An 18-year-old female college student presents to student health services with a complaint of a burning sensation while urinating and abdominal pain. She denies urinary urgency or increased frequency. She has no signifi cant past medical history. She is currently sexually active with a new partner. She does not use barrier contraception. She denies any previous history of sexually transmitted diseases. On examination she is afebrile, heart rate is 70/min, and blood pressure is 120/60 mm Hg. Examination reveals no peritoneal signs but there is tenderness to palpation over the suprapubic region. On pelvic examination the cervix appears edematous and friable with a small amount of discharge from the os. A urine sample reveals numerous WBCs but no organisms on Gram stain. A cervical swab is sent for Gram stain and culture. Which of the following is the most likely explanation for these findings? (A) Infection with Chlamydia trachomatis (B) Infection with Escherichia coli (C) Infection with Neisseria gonorrhoeae (D) Infection with Proteus mirabilis (E) Interstitial cystitis
A. Chlamydia trachomatis. As she presents with urethritis following intercourse with a new partner and gram staining is negative; chlamydia is an obligate intracellular organism. Also the other most common UTI (e. Coli, S. Saprophyticus) all stain and UA will also have positive Nitrite (E. Coli) and urease (s. Saprophyticus).