Urinary infection is the name given to the infection of any structure of the urinary tract, including urethra, bladder, ureters or kidneys. In more than 95% of the patients the infection is of bacterial origin, being the bacterium Escherichia coli responsible for more than 3/4 of these cases.
There is no single treatment that works for all forms of urinary tract infection. The most indicated drug will depend on the causative agent, the sex of the patient, the site of the urinary tract affected, the severity of the disease and the clinical condition of the patient.
Cystitis is the name given to bladder infection, being the simplest and most common form of urinary tract infection. Cystitis occurs primarily in women, being uncommon in healthy men.
Let us divide the explanation of the treatment of cystitis into 5 groups:
Bladder infection that occurs in women without health problems is called uncomplicated cystitis. This is the most common type of urinary tract infection.
The vast majority of cases of uncomplicated cystitis are caused by E.coli, but other bacteria, such as Proteus mirabilis, Klebsiella pneumoniae and Staphylococcus saprophyticus can also be the cause. Therefore, the treatment of uncomplicated cystitis in women should always include an antibiotic that has an action against these bacteria, especially on E.coli, responsible for more than 80% of the cases.
The choice of antibiotic is made more correctly when based on the results of urine culture, a urine test used to identify which bacteria are causing the infection. In the result of the uroculture, besides the identification of the bacterium, the laboratory also provides a list with the antibiotics that invitro were shown more effective to fight it. This list is called antibiogram. Therefore, when the doctor has access to the result of the uroculture, the choice of antibiotic should always be based on the antibiogram.
It should be noted that most of the time cystitis is a simple and easily treated infection, and there is no need to request uroculture for all cases. The result of the uroculture takes 2 to 4 days to be ready, which would delay the start of treatment and the relief of symptoms within several days. In general, because the symptoms are very typical, on suspicion of uncomplicated cystitis in women, the doctor is authorized to start antibiotics empirically without asking for any examination.
The most commonly used remedies against cystitis are antibiotics that act on bacteria that usually cause urinary tract infection, especially against E. coli bacteria . The best empirical treatment options (without antibiogram orientation) include:
Nitrofurantoin 100 mg 12/12 for 5 to 7 days.
Trimethoprim-sulfamethoxazole (Bactrim) 160/800 mg 12/12 hours for 3 days.
Fosfomycin 3 g in a single dose.
Levofloxacin 250 mg to 500 mg once daily for 3 days.
Ciprofloxacin 250 to 500 mg 12/12 hours for 3 days.
Norfloxacin 400 mg 12/12 hours for 3 days.
Amoxicillin + clavulanate 500 mg 12/12 hours for 5 to 7 days (pure amoxicillin, without clavulanic acid is not very effective for treating cystitis).
The choice of the best treatment depends on the knowledge of the sensitivity profile of E.coli in each community. There are localities, for example, where the resistance rate of E.coli to Bactrim is known to be high, and this is not a good option for empirical treatment.
Pyridium (Phenazopyridine) or Cystex are not effective antibiotics and therefore are not used to treat urinary tract infection. These drugs are only analgesics, serving only to temporarily alleviate the symptoms of urinary burning, without having effective action on the bacteria.
WARNING: Do not use this text to self-medicate. Indicating antibiotics is the doctor's job. The wrong choice can cause serious side effects and create resistant bacteria.
Complicated cystitis is bladder infection that occurs in women with some health problem that increases the risk of treatment failure. Complicated cystitis is generally considered to occur in patients with:
Kidney transplantation or other causes of immunosuppression
Patients with complicated cystitis should always collect urine tests, especially uroculture. It is not necessary to wait for the results of the exams to begin antibiotic treatment, but having an antibiogram and the bacterium that causes the urinary tract infection identified within 2 or 3 days helps a lot to decide the next step if the patient has not improved in the first 72 hours of empirical treatment. In general, we suggest that the patient go to the laboratory to have a urine test and then start antibiotics.
The best empirical treatment options (without antibiogram orientation) for complicated cystitis include:
Levofloxacin 500 to 750 mg 1x per day for 5 to 14 days, depending on the severity of the case.
Ciprofloxacin 500 mg 12/12 hours for 5 to 14 days, depending on the severity of the case.
If the patient does not show signs of improvement within 2 or 3 days, the antibiotic should be changed according to the antibiogram, which should be available by this time.
In cases of patients with kidney stones or urinary tract obstructions, surgical removal of these stones may be necessary for successful treatment. Similarly, patients with a bladder catheter or stent in the ureter may have to swap them to get rid of the urinary tract infection. The bacteria can lodge in any of these structures and be able to "hide" from the antibiotic, being very difficult to eliminate only with medicines.
Approximately 2% of pregnant women have at least one episode of cystitis during pregnancy. The risk of ascending bacteria from the bladder to the kidneys is greater in pregnant women, causing all cystitis in this group to be considered a complicated cystitis. In addition, the presence of bacteria in the urine is associated with problems in pregnancy, such as preterm birth, low fetal weight and fetal death.
Due to the risk of fetal malformations, not all antibiotics can be used in pregnant women. Therefore, pregnant women deserve a different approach than other patients with complicated cystitis.
All pregnant women with symptoms suggestive of cystitis should harvest uroculture and begin empiric antibiotic treatment. The best options are:
Nitrofurantoin 100 mg 12/12 hours for 5 to 7 days
Cefpodoxime 100 mg 12/12 hours for 3 to 7 days
Amoxicillin-clavulanate 500 mg 12/12 hours for 3 to 7 days
Fosfomycin 3 g in a single dose
Cephalexin 500 mg 12/12 hours for 3-7 days
Trimethoprim-sulfamethoxazole (Bactrim) 160/800 mg 12/12 hours for 3 days is an option, but only from the second trimester, and should be avoided within the first 12 weeks of pregnancy. Quinolone antibiotics such as ciprofloxacin, norfloxacin and levofloxacin are contraindicated in pregnancy.
One week after the end of treatment, the uroculture should be repeated to confirm the elimination of the bacteria. If the uroculture is again positive for the same bacterium, the treatment should be repeated, this time for a longer time.
On the other hand, if the uroculture confirms the elimination of the bacteria, it must be repeated every month until the end of gestation, to make sure that there will be no new infections.
Cystitis is a much less common picture in men than in women due to the longer length of the urethra, the less moist periurethral environment, the lower colonization of bacteria in the region around the urethra, and the presence of antibacterial substances in the prostatic fluid.
Usually, cystitis in males occurs in those with abnormalities of the urinary tract, such as malformations in young children or urological diseases in elderly patients, such as prostate problems. However, uncomplicated cystitis can occur in a small number of men between the ages of 15 and 50 without any health problems.
All men with symptoms suggestive of cystitis should harvest uroculture and begin empiric antibiotic treatment. The best options are:
Trimethoprim-sulfamethoxazole (Bactrim) 160/800 mg of 12/12 hours for at least 7 days
Levofloxacin 500 mg once daily for at least 7 days
Ciprofloxacin 500 mg 12/12 hours for at least 7 days
If after 48-72 hours there is no improvement, the treatment should be adjusted according to the result of the uroculture and the antibiogram. In these cases, an investigation for changes in the urological anatomy should be
It should always be borne in mind that symptoms of urinary tract infection in men do not necessarily indicate cystitis, since prostatitis (such as prostatitis and treatment ) and urethritis, as in the case of gonorrhea, may have very similar symptoms.
Positive uroculture in patients without symptoms - asymptomatic bacteriuria
Cystitis is inflammation of the bladder caused by bacteria. The mere presence of bacteria in the urine without signs of bladder inflammation is not considered an infection, but a colonization. An easy to understand analogy is with the skin. Having bacteria present on the skin is completely different from having a skin infection. Therefore, the mere presence of bacteria in the urine is not sufficient for the diagnosis of an infection. To be cystitis it is necessary that the patient has symptoms of an inflamed bladder, such as pain to urinate, blood in the urine, constant urge to urinate, even with empty bladder, etc.
Even in E. coli bacteria, there are less virulent strains that can proliferate in the urine but lack the strength to cause inflammation of the bladder. A positive uroculture, even for E.coli, in a patient with no complaints, should not be valued in most cases. In fact, if the patient has no urinary complaints, it does not make sense to request uroculture.
The presence of bacteria in the urine without symptoms is called asymptomatic bacteriuria and should not be treated with antibiotics in the vast majority of cases. The only exceptions are the pregnant women and the patients who will undergo urological surgeries. In these cases it is indicated the performance of uroculture, even without symptoms, and the treatment according to the result of the antibiogram. In all other cases, the treatment of asymptomatic bacteriuria has no benefits and may further stimulate the development of resistant bacteria.