A 35 year old man presents to an emergency depament with an exquisitely tender prostate gland. An acute bacterial infection is suspected. Which of the following organisms is the most common pathogen in this setting?

The disease is acute bacterial prostatitis; the usual route of infection is by direct extension from a bladder or urethral source. Less commonly, hematogenous or lymphatic spread from a distant site may occur. The most commonly isolated organism is Escherichia coli; other common pathogens include Klebsiella, Proteus, Pseudomonas, Enterobacter, Serratia, Enterococcus, and Staphylococcus aureus. Enterobacter, Klebsiella, Proteus, and Pseudomonas are all gram-negative rods that can cause acute bacterial prostatitis, but they are not as common as Escherichia coli. Ref: Cooper C.S., Joudi F.N., Williams R.D. (2010). Chapter 38. Urology. In G.M. Dohey (Ed), CURRENT Diagnosis & Treatment: Surgery, 13e.