Gonorrhea — MCQs
What structure of Neisseria gonorrhoeae is primarily responsible for its pathogenicity?
Which of the following is NOT a virulence factor of Cryptococcus?
A 20-year-old man presents with dysuria, urgency, and urethral discharge. Physical examination shows suppurative urethritis, with redness and swelling at the urethral meatus. Which of the following is the most likely etiology of urethritis in this patient?
A 24-year-old woman presents with vaginal discharge, dysuria, and lower abdominal pain. On examination, there is cervical motion tenderness and mucopurulent cervical discharge. What is the diagnostic test of choice?
A 25-year-old male presents with a burning sensation during urination and purulent discharge from the penis, which started 5 days ago. He reports unprotected sexual intercourse with a new partner two weeks ago. Examination reveals an erythematous urethral meatus with noticeable purulent discharge. A Gram stain of the discharge reveals intracellular gramnegative diplococci. The patient is otherwise healthy with no known drug allergies. What is the most appropriate treatment for this patient?
A 25-year-old male presents with purulent urethral discharge and dysuria for 3 days. Gram stain shows intracellular gram-negative diplococci. What is the most appropriate empirical treatment regimen according to current CDC guidelines?
A patient with multiple sexual exposures is diagnosed with gonorrhea. What is the appropriate treatment?
What is the most sensitive test for Chlamydia in asymptomatic carriers?
Which of the following statements about lymphogranuloma venereum (LGV) is true?
Which STI has the highest rates of antibiotic resistance?
Gonorrhea Indian Medical PG Practice Questions and MCQs
Question 1: What structure of Neisseria gonorrhoeae is primarily responsible for its pathogenicity?
- A. Pili (Correct Answer)
- B. Capsule
- C. Flagella
- D. Endotoxin
Explanation: ***Pili*** - **Pili** enable *Neisseria gonorrhoeae* to adhere to host epithelial cells, which is crucial for colonization and initiation of infection. - They also facilitate evasion of the host immune response by undergoing **antigenic variation**, making it difficult for the immune system to recognize and eliminate the bacteria. *Capsule* - While some bacterial species use a **capsule** for immune evasion and adherence, *Neisseria gonorrhoeae* does not typically possess a prominent capsule. - Its pathogenicity is primarily attributed to other factors like pili and outer membrane proteins. *Flagella* - **Flagella** provide motility to bacteria, but *Neisseria gonorrhoeae* is a non-motile bacterium and does not possess flagella. - Therefore, flagella do not contribute to its pathogenicity. *Endotoxin* - **Endotoxin** (specifically **lipooligosaccharide, LOS**, in *Neisseria*) does contribute to the pathology of gonococcal infections by causing inflammation and tissue damage. - However, the primary factor for initial adherence and colonization, which is essential for establishing infection, is the **pili**.
Question 2: Which of the following is NOT a virulence factor of Cryptococcus?
- A. Polysaccharide capsule
- B. Ability to make melanin
- C. Production of protease (Correct Answer)
- D. Urease production
Explanation: ***Production of protease*** - While *Cryptococcus neoformans* can produce some proteolytic enzymes, **protease production is not considered a major or classical virulence factor** in standard medical microbiology literature. - Unlike the other three factors listed, proteases are not prominently featured as key virulence mechanisms in *Cryptococcus* pathogenesis for medical education purposes. - The primary virulence factors emphasized for *Cryptococcus* are the capsule, melanin, and urease. *Polysaccharide capsule* - The **polysaccharide capsule** is the MOST important virulence factor, protecting the yeast from phagocytosis and immune clearance. - It interferes with antigen presentation, antibody binding, and complement activation, making it crucial for survival in the host. *Ability to make melanin* - **Melanin production** protects *Cryptococcus* from oxidative stress, free radicals, UV radiation, and antifungal agents. - It contributes to survival in macrophages and persistence in the central nervous system. *Urease production* - **Urease production** enables *Cryptococcus* to cross the blood-brain barrier and colonize the central nervous system. - Urease hydrolyzes urea into ammonia, causing local alkalinization that facilitates CNS invasion and contributes to meningoencephalitis.
Question 3: A 20-year-old man presents with dysuria, urgency, and urethral discharge. Physical examination shows suppurative urethritis, with redness and swelling at the urethral meatus. Which of the following is the most likely etiology of urethritis in this patient?
- A. Haemophilus ducreyi
- B. Chlamydia trachomatis
- C. Ureaplasma urealyticum
- D. Neisseria gonorrhoeae (Correct Answer)
Explanation: ***Neisseria gonorrhoeae*** - The presentation of **dysuria, urgency, urethral discharge**, and **suppurative urethritis** (purulent discharge with redness and swelling) is highly characteristic of **gonococcal urethritis** [1]. - **Gonorrhea** is a common cause of sexually transmitted urethritis, especially with prominent inflammatory signs [1]. *Haemophilus ducreyi* - This bacterium is the causative agent of **chancroid**, which typically presents as painful genital ulcers with regional lymphadenopathy. - It does not cause urethritis with significant urethral discharge as described. *Chlamydia trachomatis* - While *Chlamydia trachomatis* is a common cause of urethritis, it typically causes **non-gonococcal urethritis (NGU)**, which is often less symptomatic and may present with a thinner, mucoid discharge [1]. - The **suppurative (purulent) nature** of the discharge described points more strongly towards gonorrhea [1]. *Ureaplasma urealyticum* - *Ureaplasma urealyticum* is a known cause of **non-chlamydial, non-gonococcal urethritis**, similarly to *Chlamydia* [1]. - However, its presentation is generally milder and less suppurative than that caused by *Neisseria gonorrhoeae* [1].
Question 4: A 24-year-old woman presents with vaginal discharge, dysuria, and lower abdominal pain. On examination, there is cervical motion tenderness and mucopurulent cervical discharge. What is the diagnostic test of choice?
- A. Culture on modified Thayer-Martin medium
- B. Wet mount examination
- C. Gram stain of cervical secretions
- D. Nucleic acid amplification test (NAAT) (Correct Answer)
Explanation: ***Nucleic acid amplification test (NAAT)*** - NAATs are the **most sensitive and specific** tests for detecting *Chlamydia trachomatis* and *Neisseria gonorrhoeae*, common causes of cervicitis, which is suggested by the patient's symptoms (vaginal discharge, dysuria, lower abdominal pain, cervical motion tenderness, mucopurulent discharge). - They can be performed on **non-invasive samples** (e.g., urine, vaginal swabs), making them convenient and preferred for screening and diagnosis. *Culture on modified Thayer-Martin medium* - While **gonococcal culture** on modified Thayer-Martin medium is a specific test, it has **lower sensitivity** compared to NAATs and is more labor-intensive. - It is often reserved for cases where **antibiotic resistance testing** is needed or when NAATs are unavailable. *Wet mount examination* - A **wet mount** can identify motile trichomonads (*Trichomonas vaginalis*), yeast (candidiasis), and clue cells (bacterial vaginosis). - However, it **does not diagnose cervicitis** caused by *Chlamydia* or *Gonorrhea*, which are strongly suspected given the cervical motion tenderness and mucopurulent discharge. *Gram stain of cervical secretions* - A **Gram stain** can identify gram-negative intracellular diplococci suggestive of **gonorrhea**, but its **sensitivity is variable** in women, especially in asymptomatic cases, and it cannot detect chlamydia. - It is **insufficient for definitive diagnosis** of chlamydial infection or as a sole diagnostic tool for gonorrhea due to its lower sensitivity compared to NAATs.
Question 5: A 25-year-old male presents with a burning sensation during urination and purulent discharge from the penis, which started 5 days ago. He reports unprotected sexual intercourse with a new partner two weeks ago. Examination reveals an erythematous urethral meatus with noticeable purulent discharge. A Gram stain of the discharge reveals intracellular gramnegative diplococci. The patient is otherwise healthy with no known drug allergies. What is the most appropriate treatment for this patient?
- A. Metronidazole 500 mg orally twice daily for 7 days
- B. Doxycycline 100 mg orally twice daily for 7 days
- C. Ceftriaxone 500 mg intramuscularly
- D. Cefixime 400 mg orally once (Correct Answer)
Explanation: ***Cefixime 400 mg orally once*** - This patient presents with symptoms and a Gram stain consistent with **gonococcal urethritis** (**intracellular gram-negative diplococci**) [1]. - Oral cefixime is an alternative first-line option for **uncomplicated gonococcal infections** when intramuscular ceftriaxone is not feasible or available [1]. *Metronidazole 500 mg orally twice daily for 7 days* - **Metronidazole** is primarily used to treat **anaerobic bacterial infections** and **parasitic infections** (e.g., trichomoniasis, bacterial vaginosis). - It is not effective against **Neisseria gonorrhoeae**, the causative agent of this patient's condition. *Doxycycline 100 mg orally twice daily for 7 days* - **Doxycycline** is the treatment of choice for **Chlamydia trachomatis infections** and is often co-administered empirically with gonorrhea treatment due to high rates of co-infection [1]. - While it addresses potential chlamydial co-infection, it is not the primary treatment for **gonococcal urethritis** itself. *Ceftriaxone 500 mg intramuscularly* - **Ceftriaxone 500 mg IM (or 1 gram in some guidelines)** is the **preferred first-line treatment for uncomplicated gonococcal infections** due to its high efficacy and single-dose administration [1]. - While an excellent choice, the question asks for the *most appropriate* given the options, and oral cefixime is an acceptable alternative, especially in scenarios where IM injections are impractical.
Question 6: A 25-year-old male presents with purulent urethral discharge and dysuria for 3 days. Gram stain shows intracellular gram-negative diplococci. What is the most appropriate empirical treatment regimen according to current CDC guidelines?
- A. Ceftriaxone 500mg IM single dose + Azithromycin 1g oral single dose (Correct Answer)
- B. Azithromycin 2g oral single dose
- C. Doxycycline 100mg oral twice daily for 7 days
- D. Ceftriaxone 1g IM single dose
Explanation: ***Ceftriaxone 500mg IM single dose + Azithromycin 1g oral single dose*** - This regimen is the recommended empirical treatment for **uncomplicated gonococcal infections** according to current CDC guidelines, covering both *N. gonorrhoeae* and potential co-infection with *C. trachomatis*. [1] - The **intracellular gram-negative diplococci** on Gram stain are highly suggestive of **Neisseria gonorrhoeae**, and the addition of azithromycin addresses potential **chlamydial co-infection**. [1] *Azithromycin 2g oral single dose* - While azithromycin is used to treat **Chlamydia**, a 2g dose alone as monotherapy is not recommended for suspected gonococcal urethritis due to increased **resistance concerns** and lack of optimal efficacy against *N. gonorrhoeae*. - This regimen would not adequately cover **gonorrhea**, especially given the evidence of gram-negative diplococci. *Doxycycline 100mg oral twice daily for 7 days* - Doxycycline is the primary treatment for **chlamydial infections**, but it is **not effective** as monotherapy for **gonorrhea**. - Using doxycycline alone for suspected gonococcal urethritis would result in **treatment failure** for the likely gonococcal infection. *Ceftriaxone 1g IM single dose* - **Ceftriaxone** is the cornerstone of gonorrhea treatment, but the recommended dose for uncomplicated infection is **500mg IM**. [1] A 1g dose is typically reserved for severe or disseminated cases. - More importantly, **monotherapy with ceftriaxone** is generally not recommended due to the high prevalence of **chlamydial co-infection**, which would not be treated with ceftriaxone alone.
Question 7: A patient with multiple sexual exposures is diagnosed with gonorrhea. What is the appropriate treatment?
- A. Acyclovir
- B. Cefixime
- C. Doxycycline
- D. Ceftriaxone (Correct Answer)
Explanation: ***Ceftriaxone*** - **Ceftriaxone** is the **first-line recommended treatment** for uncomplicated gonorrhea according to **CDC and WHO guidelines**. - Administered as a **single intramuscular injection (500 mg IM)**, it provides highly effective coverage against *Neisseria gonorrhoeae* with minimal resistance. - It works by inhibiting bacterial cell wall synthesis, and is the **gold standard therapy** for gonorrhea treatment. - For patients with multiple sexual exposures, empiric treatment for co-infection with *Chlamydia trachomatis* (doxycycline) should also be considered. *Cefixime* - **Cefixime** was previously used as an oral alternative but is **no longer recommended** as first-line therapy due to **increasing resistance** of *N. gonorrhoeae*. - The CDC removed cefixime from recommended regimens due to **inferior efficacy** compared to ceftriaxone and concerns about treatment failures. - While it is an oral cephalosporin, it is **not appropriate first-line therapy** for gonorrhea. *Doxycycline* - **Doxycycline** is commonly used to treat **co-infection with *Chlamydia trachomatis***, which frequently occurs alongside gonorrhea. - The typical regimen is **100 mg twice daily for 7 days** as adjunctive therapy. - However, doxycycline is **not effective as monotherapy for gonorrhea** and should not be used alone to treat *N. gonorrhoeae* infection. *Acyclovir* - **Acyclovir** is an **antiviral medication** used to treat **herpes simplex virus (HSV)** infections. - It works by inhibiting viral DNA replication and has **no activity against bacterial infections** like gonorrhea. - It would be completely ineffective against *Neisseria gonorrhoeae*.
Question 8: What is the most sensitive test for Chlamydia in asymptomatic carriers?
- A. Tissue culture
- B. Serology
- C. Direct fluorescent antibody test (DFA)
- D. NAAT (Nucleic Acid Amplification Test) (Correct Answer)
Explanation: ***NAAT (Nucleic Acid Amplification Test)*** - **NAATs** detect **Chlamydia trachomatis DNA or RNA**, making them highly sensitive and specific for diagnosing chlamydial infections, especially in asymptomatic individuals. - They can be performed on easily obtained samples like **urine** or **vaginal swabs**, making them ideal for screening. *Tissue culture* - While historically considered the gold standard, **tissue culture** is labor-intensive, expensive, and less sensitive than NAATs. - Its sensitivity is significantly reduced in asymptomatic carriers due to lower bacterial loads. *Serology* - **Serology** detects antibodies to Chlamydia, which indicates past exposure rather than current infection. - It is not useful for diagnosing acute or asymptomatic infections. *Direct fluorescent antibody test (DFA)* - **DFA** involves staining a sample with fluorescent antibodies to directly visualize Chlamydia organisms. - It has lower sensitivity and specificity compared to NAATs, especially in asymptomatic individuals with fewer organisms.
Question 9: Which of the following statements about lymphogranuloma venereum (LGV) is true?
- A. Primary genital ulcer is always painless
- B. Rarely leads to proctocolitis
- C. Caused by C. trachomatis serovars L1, L2, L3 (Correct Answer)
- D. Groove sign is pathognomonic
Explanation: Caused by C. trachomatis serovars L1, L2, L3 - Lymphogranuloma venereum (LGV) is specifically caused by **invasive serovars** L1, L2, and L3 of *Chlamydia trachomatis*. [1] - These serovars differ from the non-invasive serovars (A-K) that cause **genital chlamydial infections** and trachoma, as they are capable of systemic dissemination. *Primary genital ulcer is always painless* - The primary lesion of LGV, often a **papule or shallow ulcer**, appears at the site of inoculation and is typically **painless and transient**, often going unnoticed. [1] - While generally painless, in some cases, it can become **ulcerated and painful**, particularly if superinfected. *Rarely leads to proctocolitis* - **Proctocolitis** is a common manifestation of LGV, particularly in individuals engaging in receptive anal intercourse, due to direct lymphatic spread from the rectum. [1] - It can cause severe symptoms such as **rectal pain, discharge, tenesmus**, and **constipation**, progressing to fibrosis and strictures. [1] *Groove sign is pathognomonic* - The **"groove sign"**, characterized by visible depression between swollen inguinal and femoral lymph nodes, is highly suggestive of LGV but is **not pathognomonic** as it can occur in other conditions causing massive regional lymphadenopathy. - This sign indicates extensive involvement of both inguinal and femoral lymph node chains, a common feature of advanced LGV. [1]
Question 10: Which STI has the highest rates of antibiotic resistance?
- A. Chancroid
- B. Donovanosis
- C. Gonorrhea (Correct Answer)
- D. Syphilis
Explanation: ***Gonorrhea*** - *Neisseria gonorrhoeae* has progressively become resistant to many classes of antibiotics, including **sulfonamides, penicillin, tetracycline, macrolides, fluoroquinolones, and early cephalosporins.** [1] - **Emergence of resistance** is largely due to the organism's unique ability to acquire resistance genes and acquire genetic mutations, coupled with a high mutation rate, making it a significant public health concern. [1] *Chancroid* - Caused by **_Haemophilus ducreyi_**, which typically responds well to macrolides (e.g., azithromycin) or cephalosporins (e.g., ceftriaxone). - While resistance can occur, it is **not as widespread or severe** as with *Neisseria gonorrhoeae*. *Donovanosis* - Caused by **_Klebsiella granulomatis_**, which is generally treatable with macrolides like azithromycin or doxycycline. - **Antibiotic resistance is relatively uncommon** and does not pose a major clinical challenge. *Syphilis* - Caused by **_Treponema pallidum_**, which remains highly susceptible to penicillin, the primary treatment. - While **penicillin allergies** necessitate alternative treatments, true antibiotic resistance in *T. pallidum* is rare and has **not significantly impacted treatment efficacy**.
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