"Emphysematous prostatitis is typically a complication of acute bacterial prostatitis, which itself is often a complication of urinary tract infections that ascend to the prostatic ducts 1-3. Causative pathogens are generally Gram negative organisms, such as Klebsiella pneumoniae (most common in one review 1), Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis 1-4."
"urinary retention (e.g. bladder obstruction, neurogenic bladder)"