Which pathogens are commonly implicated in community-acquired urinary tract infections?

• A. Enterococcus faecalis and Streptococcus pyogenes
• B. Klebsiella pneumoniae and Pseudomonas aeruginosa
• C. Proteus mirabilis and Neisseria gonorrhoeae
• D. Escherichia coli and Staphylococcus saprophyticus

Answer: (D)

In community-acquired urinary tract infections, the most common offender is Escherichia coli because it normally resides in the gut and has virulence traits that promote urinary tract colonization, including adhesins that allow binding to urothelial cells. Staphylococcus saprophyticus is the next frequent cause, especially in young sexually active women, due to its ability to colonize the periurethral area and ascend into the bladder during intercourse. The other organisms listed are less typical for uncomplicated, community-acquired UTIs: Enterococcus faecalis is more common in healthcare-associated or older patients; Streptococcus pyogenes is not a usual urinary pathogen; Klebsiella pneumoniae and Pseudomonas aeruginosa are more linked to healthcare-associated or complicated UTIs; Proteus mirabilis can cause UTIs and is associated with stone formation; Neisseria gonorrhoeae causes STI-related urethritis rather than a typical community-acquired UTI.