June 10, 2023
Sample for Neisseria Gonorrhoeae
- The best sample for men is the urethral discharge smear.
- Females can make a smear from the vagina.
- In females, a cervical smear can also be taken.
- An anal canal smear can be taken.
- Smears are made from prostatic secretions, urethra, cervix, and pelvic inflammatory disease.
Indications for Neisseria Gonorrhoeae
- A urethral smear is stained to diagnose gonorrhea.
- A cervical smear is stained to diagnose gonorrhea.
- It is advised to diagnose sexually transmitted diseases.
Introduction of Neisseria gonorrhoeae
- Neisseria gonorrhoeae causes contagious diseases and is usually sexually transmitted.
- Mother can transmit the disease to the newborn.
Bacteriology of Neisseria Gonorrhoeae
- N.Gonorrhoeae can infect any epithelium lined by columnar cells with cilia-like:
- But cannot vagina, which is the squamous epithelium.
- There are two pathogenic Neisseria:
- N. Gonorrhoeae (Gonococcus).
- N. Meningitides (Meningococcus).
- These are obligate parasites of the human urogenital area.
- These are characteristically seen in pairs with adjacent sides concave.
- In the purulent material, these are seen intracellularly and outside the cells.
- The incubation period is 2 to 10 days.
- These bacteria grow in enriched media (Chocolate agar).
- Incubation is done in a moist atmosphere containing 5 to 10% CO2.
- The optimal temperature is 35 to 37 C.
- These media may contain antibiotics (Lincomycin) to inhibit the growth of other bacteria.
- There are small gray glistening colonies after 24 hours of incubation, and they may become larger after 48 hours.
- The identification test is carbohydrate utilization, where it will produce acid only from glucose.
- N. Gonorrhoeae is gram-negative bacteria that can grow in the body, like the urethra, cervix, uterus, and fallopian tubes in females and the urethra in males.
- It grows in the warm, moist area of the female reproductive system.
- It can also grow in the mouth, throat, and anus.
Signs and symptoms of Neisseria Gonorrhoeae (Gonorrhea):
- Gonorrhea is not symptomatic in roughly 75% to 80% of the infected females and 10% to 15% of infected males.
- This is more symptomatic in men than in women.
- In the male:
- There is a urethral purulent discharge.
- There is dysuria.
- There may be proctitis and tenesmus.
- There is pelvic pain.
- In the female:
- Females are usually asymptomatic.
- Gonorrhea in females is symptomatic in about 75% to 80% and 19% to 15% in males.
- There is mucopurulent cervicitis.
- There is vaginal discharge.
- There may be dysuria.
- There may be proctitis.
- N. gonorrhea causes gonorrheal urethritis and initiates the majority of the case of acute salpingitis, a so-called pelvic inflammatory disease.
- Transmission from male to female is very efficient than female to male.
- While pharyngeal infections are asymptomatic.
- Ascending pelvic infection occurs in 10 to 20% of the cases, leading to infertility and ectopic pregnancy.
- This may involve the rectum and oropharynx.
- Oropharyngeal infection is present in 10% of females and 20% of homosexual men.
- Pharyngeal gonorrhea is usually asymptomatic, self-limited in 10 to 12 weeks, and visible in <50% of the cases.
- For the diagnosis, culture is needed, and the smear is not diagnostic because of the nonpathogenic Neisseria species.
- Gonococcal arthritis is diagnosed by the presence of gonococci in 1/3 of the cases.
- A variable number of WBCs are found, or synovial fluid may be purulent.
- Proctitis is seen in symptomatic cases (∼ 5%). Bacterial culture on special media is confirmatory.
- Avoid contamination from the stool.
- Rectal gonorrhea is accompanied by genital gonorrhea.
Gonorrhea disease In females:
- Vaginal discharge.
- Swollen lymph nodes.
- Bleeding after intercourse.
Gonorrhea disease in males:
- Urethritis (burning micturition).
- Swollen, painful testes.
- Enlarged lymph nodes in the throat.
Complications of Gonorrhea:
- In females ascending pelvic infection.
- Pelvic inflammatory disease (PID).
- There is salpingitis which leads to infertility.
- There may be gonococcal vulvovaginitis.
- There may be bartholinitis.
- In male:
- There may be cystitis.
- There may be prostatitis.
- There may be a urethral stricture.
- In the untreated mother, newborn babies can have Ophthalmia neonatorum (gonococcal conjunctivitis).
- There may be septicemia, arthritis, and meningitis due to the spread through the blood.
Diagnosis of Neisseria Gonorrhoeae
- In males, in the case of urethritis, there is urethral discharge. Make the smear from the urethral discharge.
- Now stain with gram stain, which will show gram-negative intracellular diplococci.
- The urethral smear is diagnostic and very specific.
- In the male, ask the patient to squeeze the penis to get a good amount of material.
- The patient can apply the material directly on the slide.
- Females can make a cervical smear and do the culture.
- Endocervical smears are positive in 50% of the cases.
- Swab smears are taken from:
- Endocervical canal.
- Anal canal.
- Smears may be tested by a fluorescent antibody test.
- When there is no discharge, insert the swab into the urethra up to 2 cm and gently rotate.
- Can take endocervical specimens under direct vision using a speculum.
- Other sites for the swab are the pharynx, anorectal area, blood, CSF, and synovial fluid.
- Ultimately can confirm the diagnosis by culture, and these bacteria need nutrient-rich selective agar media (Thayer-Martin).
- Culture needs 48 hours to form colonies.
- It can take conjunctival swabs in infants who have conjunctivitis.
- Blood and synovial fluid may be taken in case of arthritis.
- Gram-stained smears:
- Smear is positive when you find intracellular gram-negative diplococci.
- Extracellular organisms are not diagnostic.
- Extracellular gram-negative diplococci are not confirmatory.
- Smears are only 50% positive in asymptomatic patients. These patients must have the culture of the sample.
- The smear becomes negative within the start of the antibiotics in a few hours.
- In females, gram stain smears of the endocervical site are 45% to 65% positive.
- Smears from the vagina, oropharynx, and anal canal are not recommended.
- Urethral smears are >95% positive in symptomatic males.
- Smear is positive when you find intracellular gram-negative diplococci.
- Culture is done to supplement and confirm the diagnosis of gonorrhea.
- Culture is done on special media, Thayer-martin solid media.
- Take a culture sample before starting the antibiotics.
- The endocervical canal is the best site for the culture and is 82% to 92% positive.
- Rectal cultures are 30% to 50% positive. These are positive in homosexual cases.
- DNA probe tests are highly sensitive and specific.
- DNA amplification by PCR is good to test. It can be done on urine and swab specimen.
Treatment of Neisseria Gonorrhoeae
Sensitivity to antibiotics:
- These bacteria are sensitive to penicillin, ampicillin, tetracycline, macrolides, cefuroxime, and ciprofloxacin.
- Give a single oral dose of Amoxycillin or ampicillin.
- In 2% of the cases, gonorrhea is resistant to penicillin.
- Give probenecid to delay the excretion of medicine.
- Or a single dose of Ceftriaxone 250 mg I/M.
- Or a single dose of Norfloxacin 800 mg.
- Ciprofloxacin is given when an infection is complicated with Chlamydia infection.
- Erythromycin is given to pregnant ladies and children.
- The extragenital infection needs treatment for 5 to 7 days.
- Penicillin-resistant gonorrhea is treated with cefuroxime, cefotaxime, erythromycin, ciprofloxacin, tetracycline, or aztreonam.
Questions and answers:
Question 1: How to diagnose gonorrhea?
Intracellular gonococci are diagnostic.
Question 2: What is the special media for the growth of N. gonococci?
The special media Thay-Martin is needed.