What Are the Different Urinary Tract Infection Causes?

Urinary tract infection, also known as urinary tract infection, is an inflammatory reaction of urinary tract epithelium to bacterial invasion, usually accompanied by bacteriuria and pyuria.

Basic Information

nickname

Urinary system infection

English name

urinary tract infection, UTI

Visiting department

Urology

Common causes

More than 95% are caused by a single bacterium

Common symptoms

Frequent urination, urgency, dysuria, bladder or perineal discomfort and burning urethra

Contagious

no

Urinary tract infection is divided into upper urinary tract infection and lower urinary tract infection according to the infection site; according to the relationship between the two infections, it can be divided into isolated or sporadic infection and recurrent infection, and the latter can be divided into reinfection and bacterial persistence. Existence, the continued existence of bacteria is also called relapse; according to the urinary tract status at the time of infection, it can be divided into simple urinary tract infection, complex urinary tract infection, and uremia. Urinary tract infections often occur in women, especially in active sexual life and postmenopausal women.

Causes of urinary tract infections

More than 95% of urinary tract infections are caused by a single bacterium. Among them, 90% of outpatients and about 50% of inpatients, the pathogenic bacteria is Escherichia coli, the serotype of this bacterium can reach 140 species, causing urinary susceptible Escherichia coli and the large intestine Escherichia coli isolated from the patient's stool. The genus Bacillus belongs to the same type of bacteria, which is more common in asymptomatic bacteriuria or uncomplicated urinary sensation; Proteus, Aerobacter, Klebsiella pneumoniae, Pseudomonas aeruginosa, Streptococcus faecalis, etc. are found in reinfection and indwelling Urinary tract and urinary tract infections with complications; Candida albicans and new cryptococcus infections are more common in patients with diabetes and glucocorticoids and immunosuppressive drugs and after kidney transplantation; Staphylococcus aureus is more common in skin trauma and drug users Bacteremia and septicemia caused; Viruses and mycoplasma infections, although rare, have been increasing in recent years. A variety of bacterial infections are found in indwelling urinary catheters, neurogenic bladder, stones, congenital malformations and vagina, intestinal and urethral fistulas.

Clinical manifestations of urinary tract infection

Acute simple cystitis

Sudden onset, female patients are mostly related to sexual activity. The main manifestations are bladder irritation, that is, frequent urination, urgency, pain, urinary bladder or perineal discomfort, and burning sensation in the urinary tract; urinary frequency varies, and severe urinary incontinence can occur in severe cases; cloudy urine, white blood cells in urine End-hematuria is common, sometimes full hematuria, and even blood clots are seen. Generally no obvious symptoms of systemic infection, normal temperature or low fever.

2. Acute simple pyelonephritis

(1) Symptoms of the urinary system include urinary bladder irritation such as frequent urination, urgency, dysuria; hematuria; ipsilateral or bilateral low back pain; obvious tenderness or throbbing pain in the ribs and corners of the affected side;

(2) Symptoms of systemic infections such as chills, high fever, headache, nausea, vomiting, loss of appetite, etc., are often accompanied by increased white blood cell counts and increased erythrocyte sedimentation.

3. Asymptomatic bacteriuria

Asymptomatic bacteriuria is an occult urinary tract infection. It is more common in elderly women and pregnant women. Patients do not have any symptoms of urinary tract infection, and the incidence increases with age.

4. Complex urinary tract infection

The clinical manifestations of complex urinary tract infections vary widely, often with other diseases that increase the risk of acquiring infection or treatment failure, with or without clinical symptoms (such as frequent urination, urgency, dysuria, dysuria, back pain, Spine rib tenderness, pain and fever in the suprapubic area, etc.). Complex urinary tract infections are often accompanied by other diseases, such as diabetes and renal failure; they also cause more sequelae. The most severe and fatal conditions include uremia sepsis and renal failure. Renal failure can be divided into acute and chronic , Reversible and irreversible.

Diagnosis of urinary tract infection

1. Medical history collection

(1) Clinical manifestations of symptoms, duration, and accompanying symptoms of urinary tract infections;

(2) Searching for possible causes, concomitant diseases, previous drug treatment history, and factors that may affect the development and outcome of the disease, such as past history, drug history and related disease history ;

2. Physical examination

Includes examination of extra-urinary genitals; physical examination of the abdomen and kidney area. Digital pelvic and rectal examinations are useful for identifying whether other diseases are combined.

3. Auxiliary inspection

(1) Laboratory tests include blood routine, urine routine, urine smear microscopy, middle-stage urine bacterial culture + drug sensitivity, blood bacterial culture + drug sensitivity, renal function tests, etc .;

(2) Imaging examination includes ultrasound, plain abdominal film, intravenous pyelography, etc. CT or MRI can be selected if necessary.

Urinary Tract Infections Treatment

1. Female non-pregnancy urinary tract infection

(1) Three-day therapy is recommended for the treatment of acute simple cystitis , that is, oral compound sulfamethoxazole; or ofloxacin; or levofloxacin. Because single-dose therapy is not as effective as three-day therapy, it is no longer recommended. For areas where the resistance of pathogenic bacteria to sulfamethoxazole is as high as 10% to 20%, furantoin can be used for treatment.

(2) The treatment of acute simple pyelonephritis is recommended to be treated with antibiotics for 14 days, and the course of highly effective antibiotics for patients with mild acute pyelonephritis can be shortened to 7 days. For mild symptoms, oral quinolone drugs can be used. If the pathogenic bacteria are sensitive to the compound sulfamethoxazole, this drug can also be taken orally. If the pathogen is a Gram-positive bacterium, it can be treated with amoxicillin or amoxicillin / potassium clavulanate alone. For severe cases or those who cannot take oral medication, they should be hospitalized and treated intravenously with quinolone drugs or broad-spectrum cephalosporin antibiotics. For those who are resistant to -lactam antibiotics and quinolone antibiotics, aztreonam can be used; The bacterium is Gram-positive cocci, which can be treated with ampicillin / sulbactam sodium, and can be used in combination if necessary. If the condition improves, refer to the urine culture results and choose sensitive antibiotics for oral treatment. It is important to adjust the plan and follow-up during the medication period. Urine culture should be performed every 1 to 2 weeks to observe whether the urine bacteria are negative. Quantitative culture of urine bacteria should be performed at the end of the treatment course and at the 2nd and 6th weeks after discontinuation of the drug, and it is best to review it once a month in the future.

(3) Complex urinary tract infections. The treatment options for complex urinary tract infections depend on the severity of the disease. In addition to antibacterial treatments, anatomical dysfunction of the urinary system and other underlying diseases combined must be treated at the same time, and nutritional support treatment if necessary. If the condition is severe, hospitalization is usually required. First of all, basic diseases such as diabetes and urinary tract infarction should be controlled in a timely and effective manner. If necessary, it should be treated together with relevant professional doctors such as endocrinology department. Otherwise, it is difficult to cure the disease with antibiotics alone. Secondly, broad spectrum antibiotics are used intravenously based on experience. During the medication period, the treatment plan should be adjusted in time according to the changes in the condition and / or the results of the bacterial drug sensitivity test. Some patients still need to use the combination medication for a period of at least 10 to 14 days.

2. Male cystitis

All men with cystitis should exclude prostatitis. For non-complicated acute cystitis, oral compound sulfamethoxazole or quinolones can be used at the same dosage as for female patients, but the course of treatment requires 7 days. For patients with complicated acute cystitis, ciprofloxacin or levofloxacin can be administered orally. , Continuous treatment for 7 to 14 days.

3. Urinary tract infection during pregnancy

(1) Asymptomatic bacteriuria The incidence of asymptomatic bacteriuria during pregnancy is as high as 4% to 7%, which often occurs in the first month of pregnancy, and up to 40% of cases can progress to acute pyelonephritis, so it is recommended that Urine culture tests should be performed routinely on pregnant women in order to detect asymptomatic bacteriuria patients in a timely manner. It is currently recommended that anti-infective treatment should be taken for such patients. Antibiotics are recommended for 3-5 days based on the results of drug sensitivity tests. One of the following options can be used: furantoin; amoxicillin; amoxicillin / clavulanate. Patients are requested to come to the hospital to review the urine culture at 1 week after the drug is stopped, and then to review it monthly afterwards until the end of pregnancy. For those with recurrent asymptomatic bacteriuria, antibiotic precautions can be taken during pregnancy, and furantoin or cephalexin should be taken every night before bedtime.

(2) Acute cystitis is recommended to be treated with antibacterial drugs for 3 to 5 days based on the results of urine culture and drug sensitivity tests. If it is too late to wait for the results of the drug sensitivity tests, furanotoin, or amoxicillin, or the second and third generation cephalosporins . After treatment, a urine culture examination is needed to understand the treatment effect. If recurrent episodes of acute cystitis are recommended daily oral cefuroxime or furantoin until bedtime to prevent recurrence.

(3) Acute pyelonephritis The incidence of acute pyelonephritis during pregnancy ranges from 1% to 4%, mostly in the third trimester. It is recommended to first give an intravenous infusion of antibacterial drugs based on the results of urine culture or blood culture and drug sensitivity tests. If you are too late to wait for the results of the drug sensitivity tests, you can choose ceftriaxone, aztreonam, or piperacillin + tazobactam, or Cefepime, or ampicillin. After clinical symptoms have improved significantly, oral antibiotics can be used instead. The total course of treatment is at least 14 days.

4. Asymptomatic bacteriuria

Antimicrobial therapy is not recommended for premenopausal non-pregnant women, diabetic patients, the elderly, patients with spinal cord injury and asymptomatic bacteriuria with indwelling catheters. However, patients with asymptomatic bacterial urine who undergo transurethral prostate surgery or other urological procedures or examinations that may cause urinary tract mucosal bleeding should be treated with sensitive antibiotics based on bacterial culture results.

5. Catheter-related urinary tract infection

(1) Most asymptomatic bacteriuria is not recommended for antibiotic treatment. Some exceptions recommend appropriate treatment: nosocomial infections caused by more virulent microorganisms; patients who may be at risk of severe concurrent infections; patients with urinary system surgery; infections with certain strains that can cause high rates of bacteremia; and age Larger female patients may require short-term treatment after removal of the catheter.

(2) For symptomatic infection, it is recommended to replace the catheter that has been indwelled for more than 7 days before taking urine samples for culture and antibacterial treatment, or to use other methods such as penile drainage, suprapubic cystostomy drainage, etc .; if not necessary Those who continue to place can no longer intubate. It is recommended to choose effective antibiotics based on the results of urine culture and drug sensitivity tests. Initially, broad-spectrum antibiotic treatment can be selected based on experience, and then antibiotic use can be adjusted based on the culture results. Less severe symptoms can be taken orally, usually for 5-7 days. Those with severe symptoms, fever, positive blood culture, and difficulty in gastrointestinal administration can choose parenteral administration, such as intramuscular or intravenous injection. In severe cases, medication is usually 10 to 14 days. Occasionally candida infections can be treated with antifungals. Long-term, unfounded antibiotic use is not recommended.