Neiserria gonorrhoeae

Neiserria gonorrhoeae, gram Negative, Cocci, Diplococci, Classification, Structure, Shape, Morphology, Growth characteristics, Culture Characteristics, Biochemical reaction, Growth Media, Infections caused by Neiserria gonorrhoeae, diagnosis , treatments

1. Neisseria gonorrhoeae Lecture 03 (B)

2. Neisseria gonorrhoeae (Gonococcus) N. gonorrhoeae causes the sexually transmitted disease gonorrhoea . first described by Neisser in 1879 in gonorrheal pus. resembles meningococci very closely in many properties.

3. MORPHOLOGY: Gram negative oval/spherical cocci usually found with in the polymorphs Arranged in pairs (adjacent sides concave) Kidney shaped possess pili on their surface

4. CULTURE & CULTURAL CHARACTERISTICS: fastidious organisms do not grow on ordinary culture media. aerobic but may grow anaerobically also The optimum temperature for growth is 35-36°C & optimum pH is 7.2-7.6. It is essential to provide 5-10% CO2.

5. Media used: Non selective media: Chocolate agar, Mueller-Hinton agar Modified New York City medium b) Selective media: Thayer Martin medium with antibiotics (Vancomycin, Colistin & Nystatin)

6. Colony morphology Colonies are small round translucent convex or slightly umbonate finely granular surface lobate margins.

7. Biochemical reactions: 1) Oxidase test: Positive 2) Ferments only glucose but not maltose.

8. PATHOGENICITY:

9. Antigenic structure & virulence factors: 1. Pili 2. Lipooligosaccharide : Endotoxic . 3. Outer membrane proteins: 3 types a) Protein I ( por )- it is a porin & helps in adherence. b) Protein II ( opa )- helps in adherence. c) Protein III ( rmp )- it is associated with protein I. 4. IgA1 protease: Splits & inactivates IgA

10. Antigenic structure & virulence factors

11. Mechanism of pathogenesis: Gonococci adhere to epithelial cells of urethra or other mucosal surface through pili penetrate through the intercellular space reach the sub epithelial connective tissue & causes inflammation Leads to clinical manifestations Incubation period: 2-8 days.

12. Disease In men: The disease starts as an acute urethritis with a muco-purulent discharge extends to the prostate, seminal vesicles & epididymis In some it may become chronic urethritis The infection may spread to the peri -urethral tissues, causing abscesses & multiple discharging sinuses

13. Diseases In women: The initial infection is urethritis & cervicitis but vaginitis does not occur in adult female ( vulvovaginitis can occur in prepubertal girls) The infection may extend to Bartholin’s glands, endometrium & fallopian tubes causing Pelvic Inflammatory Disease (PID) Rarely peritonitis may develop with perihepatic

14. In both the sexes: Proctitis , pharyngitis, conjunctivitis, bacteraemia which may lead to metastatic infection such as arthritis, endocarditis, meningitis, pyemia & skin rashes.

15. LABORATORY DIAGNOSIS: In men: a) Acute infection- Urethral discharge b) Chronic infection) Morning drop ii) Discharge collected after prostatic massage iii) Centrifuged deposit of urine B) In women: i ) Urethral discharge ii) Cervical swabs

16. In both the sexes:

17. A) Direct microscopy: Gram staining: Smear provides a presumptive evidence of gonorrhea in men. Gram negative diplococci are found. But it is unreliable in women.

18. Immunofluorescence:

19. Serology:

20. TREATMENT: Previously Penicillin was drug of choice but resistance developed rapidly. Penicillin resistant is due to production of penicillinase enzyme & the strains are called as p enicillinase p roducing N eisseria g onorrhoeae ( PPNG ). Now Ceftriaxone or Ciprofloxacin plus Doxycycline or Erythromycin is useful.

21. EPIDEMIOLOGY: Gonorrhoea is an exclusively human disease. The only source of infection is a human carrier or less often a patient. Asymptomatic carriage in women makes them a reservoir to spread infection among their male contact. Gonorrhoea is an venereal disease (STD)

22. PROPHYLAXIS:

23. COMMENSAL NEISSERIAE N. lactamica N.pharyngis N. polysaccreae N. cinerea N. flavescens N. mucosa