What Is Urinary Tract Infection?
Urinary tract infection (UTI) is a bacterial infection or inflammation of the bladder (cystitis), kidneys (pyelonephritis), or urethra (urethritis), leading to bacterial colonization of the urine. Infection of the urinary tract is a common problem, causing more than eight million office visits annually in the United States. UTI is the second most common infection that affects women. UTIs typically affect young, sexually active women. A lower UTI is an infection or inflammation of the bladder or urethra. Upper UTIs involve infections of the ureters and kidneys. Simple or uncomplicated UTIs are infections experienced by women with no significant history of UTIs and are characterized by new onset of mild to moderate symptoms. A complicated UTI commonly occurs due to structural or functional abnormality of the urinary tract. UTIs can be due to acute or chronic infections (Buttaro, Trybulski, Bailey, & Sandberg-Cook, 2011).
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Risk factors for UTIs include stool contamination, history of past urinary tract infection, low fluid intake, irregular bladder emptying, vaginal pH lower than 4.5, sexual intercourse, failure to void within 10 to 15 minutes of sexual intercourse, diaphragm or spermicide use, symptomatic partner, pregnancy, menopause, hyperuricemia, neurogenic bladder, kidney disease, urologic abnormalities, and immunocompromised (Buttaro et al., 2011).
Symptoms of acute uncomplicated UTIs are due to bladder irritation exhibiting signs of increased frequency, urgency, dysuria, and occasional hematuria. An uncomplicated UTI is a rare occurrence in the affected individual who is otherwise healthy. Usually, there are a small number of responsible pathogens vulnerable to first-line narrow-spectrum antimicrobial agents, and there are no urologic or gynecologic abnormalities. A complicated presentation including high fever, chills, flank pain, costovertebral angle tenderness, nausea, and vomiting is indicative of pyelonephritis or urosepsis (Buttaro et al.,
2011). A urinalysis is essential when the patient presents with urinary symptoms indicative of an UTI. It is advised that urine dipstick tests be used to guide treatment decisions in healthy women younger than 65 years whose UTI symptoms are mild, or presents with less than two symptoms (Shah & Goundrey-Smith, 2013). A urine dipstick provides rapid diagnostics by assessing the presence of leukocytes, nitrites, blood, protein, and/or bacteria. The presence of nitrites and leukocytes indicates bacteria in the urine, which causes urinary nitrates to breakdown into nitrites. A higher concentration of the leukocyte esterase enzyme will be present in the urine due to the increased presence of neutrophils with infection. In addition to the information obtained from the dipstick, microscopy can be used to detect hematuria, pyuria (white cells in the urine), or bacteriuria to confirm the type of bacteria and guide antibiotic selection in complicated UTI or pyelonephritis (kidney infection). A urine culture is needed for upper UTI, complicated UTI, unsuccessful treatment or reinfection of UTI (Buttaro et al., 2011). There is a 90% probability that a urine culture would be positive for a UTI if a patient presents with severe symptoms or with at least three or more of the common urinary signs and symptoms, dysuria, urinary frequency, urinary urgency, suprapubic pain or tenderness, hematuria, and polyuria. A positive nitrite test, with or without a positive leukocyte result, indicates a probable UTI (Shah & Goundrey-Smith, 2013). Nonpharmacologic measures have shown to prevent sporadic or frequent UTIs. Sexual intercourse and failure to void within 10 to 15 minutes after sexual intercourse are the two main influences most consistently associated with UTIs. In discussing the association between these two factors and UTIs with a patient, the provider must distinguish between UTIs and STIs. Explanations and suggestions must be presented in a way that is nonjudgmental without implying guilt. It should be suggested to void within 10 to 15 minutes after sexual intercourse, drink plenty of water (64 to 80 ounces/day), urinate frequently, wipe front to back, and avoid feminine products that include deodorants, avoid close-fitting or synthetic underwear, vaginal douching to decrease the occurrence of UTIs (Buttaro et al., 2011). Regular consumption of cranberries supplementation in the form of juice, concentrate, or capsule has shown to have a positive role in preventing UTIs. Studies have shown cranberry as having preventative capabilities for UTI symptoms. Cranberries consist of anthocyanins, which may inhibit bacterial adhesion to the urinary tract. A meta-analysis in 2012 determined that adults who consumed cranberry juice on a regular basis were 38% less likely to develop symptoms of UTI, and the juice was more effective than cranberry capsules or tablets (Bass-Ware, Weed, Johnson, & Spurlock, 2014).
Medication Synthesis
A wide range of antibiotic agents is effective in treating UTIs; however, selection must be made carefully due to resistance of bacteria. Common and avoidable reasons for treatment failure include inappropriate antibiotic selection, subtherapeutic dosing, adverse reactions, and inadequate treatment duration. Antibiotics used to treat routine UTIs include trimethoprim-sulfamethoxazole (TMP-SMZ), ampicillin, cephalosporins, fluoroquinolones, and nitrofurantoin. Most infections respond to three-day antibiotic courses of TMP-SMZ, a fluoroquinolone, or nitrofurantoin (Buttaro et al., 2011). Criteria for antibiotic selection for treatment of urinary tract infections (UTIs) include type of urinary tract infection (acute uncomplicated, complicated, recurrent), microorganism susceptibility (culture and sensitivity), likelihood of bacterial resistance, adequate antimicrobial concentration achieved in urine, toxicity, and anticipated side effects (Buttaro et al., 2011). TMP-SMZ (Bactrim) is a widely used combination antibiotic consisting of sulfamethoxazole and trimethoprim which interferes with folate synthesis. Sulfamethoxazole inhibits bacterial folic acid synthesis and growth through the blockage of dihydrofolic acid synthesis from para-aminobenzoic acid. Trimethoprim prevents dihydrofolic acid reduction to tetrahydrofolate causing inhibition of enzymes needed for the folic acid pathway (Lexi-Comp, 2016). TMP-SMZ (Bactrim) is bacteriolytic and inexpensive; therefore, it is considered the antibiotic of choice for N.M., who is suffering from acute uncomplicated UTI. Bacterial eradication and cure rates are higher than 85% to 90. Three day antimicrobial regimens have been shown to give the same cure rate as traditional 7 to 10 day courses in at least 90% of women (Buttaro et al., 2011). It is recommended that a double strength tablet, 160 mg trimethoprim–800 mg sulfamethoxazole, be administered every 12 hours for 3-5 days for uncomplicated UTI. As a result, the course of treatment for N.M. will consist of one tablet of 160 mg trimethoprim–800 mg sulfamethoxazole twice daily for three days. It is vital to discuss the importance of taking the antibiotics as prescribed to ensure effectiveness (Lexi-Comp, 2016). Possible side effects of TMP-SMZ to consider for this patient include fever, rash, pruritus, photosensitivity, neutropenia, thrombocytopenia, anorexia, nausea and vomiting, and Stevens-Johnson syndrome. It is essential to discuss potential side effects so the patient is aware of potential effects, how to respond if such effects occur, and when to notify the provider.
The use of TMP-SMZ has been associated with embryo-fetal toxicity; therefore, N.M. should receive a pregnancy test prior to initiating therapy. Additionally, a culture and sensitivity, CBC, serum potassium, creatinine, and BUN should be obtained prior to initiating therapy (Lexi-Comp, 2016). TMP-SMZ may induce drug interactions with common medications including angiotensin-converting-enzyme inhibitors (ACE inhibitors), angiotensin II receptor blockers (ARBs), antidiabetic agents, carvedilol, and phenytoin. These interactions must be considered when prescribing TMP-SMZ. Currently, N.M. is not prescribed other medications, so that is not a concern at this moment (Lexi-Comp, 2016).
Risk factors for UTIs include stool contamination, history of past urinary tract infection, low fluid intake, irregular bladder emptying, vaginal pH lower than 4.5, sexual intercourse, failure to void within 10 to 15 minutes of sexual intercourse, diaphragm or spermicide use, symptomatic partner, pregnancy, menopause, hyperuricemia, neurogenic bladder, kidney disease, urologic abnormalities, and immunocompromised (Buttaro et al., 2011).
Symptoms of acute uncomplicated UTIs are due to bladder irritation exhibiting signs of increased frequency, urgency, dysuria, and occasional hematuria. An uncomplicated UTI is a rare occurrence in the affected individual who is otherwise healthy. Usually, there are a small number of responsible pathogens vulnerable to first-line narrow-spectrum antimicrobial agents, and there are no urologic or gynecologic abnormalities. A complicated presentation including high fever, chills, flank pain, costovertebral angle tenderness, nausea, and vomiting is indicative of pyelonephritis or urosepsis (Buttaro et al.,
2011). A urinalysis is essential when the patient presents with urinary symptoms indicative of an UTI. It is advised that urine dipstick tests be used to guide treatment decisions in healthy women younger than 65 years whose UTI symptoms are mild, or presents with less than two symptoms (Shah & Goundrey-Smith, 2013). A urine dipstick provides rapid diagnostics by assessing the presence of leukocytes, nitrites, blood, protein, and/or bacteria. The presence of nitrites and leukocytes indicates bacteria in the urine, which causes urinary nitrates to breakdown into nitrites. A higher concentration of the leukocyte esterase enzyme will be present in the urine due to the increased presence of neutrophils with infection. In addition to the information obtained from the dipstick, microscopy can be used to detect hematuria, pyuria (white cells in the urine), or bacteriuria to confirm the type of bacteria and guide antibiotic selection in complicated UTI or pyelonephritis (kidney infection). A urine culture is needed for upper UTI, complicated UTI, unsuccessful treatment or reinfection of UTI (Buttaro et al., 2011). There is a 90% probability that a urine culture would be positive for a UTI if a patient presents with severe symptoms or with at least three or more of the common urinary signs and symptoms, dysuria, urinary frequency, urinary urgency, suprapubic pain or tenderness, hematuria, and polyuria. A positive nitrite test, with or without a positive leukocyte result, indicates a probable UTI (Shah & Goundrey-Smith, 2013). Nonpharmacologic measures have shown to prevent sporadic or frequent UTIs. Sexual intercourse and failure to void within 10 to 15 minutes after sexual intercourse are the two main influences most consistently associated with UTIs. In discussing the association between these two factors and UTIs with a patient, the provider must distinguish between UTIs and STIs. Explanations and suggestions must be presented in a way that is nonjudgmental without implying guilt. It should be suggested to void within 10 to 15 minutes after sexual intercourse, drink plenty of water (64 to 80 ounces/day), urinate frequently, wipe front to back, and avoid feminine products that include deodorants, avoid close-fitting or synthetic underwear, vaginal douching to decrease the occurrence of UTIs (Buttaro et al., 2011). Regular consumption of cranberries supplementation in the form of juice, concentrate, or capsule has shown to have a positive role in preventing UTIs. Studies have shown cranberry as having preventative capabilities for UTI symptoms. Cranberries consist of anthocyanins, which may inhibit bacterial adhesion to the urinary tract. A meta-analysis in 2012 determined that adults who consumed cranberry juice on a regular basis were 38% less likely to develop symptoms of UTI, and the juice was more effective than cranberry capsules or tablets (Bass-Ware, Weed, Johnson, & Spurlock, 2014).
Medication Synthesis
A wide range of antibiotic agents is effective in treating UTIs; however, selection must be made carefully due to resistance of bacteria. Common and avoidable reasons for treatment failure include inappropriate antibiotic selection, subtherapeutic dosing, adverse reactions, and inadequate treatment duration. Antibiotics used to treat routine UTIs include trimethoprim-sulfamethoxazole (TMP-SMZ), ampicillin, cephalosporins, fluoroquinolones, and nitrofurantoin. Most infections respond to three-day antibiotic courses of TMP-SMZ, a fluoroquinolone, or nitrofurantoin (Buttaro et al., 2011). Criteria for antibiotic selection for treatment of urinary tract infections (UTIs) include type of urinary tract infection (acute uncomplicated, complicated, recurrent), microorganism susceptibility (culture and sensitivity), likelihood of bacterial resistance, adequate antimicrobial concentration achieved in urine, toxicity, and anticipated side effects (Buttaro et al., 2011). TMP-SMZ (Bactrim) is a widely used combination antibiotic consisting of sulfamethoxazole and trimethoprim which interferes with folate synthesis. Sulfamethoxazole inhibits bacterial folic acid synthesis and growth through the blockage of dihydrofolic acid synthesis from para-aminobenzoic acid. Trimethoprim prevents dihydrofolic acid reduction to tetrahydrofolate causing inhibition of enzymes needed for the folic acid pathway (Lexi-Comp, 2016). TMP-SMZ (Bactrim) is bacteriolytic and inexpensive; therefore, it is considered the antibiotic of choice for N.M., who is suffering from acute uncomplicated UTI. Bacterial eradication and cure rates are higher than 85% to 90. Three day antimicrobial regimens have been shown to give the same cure rate as traditional 7 to 10 day courses in at least 90% of women (Buttaro et al., 2011). It is recommended that a double strength tablet, 160 mg trimethoprim–800 mg sulfamethoxazole, be administered every 12 hours for 3-5 days for uncomplicated UTI. As a result, the course of treatment for N.M. will consist of one tablet of 160 mg trimethoprim–800 mg sulfamethoxazole twice daily for three days. It is vital to discuss the importance of taking the antibiotics as prescribed to ensure effectiveness (Lexi-Comp, 2016). Possible side effects of TMP-SMZ to consider for this patient include fever, rash, pruritus, photosensitivity, neutropenia, thrombocytopenia, anorexia, nausea and vomiting, and Stevens-Johnson syndrome. It is essential to discuss potential side effects so the patient is aware of potential effects, how to respond if such effects occur, and when to notify the provider.
The use of TMP-SMZ has been associated with embryo-fetal toxicity; therefore, N.M. should receive a pregnancy test prior to initiating therapy. Additionally, a culture and sensitivity, CBC, serum potassium, creatinine, and BUN should be obtained prior to initiating therapy (Lexi-Comp, 2016). TMP-SMZ may induce drug interactions with common medications including angiotensin-converting-enzyme inhibitors (ACE inhibitors), angiotensin II receptor blockers (ARBs), antidiabetic agents, carvedilol, and phenytoin. These interactions must be considered when prescribing TMP-SMZ. Currently, N.M. is not prescribed other medications, so that is not a concern at this moment (Lexi-Comp, 2016).