American Board of Internal Medicine (ABIM) Certification Practice Exam

Which organism is the most common cause of uncomplicated acute bacterial prostatitis?

1. Staphylococcus aureus

2. Escherichia coli

3. Enterococcus faecalis

4. Proteus mirabilis

The correct answer is: Escherichia coli

The most common cause of uncomplicated acute bacterial prostatitis is Escherichia coli. This organism is a Gram-negative bacterium that is normally found in the intestines but can cause various infections when it translocates to other areas of the body, such as the urinary tract and prostate. In cases of acute bacterial prostatitis, Escherichia coli has been shown to be the leading pathogen in numerous studies, particularly in younger and middle-aged men, who are most commonly affected. Infection generally arises from ascending infection from the urethra or bladder into the prostate, where E. coli can proliferate, leading to the signs and symptoms of prostatitis, which include fever, pelvic pain, and urinary difficulties. The other organisms listed, while they can cause infections under certain circumstances, are less frequently implicated in uncomplicated acute bacterial prostatitis. For instance, Staphylococcus aureus is primarily associated with systemic infections and not typically involved in uncomplicated prostatitis cases. Enterococcus faecalis is more often linked to urinary tract infections but is not as prevalent as E. coli in prostatitis. Proteus mirabilis can be present in urinary tract infections but also does not have the same prominence in causing acute bacterial prostatitis as Escherichia coli