UTI

Case 1 G.N. is a 62‐year‐old woman who presents to the clinic with a 3‐day history of urinary frequency and dysuria. During the past 24 hours, she has had nausea, vomiting, and flank pain. One month before this visit, the patient received 3 days of cefpodoxime for an E. coli UTI. Six weeks before the E. coli UTI, the patient received a single 3‐g dose of amoxicillin for UTI‐like symptoms. This is her third UTI in 3 months. G.N. has a history of type 2 diabetes mellitus, which is poorly controlled with some diabetic‐related complications. G.N. also has hypertension and a history of several episodes of deep venous thrombosis.

Her medications include glyburide 5 mg/day orally, enalapril10 mg orally 2 times/day, warfarin 3 mg/day orally, and metoclopramide 10 mg 4 times/day. On physical examination, she is alert and oriented, with the following vital signs: temperature 102.8°F (39°C); heart rate 120 beats/minute; respiratory rate 16 breaths/minute; blood pressure (supine): 140/75 mm Hg; and blood pressure (standing) 110/60 mm Hg. Her laboratory values were within normal limits except for increased international normalized ratio 2.7; BUN 26 mg/dL; serum creatinine 1.88 mg/cL; and WBC 12,000 (78 polymorphonuclear leukocytes, 7 band neutrophils, 10 lymphocytes, and 5 monocytes).

Her urinalysis shows turbidity, 2+ glucose; pH 7. 0; protein 100 mg/c Her urinalysis shows turbidity, 2+ glucose; pH 7.0; protein 100 mg/c!L; 50‐100 WBC; + nitrites; 3‐5 red blood cells; and many bacteria and +casts. Which one of the following is the best empiric therapy for G.N..? A. TMP/SMZ double strength orally 2 times/day‐duration of antibiotics: 7 days. B. Ciprofioxacin 400 mg intravenously 2 times/day and then 500 mg orally 2 times/day‐duration of antibiotics: 10 days. C. Gentamicin 140 mg intravenously every 24 hours‐duration of antibiotics: 3 days. D. Ampicillin‐sulbactam 3 g intravenously every 6 hours and then amoxicillinclavulanate 875 mg orally 2 times/day‐duration of antibiotics: 10 days.

Answer B Although the treatment duration is correct for G.N.’s diagnosis (7 days), oral TMP/SMZ is inappropriate for complicated pyelonephritis. It will also interact with warfarin, increasing the risk of bleeding. Ciprofloxacin 400 mg intravenously 2 times/day and then 500mg orally 2 times/day for 10 days is an appropriate choice and duration (7–14 days) for this complicated pyelonephritis (it may also interact with warfarin, but to a lesser extent than TMP/SMZ). It would be expected to have activity against the common organisms causing complicated pyelonephritis. Gentamicin for 3 days is too short a treatment duration, and ampicillin sulbactam, followed by amoxicillin‐clavulanate, is not recommended for complicated pyelonephritis.

Case 2 L.B., a 45‐year‐old woman with type 1 diabetes mellitus, comes to the emergency department complaining of severe nausea, frequent vomiting, frequent urination, fever, shaking chills, and flank pain. Positive physical findings include a temperature of 39.4, a pulse of 110 beats/minute, blood pressure of 90/60 mm Hg, and CVA tenderness. A Gram stain of L.B.’s urine reveals gram‐negative rods, and a urinalysis demonstrates glucosuria, macroscopic hematuria, 20 to 25 WBC/LPF, numerous bacteria, and WBC casts.

She also has a blood sugar level of 400 mg/dL. L. B She also has a blood sugar level of 400 mg/dL. L.B. is admitted to the hospital with a diagnosis of acute bacterial pyelonephritis, and routine laboratory tests including a blood chemistry profile and complete blood count with differential, and specimens of urine and blood for C&S are ordered. L.B. is started on intravenous(IV) normal saline, ampicillin 1 g IV every 6 hours, and a sliding‐scale schedule of regular insulin based on every 6‐hour blood sugars. Which signs and symptoms in L.B. are consistent with pyelonephritis?

It is not always possible to differentiate clinically between upper and lower urinary tract infections. Symptoms common in lower UTI often are the only positive findings in upper UTI (i.e., subclinical pyelonephritis). however, this patient does manifest signs and symptoms of systemic infection consistent with acute bacterial pyelonephritis, including tachycardia, hypotension, fever, nausea and vomiting, shaking chills, flank pain, CVA tenderness, hematuria, and WBC casts. In addition, her diabetes may predispose her to various renal infections, including pyelonephritis, possibly because diabetic patients have altered antibacterial defense mechanisms.

Case 3 V.Q., a 20‐year‐old woman with no previous history of UTI, complains of burning on urination, frequent urination of a small amount, and bladder pain. She has no fever or CVA tenderness. A clean‐catch midstream urine sample shows gram‐negative rods on Gram stain. A urine sample for culture and susceptibility (C&S) testing is ordered, and the results of a urinalysis are as follows:

Appearance, straw‐colored (normal, straw) Specific gravity, 1.015 pH 8.0 Protein, glucose, ketones, bilirubin, and blood, all negative (normal, all negative) WBC, 10 to 15 cells/LPF (normal, 0–2 cells/LPF) Red blood cells (RBC), 0 to 1 cells/LPF (normal, 0–2 cells/LPF) Bacteria, many (normal, 0 to rare) Epithelial cells, 3 to 5 cells/LPF (normal, 0 to few cells/LPF)

Based on these findings, V. Q. is presumed to have a lower UTI Based on these findings, V.Q. is presumed to have a lower UTI. What should be the goals of therapy of V.Q.’s infection at this time? What factors should be considered before selecting an antibiotic for V.Q.?

‐ Goal of therapy o effectively eradicate the infection o prevent associated complications, o minimizing adverse effects and costs associated with drug therapy

Initiation of Therapy o started before C&S results are known o A urine C&S may be obtained before antibacterial therapy and repeated 2 to 3 weeks after the completion of therapy o resistance to agents is common Ampicillin resistance has been reported in as many as 25% to 70% TMP‐SMX resistance has significantly increased in recent years and may be as high as 20% to 30%  discouraged in geographic areas where the incidence of E. coli resistance exceeds 15% to 20%

fluoroquinolones have become favored agents in many geographic areas with high rates of resistance to ampicillin, TMP‐SMX, and trimethoprim because of excellent activity against common urinary pathogens and the ability to use short 3‐day courses of therapy.

Case 4 TW. is a 28‐year‐old woman with a history of recurrent infections who now exhibits a new E. coli UTI. Her last episode occurred 5 months previously. Her current infection is treated with TMP-SMX for 10 days. A repeat UA was scheduled for the completion of antibiotic therapy, but she canceled her appointment because she “felt fine”. Twelve weeks later, she returns to the clinic with signs and symptoms of another UTI. The only other medication she has taken is an oral contraceptive. Why would C&S testing of a urine sample be especially useful at this time?

‐ Relapse: infection with the same organism within 14 days of discontinuing antibiotics for the preceding UTI ‐ Re-infection: infection with a completely different organism‐most common cause of recurrent cystitis

Case 5 W.R. is a 28‐year‐old woman who presents to the clinic with a 2‐day history of dysuria, frequency, and urgency. She has no significant medical history, and the only drug she takes is oral contraceptives. Which one of the following is the best empiric therapy for N.R.? A. Oral amoxicillin 3 g in a single dose. B. Oral ciprofloxacin 500 mg 2 times/day for 7 days. C. Oral trimethoprim‐sulfamethoxazole (TMP/SMZ) double strength 2 times/day for 3 days. D. Oral cephalexin 500 mg 4 times/day for 3 days.

Answer C Single‐dose therapy is not recommended because of decreased cure rates and inadequate treatment of potential upper UTI s. Ciprofloxacin is an appropriate choice, but 7 days of therapy is not necessary. The best choice for this patient is TMP/SMZ double strength 2 times/day orally for 3 days. The patient should be counseled about the potential interaction between antibiotics and oral contraceptives. β‐Lactams are not as effective as TMP/SMZ or fluoroquinolones, and data are limited on their use for 3 days.

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