Enterococcus faecalis Tropism for the Kidneys in the Urinary Tract of C57BL/6J Mice

P. mirabilis produces mannose-resistant Proteus-like (MR/P) pili, which are CUP pili that facilitate biofilm formation and colonization of the bladder and kidneys, and are crucial for catheter-associated biofilm formation

Enterococcus 2%

Gram Stain of Escherichia coli

Treatment for Uncomplicated UTIs UTIs in low-risk women can often be successfully treated over the phone. In such cases, a health professional provides the patients with 3-day antibiotic regimens without requiring an office urine test. This course is recommended only for women at low risk for recurrent infection, who do not have symptoms (such as vaginitis) suggesting other problems. Antibiotic Regimen . Oral antibiotic treatment cures 94% of uncomplicated urinary tract infections, although the rate of recurrence remains high. The following antibiotics are commonly used for uncomplicated UTIs: The standard regimen has traditionally been a 3-day course of trimethoprim-sulfamethoxazole, commonly called TMP-SMX (Bactrim, Cotrim, Septra). TMP-SMX combines an antibiotic with a sulfa drug. A single dose of TMP-SMX is sometimes prescribed in mild cases, but cure rates are generally lower than with 3-day regimens. Allergies to sulfa are common and may be serious. Fluoroquinolone antibiotics, also called quinolones, have usually been a second choice. However, in geographic areas that have a high resistance to TMP-SMX, quinolones are now the first-line treatment for UTIs. Ciprofloxacin (Cipro) is the quinolone antibiotic most commonly prescribed. Quinolones are usually given over a 3-day period. Pregnant women should not take these drugs. Nitrofurantoin (Furadantin, Macrodantin) is a third option. This drug must be given for longer than 3 days. Fosfomycin (Monurol) is not as effective as other antibiotics but may be used during pregnancy. Resistance rates to this drug are very low. Other antibiotics may also be used, including amoxicillin (with or without clavulanate) and cephalosporins. Doxycycline is often effective but cannot be given to children or pregnant women.

Symptoms of lower urinary tract infections usually begin suddenly and may include one or more of the following signs:

Vesicoureteral Reflux (VUR). Vesicoureteral reflux (VUR) affects about 10% of all children and is the cause of up to 50% of urinary tract infections during childhood.

Benign prostatic hyperplasia (BPH), enlargement of the prostate gland, can produce obstruction in the urinary tract and increase the risk for infection.

Specific Risk Factors in Women

Escherichia (E.) coli is responsible for most uncomplicated cystitis cases in women, especially in younger women. E. coli is generally a harmless microorganism originating in the intestines. If it spreads to the vaginal opening, it may invade and colonize the bladder, causing an infection. The spread of E. coli to the vaginal opening most commonly occurs when women or girls wipe themselves from back to front after urinating, or after sexual activity. Staphylococcus saprophyticus accounts for 5 - 15% of UTIs, mostly in younger women. Klebsiella , Enterococci bacteria, and Proteus mirabilis account for most of remaining bacterial organisms that cause UTIs. They are generally found in UTIs in older women. Rare bacterial causes of UTIs include ureaplasma urealyticum and Mycoplasma hominis , which are generally harmless organisms. Organisms in Severe or Complicated Infections The bacteria that cause kidney infections ( pyelonephritis ) are generally the same bacteria that cause cystitis. There is some evidence, however, the E. coli strains in pyelonephritis are more virulent (able to spread and cause illness). Complicated UTIs that are related to physical or structural conditions are apt to be caused by a wider range of organism. E. coli is still the most common organism, but others include Klebsiella , P. mirabilis , and Citrobacter . Fungal organisms, such as Candida specie s. ( Candida albicans causes the "yeast infections" that also occur in the mouth, digestive tract, and vagina.) Other bacteria associated with complicated or severe infection include Pseudomonas aeruginosa , Enterobacter, and Serratia species, gram-positive organisms (including Enterococcus species), and S. saprophyticus .

About 25 - 50% of these women can expect another infection within a year of the previous one. Between 3 - 5% of women have ongoing, recurrent urinary tract infections, which follow the resolution of a previous treated or untreated episode.

Recurrences occur in up to 50 - 60% of patients with complicated UTI if the underlying structural or anatomical abnormalities are not corrected.

95% of cases of UTIs are caused by bacteria that typically multiply at the opening of the urethra and travel up to the bladder. Much less often, bacteria spread to the kidney from the bloodstream

UTIs are the most common of all bacterial infections and can occur at any time in the life of an individual.

Treatments and drugs

Tests and diagnosis

Complications

Risk factorsBy Mayo Clinic Staff

Causes

Bacterial Urinary Tract Infections (UTIs)