Neisseria gonorrhoeae : Basics

Neisseria gonorrhoeae :Basics

Q. 1

Which of the following is not true about Neisseria gonorrhoeae ‑

 A It is an exclusive human pathogen
 B Some strains may cause disseminated disease
 C Acute urethritis is the most common manifestation in males
 D All strains are highly sensitive to penicillin
Q. 1

Which of the following is not true about Neisseria gonorrhoeae ‑

 A It is an exclusive human pathogen
 B Some strains may cause disseminated disease
 C Acute urethritis is the most common manifestation in males
 D All strains are highly sensitive to penicillin
Ans. D

Explanation:

All strains are highly sensitive to penicillin [Ref : Anantnarayan 8th/e p. 227-228; Harrison 17th/e p. 916-918; Jawetz 23″1/e p. 300]

  • Gonorrhoea is a gram negative organism.
  • The genus Neisseria contains two important human pathogens

N. gonorrhoea

– N. meningitides

  • Neisseria gonorrhoea causes gonorrhoea and Neisseria meningitides causes meningitis.
  • Neisseria gonorrhoea infections have a high prevalence and low mortality where as N. meningitides infections have low prevalence and high mortality.
  • Many Neisseria species are a part of normal flora in humans and animals.
  • Neisseria meningitides .frequently occurs in a carrier state in the absence of any disease.
  • However, Neisseria Gonorrhoea is an “obligate pathogen” and is never part of the normal human flora under any circumstances.

Gonococci is exclusive to humans

  • Gonorrhoea is an exclusive human disease, there being no natural infection in animals.
  • The only source of infection is a human carrier or less often a patient. In women gonococcus usually cause asymptomatic infection wheras in men the infection is usually symptomatic.

Clinical features of Gonococcal infection:-

  • Neisseria Gonorrhoea infection is acquired by sexual contacts and usually affects the mucous membrane of the urethra in males and endocervix and urethra in females.
  • They mainly affect the host’s columnar or cuboidal epithelium.

The vaginal mucosa is usually not affected in the adults because the stratified squamous epithelium is resistant to infection by the cocci and also because of the acid pH of vaginal secretions.

Clinical disease as a rule is less severe in females.

In women gonococcus usually cause “asymptomatic infection” the existence of asymptomatic carriage in women makes them a reservoir serving to perpetuate infection among their male contacts.

Gonococcal infection in men is usually “symptomatic”.
In men the disease starts as an acute urethritis.

PID

1f gonococcal infections

are asymptomatic or

unrecognized may

progress to P.1.D.

Fitz — Hugh Curtis syndrome

– Occurs due to direct

extension of the

organism through

fallopian tube to liver

Treatment of Gonorrhoea 😕

  • “Penicillin is ineffective in treatment of Gonorrhoea as most of the strains are resistant to penicillin because penicillinase producing N. gonorrhoea have spread widely”.

Neisseria Gonorrhoea has become resistant to numerous antibiotics because 😕

a)  It has got remarkable capacity to alter its antigenic structure.

b)  It can easily adopt to changes in microenvironment.

“Now the treatment of choice for gonococcal infection is ceftriaxone”.

  • “Quinolones” are the drug of choice for penicillin allergy.
  • In Patients who cannot tolerate both cephalosporin and quinolones, spectinomycin is the D.O.C.

Gonococcal infection: DOC

•  D.O.C.

-Ceftriaxonc

•  D.O.C. for penicillin allergey

-*Quinolones

•  If cannot tolerate both cephalosporins

and Quinolones

—4 Spectinomycin


Q. 2 Gonorrhea is assumed to be caused by gonococcus. Gonococcus can be identified by being:
 A By the growth on McConkey medium
 B By the fermentation of maltose
 C By the fermentation of glucose
 D Gram positive
Q. 2 Gonorrhea is assumed to be caused by gonococcus. Gonococcus can be identified by being:
 A By the growth on McConkey medium
 B By the fermentation of maltose
 C By the fermentation of glucose
 D Gram positive
Ans. C

Explanation:

By the fermentation of glucose


Q. 3

The electron transport system of Neisseria is located on which of the following structures?

 A

Cytoplasmic membrane

 B

Mesosome

 C

Mitochondria

 D

Nuclear membrane

Q. 3

The electron transport system of Neisseria is located on which of the following structures?

 A

Cytoplasmic membrane

 B

Mesosome

 C

Mitochondria

 D

Nuclear membrane

Ans. A

Explanation:

Unlike eukaryotic cells in which the electron transport system is located on mitochondria, the electron transport system of bacteria is located on the cytoplasmic (plasma) membrane.
Mesosomes and polyribosome DNA aggregates are also found in bacterial cells and function in cell division and protein synthesis, respectively.
 
Bacteria do not have mitochondria or membrane-bounded nuclei.
 
Ref: Brooks G.F. (2013). Chapter 2. Cell Structure. In G.F. Brooks (Ed), Jawetz, Melnick, & Adelberg’s Medical Microbiology, 26e.

Q. 4

Differentiating feature of Neisseria gonococcus from Neisseria meningitides is ?

 A

Lactose fermentation

 B

Maltose fermentation

 C

Mannitol fermentation

 D

Sucrose fermentation

Q. 4

Differentiating feature of Neisseria gonococcus from Neisseria meningitides is ?

 A

Lactose fermentation

 B

Maltose fermentation

 C

Mannitol fermentation

 D

Sucrose fermentation

Ans. B

Explanation:

Ans. is ‘b’ i.e., Maltose fermentation


Q. 5

The virulence factor of Nisseria gonorrhoeae includes all of the following except-

 A

Outer membrane proteins 

 B

IgA protease

 C

M proteins

 D

Pili

Q. 5

The virulence factor of Nisseria gonorrhoeae includes all of the following except-

 A

Outer membrane proteins 

 B

IgA protease

 C

M proteins

 D

Pili

Ans. C

Explanation:

Ans. is ‘c’ i.e., M protein 

Virulence factors of gonococci

  • Gonococci have many virulence factors that enable it to estabish itself within an host and enhance its potential to cause disease.
  • Virulence factors may be divided into :-
  1.  Organism related
  2. Host related

Q. 6

All are true about Neisseria gonorrhoeae except ‑

 A

Gram positive cocci

 B

Cause stricture of urethra

 C

Involves seminal vesicles and spreads to epididymis

 D

Drug of choice is ceftriaxone

Q. 6

All are true about Neisseria gonorrhoeae except ‑

 A

Gram positive cocci

 B

Cause stricture of urethra

 C

Involves seminal vesicles and spreads to epididymis

 D

Drug of choice is ceftriaxone

Ans. A

Explanation:

Ans. is ‘a’ i.e., Gram positive cocci 

  • Gonocci are gram negative diplococci.
  • Urethral stricture may occur as a complication of gonococcal urethritis.
  • Gonococci may extend to seminal vesicle and epididymis, along the urethra.
  • For uncomplicated gonorrhea, single dose of ceftriaxone is DOC.

Q. 7

A patient with conjunctival infection, which lead to corneal perforation, was positive for Gram-negative coccoid appearance on Gram stain. Further investigation showed small translucent colourless organism which is oxidase positive. What could be the most probable causative organism-

 A

Moraxella catarrhalis

 B

Neisseria gonorrhea

 C

Psedomonas aeruginosa

 D

Acinetobacter actinatus

Q. 7

A patient with conjunctival infection, which lead to corneal perforation, was positive for Gram-negative coccoid appearance on Gram stain. Further investigation showed small translucent colourless organism which is oxidase positive. What could be the most probable causative organism-

 A

Moraxella catarrhalis

 B

Neisseria gonorrhea

 C

Psedomonas aeruginosa

 D

Acinetobacter actinatus

Ans. B

Explanation:

Ans. is ‘b’ i.e., Neisseria gonorrhea 


Q. 8

Selective media for N. gonorrhoeae –

 A

Thayer martin media

 B

Smith noguchi media

 C

Proskaur and Bech media

 D

Bordet gongue, media

Q. 8

Selective media for N. gonorrhoeae –

 A

Thayer martin media

 B

Smith noguchi media

 C

Proskaur and Bech media

 D

Bordet gongue, media

Ans. A

Explanation:

Ans. is ‘a’ i.e., Thayer martin media 


Q. 9

Genus neisseria is ‑

 A

Gram positive diplococci

 B

Gram negative diplococci

 C

Gram negative coccobacilli

 D

Gram positive bacilli

Q. 9

Genus neisseria is ‑

 A

Gram positive diplococci

 B

Gram negative diplococci

 C

Gram negative coccobacilli

 D

Gram positive bacilli

Ans. B

Explanation:

Ans. is ‘b’ i.e., Gram negative diplococci

The genus Neisseria consists of Gram negative aerobic nonsporulating, non motile oxidase positive cocci typically arranged in pairs (diplococci).



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