What causes uti in male teenager ? and is trimethoprim effective treatment for eliminating klebsiella species causing uti?

Usually?: Often male UTIs are a marker of an STD, poor personal (/penile) hygiene, or a known anatomic variance that interferes with urinary flow/clearance, or diabetes with poor control (causing sugar in urine). Consider above and address which most likely fits your situation. If UTI recurs, discuss above with Dr, as more testing may be needed. As long as not resistant, trimethoprim OK for klebsiella.