Urinary Tract Infections — MCQs
Which one of the following gram-positive organisms is the most common cause of UTI among sexually active women?
Most common cause of UTI in young females is?
Which of the following statements about screening for chlamydia and gonorrhea is MOST accurate?
A 25 year old female, presents to the clinic with dysuria, urinary frequency and urgency. After a laboratory workup a diagnosis of cystitis is made. Which is the first line drug for the treatment for this patient?
A man presents with a history of dysuria and urethral discharge after having unprotected sexual intercourse. What is the treatment of choice for this infection?
An 8-year-old boy during a routine checkup is found to have E. coli 100,000 CFU/mL on a urine culture, obtained by mid-stream clean-catch void. The child is asymptomatic. Which is the most appropriate next step in the management?
A 27-year-old man presents with clear urethral discharge and dysuria for 3 days. Gram stain shows numerous polymorphonuclear leukocytes without intracellular diplococci. What is the most likely pathogen?
Female treated for Urinary tract infection now has vaginal discharge. The most likely organism is?
Commonest organism giving rise to urinary tract infection:
Ectopic ureter may be frequently associated with which of the following conditions?
Urinary Tract Infections Indian Medical PG Practice Questions and MCQs
Question 1: Which one of the following gram-positive organisms is the most common cause of UTI among sexually active women?
- A. Staphylococcus aureus
- B. Staphylococcus saprophyticus (Correct Answer)
- C. Enterococcus
- D. Staphylococcus epidermidis
Explanation: ***Staphylococcus saprophyticus*** - This organism is a common cause of **urinary tract infections (UTIs)**, particularly in sexually active young women. - It is known for its ability to adhere to uroepithelial cells and is **novobiocin-resistant**, distinguishing it from other coagulase-negative staphylococci. *Staphylococcus aureus* - While *Staphylococcus aureus* can cause UTIs, it's typically associated with **catheter-associated infections** or hematogenous spread, not primarily UTIs in sexually active women. - It is a **coagulase-positive** staphylococcus and often linked to more severe infections. *Enterococcus* - **Enterococci**, such as *Enterococcus faecalis*, are a common cause of UTIs, especially in hospitalized patients or those with urinary tract abnormalities. - However, they are less frequently the primary cause in otherwise healthy, sexually active women compared to *S. saprophyticus*. *Staphylococcus epidermidis* - *Staphylococcus epidermidis* is part of the normal skin flora and is a common **contaminant** in urine cultures. - It infrequently causes true UTIs and is generally only pathogenic in immunocompromised individuals or those with **indwelling medical devices**.
Question 2: Most common cause of UTI in young females is?
- A. Klebsiella
- B. Proteus
- C. Staph saprophyticus
- D. E. coli (Correct Answer)
Explanation: ***E. coli*** - **Uropathogenic *E. coli*** (*UPEC*) is the most prevalent bacterium responsible for uncomplicated UTIs in otherwise healthy young women. - Its virulence factors, such as **P-fimbriae** (adhesins), allow it to attach to uroepithelial cells and colonize the urinary tract effectively. *Klebsiella* - While *Klebsiella pneumoniae*: can cause UTIs, it is more commonly associated with **hospital-acquired infections** or UTIs in patients with **comorbidities** or instrumentation. - It ranks significantly lower than *E. coli* as a cause of community-acquired UTIs in young females. *Proteus* - *Proteus mirabilis* is known for causing UTIs, especially those associated with **struvite kidney stones** due to its **urease activity**. - However, its incidence as a cause of UTI in young females is much less frequent compared to *E. coli*. *Staph saprophyticus* - **Staphylococcus saprophyticus** is a common cause of UTIs in young, sexually active women, accounting for a significant percentage [1]. - While it is a notable cause, **it is still less common than *E. coli***, which is overwhelmingly the leading pathogen in this demographic.
Question 3: Which of the following statements about screening for chlamydia and gonorrhea is MOST accurate?
- A. Screening is not cost-effective and should be avoided in low-risk populations
- B. Screening is recommended for sexually active women under 25, men who have sex with men, and pregnant women (Correct Answer)
- C. Screening is only recommended for patients with symptoms
- D. Annual screening is recommended for all sexually active adults regardless of age or risk factors
Explanation: ***Screening is recommended for sexually active women under 25, men who have sex with men, and pregnant women*** - This statement aligns with current **CDC guidelines** which prioritize screening in populations with a higher prevalence or increased risk of complications from chlamydia and gonorrhea. - Early detection and treatment in these groups can prevent serious long-term health consequences like **pelvic inflammatory disease (PID)**, **infertility**, and **adverse pregnancy outcomes**. *Screening is not cost-effective and should be avoided in low-risk populations* - While screening in genuinely low-risk populations might be less cost-effective, chlamydia and gonorrhea often have **asymptomatic presentations**, making targeted screening essential for disease control. - The long-term costs associated with untreated infections (e.g., infertility treatment, chronic pain) often outweigh the costs of screening, even in lower-prevalence settings, when focused on at-risk groups. *Screening is only recommended for patients with symptoms* - This statement is incorrect because a significant proportion of chlamydia and gonorrhea infections are **asymptomatic**, meaning individuals can be infected and transmit the infection without showing any symptoms. - Relying only on symptoms would lead to widespread **undetected infections** and continued transmission within communities. *Annual screening is recommended for all sexually active adults regardless of age or risk factors* - While broad screening might seem comprehensive, current guidelines emphasize **targeted screening** based on age, sexual history, and risk factors to optimize resource allocation and maximize public health impact. - Overly broad screening in genuinely low-risk older populations may not be the most **cost-effective strategy**.
Question 4: A 25 year old female, presents to the clinic with dysuria, urinary frequency and urgency. After a laboratory workup a diagnosis of cystitis is made. Which is the first line drug for the treatment for this patient?
- A. Cephalexin
- B. Norfloxacin
- C. Amoxicillin
- D. Nitrofurantoin (Correct Answer)
Explanation: ***Nitrofurantoin*** - **Nitrofurantoin** is the most widely recommended first-line antibiotic for uncomplicated **cystitis** due to its excellent efficacy against common urinary pathogens, especially **E. coli**. - It achieves high concentrations in the urine and has a low rate of resistance, making it an excellent choice for this condition. - It is preferred over other antibiotics due to antimicrobial stewardship principles and minimal impact on gut flora. *Cephalexin* - While generally effective against some urinary pathogens, **cephalexin** is typically reserved as a second-line agent for uncomplicated cystitis, particularly if there are contraindications to or resistance to first-line agents. - Its broad-spectrum activity may contribute to increased resistance development if used routinely as first-line. *Norfloxacin* - **Norfloxacin** is a **fluoroquinolone** that, while effective for UTIs and sometimes used in regional practice, is generally not recommended as the preferred first-line for uncomplicated cystitis due to concerns about increasing antibiotic resistance and potential for serious side effects (e.g., tendinitis, QT prolongation, CNS effects). - Current antimicrobial stewardship guidelines recommend reserving fluoroquinolones for more complicated urinary tract infections or when other first-line options are not suitable. *Amoxicillin* - **Amoxicillin** is generally not recommended as a first-line agent for cystitis due to high rates of **bacterial resistance**, particularly among **E. coli** strains, which are the most common cause of UTIs. - Its efficacy against common urinary pathogens is often lower compared to other first-line options.
Question 5: A man presents with a history of dysuria and urethral discharge after having unprotected sexual intercourse. What is the treatment of choice for this infection?
- A. Erythromycin
- B. Azithromycin
- C. Ceftriaxone (Correct Answer)
- D. Penicillin G
Explanation: ***Ceftriaxone*** - The combination of **dysuria** and **urethral discharge** following unprotected sexual intercourse is highly suggestive of **gonorrhea**. - **Ceftriaxone** is the recommended first-line treatment for uncomplicated gonococcal infections due to increasing antibiotic resistance. *Erythromycin* - Erythromycin is primarily used for atypical bacterial infections, such as those caused by *Mycoplasma pneumoniae* or *Chlamydia trachomatis*. - While it can be used for chlamydia, it is not the preferred treatment for suspected gonorrhea. *Azithromycin* - Azithromycin is often used in combination with ceftriaxone for gonorrhea to cover potential co-infection with **Chlamydia trachomatis**. - However, **monotherapy with azithromycin is not recommended for gonorrhea** due to concerns about emerging resistance and suboptimal efficacy. *Penicillin G* - Penicillin G was historically used to treat gonorrhea, but this is no longer the case due to widespread **resistance** of *Neisseria gonorrhoeae* strains. - Its primary use now is for susceptible bacterial infections, such as syphilis and certain streptococcal infections.
Question 6: An 8-year-old boy during a routine checkup is found to have E. coli 100,000 CFU/mL on a urine culture, obtained by mid-stream clean-catch void. The child is asymptomatic. Which is the most appropriate next step in the management?
- A. Prophylactic antibiotics for 6 months
- B. Administer long term urine alkalinizer
- C. Treat as an acute episode of urinary tract infection
- D. No therapy (Correct Answer)
Explanation: ***No therapy*** - The presence of **bacteria** in the urine (**bacteriuria**) without any accompanying symptoms like fever, dysuria, or flank pain is defined as **asymptomatic bacteriuria (ASB)**. - In healthy, asymptomatic children, ASB generally requires **no antibiotic treatment**, as it rarely progresses to symptomatic infection or causes renal damage and may even protect against symptomatic UTIs by competitive inhibition. *Treat as an acute episode of urinary tract infection* - This child is **asymptomatic,** therefore, he does not have an acute urinary tract infection (UTI). - Treating asymptomatic bacteriuria can lead to **antibiotic resistance** and unnecessary side effects without clinical benefit. *Prophylactic antibiotics for 6 months* - **Prophylactic antibiotics** are reserved for children with recurrent symptomatic UTIs or significant anatomical abnormalities like **vesicoureteral reflux (VUR)**, which are not indicated here. - Using long-term antibiotics in an asymptomatic child can contribute to the development of **antibiotic-resistant organisms**. *Administer long term urine alkalinizer* - **Urine alkalinizers** are used in specific conditions like certain types of **kidney stones (e.g., uric acid stones)** or to enhance the excretion of certain drugs, not for asymptomatic bacteriuria. - There is **no evidence** to support the use of urine alkalinizers in managing asymptomatic bacteriuria or preventing UTIs.
Question 7: A 27-year-old man presents with clear urethral discharge and dysuria for 3 days. Gram stain shows numerous polymorphonuclear leukocytes without intracellular diplococci. What is the most likely pathogen?
- A. Neisseria gonorrhoeae
- B. Trichomonas vaginalis
- C. Ureaplasma urealyticum
- D. Chlamydia trachomatis (Correct Answer)
Explanation: ***Chlamydia trachomatis*** - The presentation of **clear urethral discharge** and **dysuria** in a sexually active young man, coupled with polymorphonuclear leukocytes on Gram stain but **no intracellular diplococci**, is highly characteristic of **chlamydial urethritis**. - *Chlamydia trachomatis* causes **non-gonococcal urethritis** and is a common cause of sexually transmitted infections (STIs). *Neisseria gonorrhoeae* - This pathogen typically causes **purulent urethral discharge** and would show **intracellular Gram-negative diplococci** on microscopy, which were absent in this case. - Gonococcal urethritis is usually associated with more severe symptoms and a different Gram stain finding. *Trichomonas vaginalis* - While *Trichomonas vaginalis* can cause urethritis in men, it is less common than in women and typically presents with a **foamy, greenish discharge** and may be associated with **pruritus**. - *Trichomonas* is not visible on Gram stain; diagnosis requires **wet mount microscopy** showing motile trophozoites, making this less likely given the laboratory findings. *Ureaplasma urealyticum* - *Ureaplasma urealyticum* can cause **non-gonococcal urethritis**, but it is generally associated with **milder symptoms** or can even be asymptomatic. - While it's a possibility, *Chlamydia trachomatis* is a more common and prominent cause of the described clinical picture.
Question 8: Female treated for Urinary tract infection now has vaginal discharge. The most likely organism is?
- A. Candida (Correct Answer)
- B. Trichomonas
- C. Ureaplasma urealyticum
- D. Chlamydia
Explanation: ***Candida*** - Antibiotic treatment for a **urinary tract infection** can disrupt the normal vaginal flora, leading to an overgrowth of **Candida albicans**, which is a common cause of vaginal discharge. - This often presents as **vulvovaginal candidiasis** with thick, white, "cottage cheese-like" discharge and intense pruritus. *Trichomonas* - **Trichomonas vaginalis** is a sexually transmitted infection (STI) that causes greenish-yellow, frothy vaginal discharge with a foul odor [1]. - While it can cause vaginal discharge, it is less likely to be directly precipitated by antibiotic use for a UTI compared to candidiasis. *Ureaplasma urealyticum* - **Ureaplasma urealyticum** can cause non-gonococcal urethritis and cervicitis, and sometimes vaginal discharge, but it is not typically associated with a flare-up following antibiotic treatment for a UTI. - It is often considered part of the normal genitourinary flora or an opportunistic pathogen. *Chlamydia* - **Chlamydia trachomatis** is a common sexually transmitted bacterium [2] that can cause cervicitis, leading to vaginal discharge, often mucopurulent and subtle [1]. - It would not typically emerge as a direct consequence or overgrowth due to antibiotic treatment for a UTI, unlike fungal infections.
Question 9: Commonest organism giving rise to urinary tract infection:
- A. Staphylococcus
- B. E. coli (Correct Answer)
- C. Proteus
- D. Streptococcus
Explanation: ***E. coli*** - **Uropathogenic E. coli (UPEC)** is the most frequent cause of **uncomplicated urinary tract infections (UTIs)**, accounting for 75-95% of cases. - Its virulence factors, such as **fimbriae (pili)**, enable it to adhere to the uroepithelium and resist flushing by urine flow. *Staphylococcus* - **Staphylococcus saprophyticus** is a common cause of UTIs, particularly in sexually active young women, but it is less common than *E. coli* overall. - **Staphylococcus aureus** can cause UTIs, often in healthcare-associated settings or in patients with indwelling catheters, but it is not the most common causative agent. *Proteus* - **Proteus mirabilis** is known for causing UTIs, especially those associated with **struvite kidney stones** due to its production of urease, which alkalinizes urine. - It is a significant pathogen but ranks lower in prevalence compared to *E. coli*. *Streptococcus* - **Group B Streptococcus (Streptococcus agalactiae)** can cause UTIs, particularly in pregnant women and neonates. - However, streptococcal species are generally not the most common cause of UTIs in the general population.
Question 10: Ectopic ureter may be frequently associated with which of the following conditions?
- A. Dysuria
- B. Paradoxical incontinence (Correct Answer)
- C. Bilateral hydroureter
- D. Oliguria
Explanation: ***Paradoxical incontinence*** - Ectopic ureters in females often insert distal to the external sphincter (e.g., vagina, vestibule), leading to **continuous leakage of urine** despite periods of normal voiding. This is known as paradoxical incontinence, where the bladder fills and empties normally, but urine also constantly dribbles from the ectopic opening. - In males, ectopic ureters usually insert proximal to the external sphincter (e.g., prostatic urethra, seminal vesicle) and therefore rarely cause incontinence but rather present with **ureteral obstruction** or **epididymitis**. *Oliguria* - **Oliguria** refers to a decreased urine output and is typically associated with **renal failure**, dehydration, or severe obstruction, not directly or frequently with an ectopic ureter itself. - An ectopic ureter may cause obstruction leading to **hydronephrosis** or renal damage, which could eventually lead to oliguria, but it is not the immediate or frequent direct association. *Dysuria* - **Dysuria** means painful urination, most commonly associated with **urinary tract infections (UTIs)**, urethritis, or bladder inflammation. - While an ectopic ureter can predispose to UTIs, dysuria is a symptom of infection rather than a direct, frequent consequence of the anatomical anomaly itself. *Bilateral hydroureter* - **Bilateral hydroureter** suggests obstruction of both ureters, often at the level of the bladder or urethra, or a systemic condition affecting both kidneys. - An ectopic ureter is usually a unilateral anomaly, causing **unilateral hydroureter** if it is obstructed, not typically bilateral.
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