Gonococci

Neisseria gonorrhoeae is the obligate human pathogen that causes the sexually transmitted disease (STD) gonorrhea. This Gram-negative diplococci/gonococci does not infect other animals or experimental animals and does not survive freely in the environment. The gonococcal infection occurs in the upper or lower tract, pharynx, ophthalmic area, rectum, and bloodstream. During the 1980’s gonorrhea was also referred to as “the clap” when public awareness was quite minimal. This was one of the venereal diseases prostitutes hoped to contract since it resulted in infertility by pelvic inflammatory disease (PID). As documentation, diagnostic testing, and public awareness improved, there has been a decline in incidence reports, however, it is still considered a very common infectious disease.

1. Gonococci
Gram Negative cocci
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2. Neisseria
•Neisseria is the only pathogenic gram negative cocci (precisely diplococci).
•Neisseria meningitidis
•Neisseria gonorrhoeae.
•Human beings are only known hosts of N.gonorrhoeae.
•Neisseria gonorrhoeae (often called gonococcus) causes gonorrhoea, the
second most common sexually transmitted disease (STDs) of worldwide
importance (Chlamydial infections are more common).
•It causes disease only in humans.
•Neisseria gonorrhoeae does not thrive in the environment and grows in a
CO2 environment, therefore, the urethra, cervix, rectum, and throat are the
main sites of infection.

3. Structure and Characteristics
•gram-negative, oxidase-positive, diplococcus
•These bacteria are also referred to as gonococci.
•They causes an acute, infectious, sexually transmitted disease of the mucous membranes
of the genitourinary tract, eye, rectum, and throat
•In urethral discharge it is predominately found within the polymorphs
•Sensitive to dehydration and cold conditions.
•Gonococci do not contain capsules (Meningococci does).

4. Culture

5. Virulence factors expressed by Neisseria gonorrhoeae

6. Pathogenesis
•Once inside the body the gonococci attach to
the microvilli of mucosal cells by means of pili
and protein II,which function as adhesins.
•This attachment prevents the bacteria from
being washed away by normal cervical and
vaginal discharges or by the flow of urine
•They are then phagocytosed by the mucosal
cellsand may even be transported through
the cells to the intercellular spacesand
subepithelial tissue.

7. Pathogenesis
•Phagocytes, such as neutrophils, also may contain gonococci inside vesicles
•Because the gonococci are intracellular at this time, the host’s defenses
have little effecton the bacteria.
•Following penetration of the bacteria, the host tissue responds locally by
the infiltration of mast cells, more PMNs, and anitbody-secreting plasma
cells.
•These cells are later replaced by fibrous tissue that may lead to urethral
closing, or stricture, in males

8. Pathogenesis

9. Signs and symptoms
•Half of women with gonorrhea do not have symptoms, whereas others have
vaginal discharge, lower abdominal pain, or pain with sexual intercourse
associated with inflammation of the uterine cervix
•Most infected men with symptoms have inflammation of the penile urethra
associated with a burning sensation during urination and discharge from the
penis.
•The incubation period is 2 to 14 days, with most symptoms appearing between 4
and 6 days after infection.

10. Diseases caused
•Gonococci causes both localized infections, usually in the genital tract, and
disseminated infections.
•Gonorrhoeain men is characterized primarily by urethritis accompanied by dysuria
and a purulent discharge. Epididymitis can occur.
•In women, infection is located primarily in the endocervix, causing a purulent
vaginal discharge and intermenustrualbleeding (cervicitis). The most frequent
complication in women is an ascending infection of the uterine tubes (salphingitis,
Pelvic Inflammatory Disease), which can result in sterility or ectopic pregnancy as
a result of scarring of tissues.

11. Disseminated gonococcal Infections
•In both genders, disseminated gonococcal infection with bacteremia may occur.
•Disseminated gonococcal infections occurs via the blood stream.
•Gonococcal strains causing disseminated infections are usually resistant to serum
and complement.
•This can lead to involvement of:
joints (gonorrheal arthritis)
Tendon sheath inflammation (tenosynovitis)
heart (gonorrheal endocarditis)
pharynx (gonorrheal pharyngitis)
Meninges (gonorrheal meningitis)
Localized skin infections

12. Disseminated gonococcal Infections
Necrotic, grayish
central lesion on
erythematous base

13. Disseminated gonococcal Infections
Papular and
pustular lesions on
the foot

14. Disseminated gonococcal Infections
Small painful
midpalmarlesion
on an
erythematous
base

15. Gonococcal Ophthalmia in the Adult
Marked chemosis
and tearing
Typically purulent
discharge,
erythema
STD Atlas, 1997

16. Gonococcal Ophthalmia in the Adult
Conjunctival
erythema and
discharge

17. Vertical Transmission and Neonatal
Complications on Gonorrhea
•Overall vertical transmission rate ~30%
•Neonatal complications include:
•Ophthalmia neonatorum
•Disseminated gonococcal infection (sepsis, arthritis, meningitis)
•Scalp abscess (if fetal scalp monitor used)
•Vaginal and rectal infections
•Pharyngeal infections

18. Opthalmia neonatorum
•Gonorrheal eye infections can occur in
newborns as they pass through an
infected birth canal.
•Lid edema, erythema and marked
purulent discharge
•The resulting disease is called
ophthalmia neonatorum, or
conjunctivitis of the newborn.
•This was once a leading cause of
blindness in many parts of the world.

19. Opthalmia neonatorum
Ophthalmia neonatorum prophylaxis:
•Silver nitrate 1% aqueous solution topical x 1
•Erythromycin 0.5% ointment topical x 1
•Tetracycline 1% ointment topical x 1
Ophthalmia neonatorum treatment:
•Ceftriaxone25-50 mg/kg IV or IM x 1 NTE(not to exceed)125
mg

20. Gonorrhea Screening in Pregnancy
•Screen in 1st trimester and again in 3rd trimester (~32 weeks) for high-risk
or high prevalence patients
•High risk includes new partners, multiple partners, non-mutually
monogamous relationship, concurrent STDs
•Higher prevalence among adolescents, urban, low SES, certain geographic
areas

21. Gonococcal Complications in Pregnancy
•Postpartum endometritis
•Septic abortions
•Post-abortalPID
Possible role in:
•Gestational bleeding
•Preterm labor and delivery
•Premature rupture of membranes

22. Diagnosis
Sample: Urethral/Cervical/Vaginal discharge
•To obtain a urethral specimen swab ( cotton or rayon swab) is inserted
approximately 2cm in urethra and rotated gently before withdrawing.
•If there is profuse urethral discharge in male, it can be collected without
inserting the swab.
•A few drops of first voided urine can be used in males, but the sensitivity is
low compared to discharge.

23. Diagnosis
Gram Staining
•For men, a gram-stained smear of urethral discharge (exudate) showing
intracellular Gram-negative diplococci is diagnostic.
•But as women may carry normal vaginal flora such as Veillonellaor occasional
gram-negative coccobacilli , may resemble gonococci
•In case of women may not be diagnostic so culture and identification process
is needed, which is a confirmatory test.

24. Diagnosis
Culture
•Modified Thayer Martin Medium {Chocolate agar containing antibiotics
(vancomycin, colistin, trimethoprim, and nystatin)} is most often used.
Modified NewyorkCity Medium (MNC) is also used for the culture of Neisseria
gonorrhoeae. MNC also supports the growth of Mycoplasma.
Biochemical tests for Neisseria gonorrhoeae identification
•Oxidase Test: Positive
•Ferments glucose but not maltose, sucrose or lactose
•DNase Test: Negative
•Beta-galactosidase (ONPG) Test: Negative
•Glutamyl-aminopeptidase (GAP) Test: Negative

25. Diagnosis
Biochemical tests for Neisseria gonorrhoeae identification
•Oxidase Test: Positive
•Ferments glucose but not maltose, sucrose or lactose
•DNase Test: Negative
•Beta-galactosidase (ONPG) Test: Negative
•Glutamyl-aminopeptidase (GAP) Test: Negative
Other methods
•Enzyme-linked immunosorbent assay (ELISA)is also used as a rapid test and is
sensitive to gonorrhea.
•PCR method or Nucleic Acid Amplification Tests (NAATs)

26. Treatment
•Cefixime400 mg PO x 1 or
•Ceftriaxone 125 mg IM x 1 or
•Ciprofloxicin500 mg PO x 1 or
•Ofloxacin 400 mg PO x 1 or
•Levofloxacin500 mg PO x 1
•Azithromycin1 g PO x 1 or
•Doxycycline 100 mg PO BID x 7 d
All sex partners within past 60 days need evaluation and treatment