Urinary Tract Infection
There is decreased predisposition to urinary tract infections
Treatment at a glance
- Cystitis: nitrofurantoin for 3–5 days, or cotrimoxazole if susceptible
- Pyelonephritis: ciprofloxacin or ceftriaxone
What our notes say
- There is decreased predisposition to urinary tract infections (Junior Clerkship in Reproductive Health (MBOG 4200): end of year examination, 4 )
- Urinary tract infections are more common in women because of the shorter urethra. (renal pathology — Past Paper Questions & Answers)
- Investigation of urinary tract infections is common in diagnostic microbiology laboratories. (FAIMSmicro 1 2006 — Past Paper Questions & Answers)
- Maternal and obstetric risks: premature rupture of membranes for more than 18 hours, chorioamnionitis, maternal fever, urinary tract infection or genital infection, GBS colonisation, prolonged or unclean delivery, and prematurity. (Integrated case paper: Medicine, Surgery, Gynaecology and Paediatrics (160 marks)
- A 75-year-old woman with recurrent urinary tract infections (Proteus on culture) has a staghorn calculus on CT. (Junior Clerkship in Internal Medicine (MBIM4100) main exam, Paper One: 31 Januar)
- Painful micturition with fever suggests a urinary tract infection, with white cells and bacteria in the urine. (Paediatrics main exam (MBPE 4300): 24 January 2022, Paper One, 100 MCQs, 2 short)
Study material on Urinary Tract Infection
- Bactriology Course Outline
- renal pathology
- Medical Bacteriology and Entomology MCQs
- Paediatrics end of 3rd trimester exam (MBPE 4300): 11 January 2022, congenital heart disease essay and 20 MCQs
- Medical Bacteriology and Entomology
Practice questions on Urinary Tract Infection
A 68-year-old man presents from a nursing home with fever, increased urinary frequency and urgency, and mental status changes. He has a penicillin allergy of anaphylaxis. Which of the following β-lactams is the most appropriate choice for gram-negative coverage of this patient's urinary tract infection?
- Aztreonam
- Ceftaroline
- Cefepime
- Ertapenem
- Primarily an incidental laboratory finding
Answer: A. Aztreonam is a monobactam with no cross-reactivity with penicillins and can be safely given to penicillin-allergic patients, even those with anaphylaxis. Although cross-reactivity between cephalosporins/carbapenems and penicillins is low (<1-10%), the risk rarely outweighs the benefit in cases of documented anaphylaxis. Aztreonam provides good gram-negative coverage for UTI. ---
Each of the following organisms is an important cause of urinary tract infections except
- Klebsiella pneumoniae
- Escherichia coli
- Bacteroides fragilis
- Proteus mirabilis Answer:
Answer: A. *Bacteroides fragilis* is an anaerobe associated with intra-abdominal infections/abscesses, not a typical UTI pathogen; the other three are classic uropathogens. --- ---
A 25-year-old sexually active female presents with urinary tract infection. The organism that is coagulase-negative and novobiocin resistant is
- Proteus mirabilis
- Escherichia coli
- Staphylococcus saprophyticus
- S. saprophyticus
- Reduced by routine feedback control
Answer: D. S. saprophyticus is novobiocin resistant and causes UTI in young sexually active women, being the second most common cause of UTI after E. coli. S. epidermidis is novobiocin sensitive, which helps differentiate these two coagulase-negative staphylococci. ---
A 23-year-old woman has a history of recurrent urinary tract infections, including at least one episode of pyelonephritis. Blood typing shows the P blood group antigen. Which of the following is likely to be the primary cause of her infections?
- Escherichia coli that produce heat-stable toxin
- Escherichia coli with K1 (capsular type 1) antigen
- Escherichia coli O139
- Escherichia coli with P-pili (fimbria
- Escherichia coli 0157:H7
Answer: D. P pili (P fimbriae) on uropathogenic E. coli specifically bind to P blood group antigens on uroepithelial cells. Patients with P antigens are more susceptible to pyelonephritis. P-piliated E. coli strains cause 90% of pyelonephritis cases in otherwise healthy individuals. ---
A 25-year-old sexually active female presents with urinary tract infection. The organism that is coagulase-negative and novobiocin resistant is
- Proteus mirabilis
- Escherichia coli
- S. saprophyticus
- Staphylococcus epidermidis
- Reduced by routine feedback control
Answer: C. S. saprophyticus is novobiocin resistant and causes UTI in young sexually active women. S. epidermidis is novobiocin sensitive. ---
A 25-year-old sexually active female presents with urinary tract infection. The organism that is coagulase-negative and novobiocin resistant is
- Staphylococcus saprophyticus
- Staphylococcus epidermidis
- Staphylococcus aureus
- Enterococcus faecalis
Answer: A. Staphylococcus saprophyticus is a common cause of urinary tract infections (UTIs), particularly in young, sexually active women. It is coagulase-negative and characteristically resistant to novobiocin, which helps differentiate it from other coagulase-negative staphylococci like Staphylococcus epidermidis, which is usually novobiocin-sensitive.