimens on gonococcal-selective media is optimal for culture.

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