20-year-old female patient presents with a 2-day history of dysuria, lower abdominal pain and low-grade fever. Her urine is cloudy with pyuria and abundant grampositive bacteria.
She is a college student who is sexually active with no previous history of sexually transmitted diseases. Which organism is most likely responsible for this woman’s symptoms?
a. Enterococcus faecalis
b. Escherichia coli
c. Neisseria gonorrhoeae
d. Staphylococcus saprophyticus
e. Candida albicans
The answer is d. The patient’s urinary tract infection (UTI) is caused by gram-positive bacteria. This excludes E coli and N gonorrhoeae, both of which are gram-negative, and C albicans, which is a yeast.
Enterococcus faecalis and S saprophyticus are gram-positive bacteria that can cause UTI, but the second agent is a more likely cause of UTI in young women.
Staphylococcus saprophyticus colonizes the rectum or the urogenital tract of approximately 5% to 10% of women and is second only to E coli as the causative agent of uncomplicated urinary tract infections in young sexually active women.
Such infections are successfully treated with fluoroquinolones or trimethoprim-sulfamethoxazole.