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Gonococci
Neisseria gonorrhoeae, a pathogenic gram-negative diplococcus, causes gonorrhea, the second most common sexually transmitted disease worldwide. It primarily infects mucosal surfaces such as the urethra, cervix, and throat, and can lead to serious complications like pelvic inflammatory disease or disseminated infections. Diagnosis typically involves culture from samples or gram staining, and treatment includes antibiotics like cefixime or ceftriaxone, with evaluation of recent sexual partners necessary.
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Gonococci
- 1. Gonococci Gram Negative cocci Attribution-NonCommercial-ShareAlike4.0 International (CC BY- For B.Sc Optometry Students
- 2. Neisseria • Neisseria isthe 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).
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- 6. Pathogenesis • Once insidethe 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 cells and may even be transported through the cells to the intercellular spaces and subepithelial tissue.
- 7. Pathogenesis • Phagocytes, suchas neutrophils, also may contain gonococci inside vesicles • Because the gonococci are intracellular at this time, the host’s defenses have little effect on 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
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- 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 • Gonococcicauses both localized infections, usually in the genital tract, and disseminated infections. • Gonorrhoea in 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 intermenustrual bleeding (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 midpalmar lesion on an erythematous base
- 15. Gonococcal Ophthalmia inthe Adult Marked chemosis and tearing Typically purulent discharge, erythema STD Atlas, 1997
- 16. Gonococcal Ophthalmia inthe Adult Conjunctival erythema and discharge
- 17. Vertical Transmission andNeonatal 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 • Gonorrhealeye 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 neonatorumprophylaxis: • Silver nitrate 1% aqueous solution topical x 1 • Erythromycin 0.5% ointment topical x 1 • Tetracycline 1% ointment topical x 1 Ophthalmia neonatorum treatment: • Ceftriaxone 25-50 mg/kg IV or IM x 1 NTE(not to exceed) 125 mg
- 20. Gonorrhea Screening inPregnancy • 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 inPregnancy • Postpartum endometritis • Septic abortions • Post-abortal PID 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 • Formen, 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 Veillonella or 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 ThayerMartin Medium {Chocolate agar containing antibiotics (vancomycin, colistin, trimethoprim, and nystatin)} is most often used. Modified Newyork City 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 forNeisseria 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 • Cefixime 400mg PO x 1 or • Ceftriaxone 125 mg IM x 1 or • Ciprofloxicin 500 mg PO x 1 or • Ofloxacin 400 mg PO x 1 or • Levofloxacin 500 mg PO x 1 • Azithromycin 1 g PO x 1 or • Doxycycline 100 mg PO BID x 7 d All sex partners within past 60 days need evaluation and treatment