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1、Urinary Tract InfectionWu YitaiDepartment of NephrologyTongji Hospital,Tongji University,Content,DefinitionsEpidemiologyEtiologyPathogenesis PathologyClinical presentation DiagnosisTreatmentsComplicationPrevention,Definition of UTI,UTI is defined as the presence of micro-organisms in the urinary tra
2、ct.Most patients with UTI have significant bacteriuria,i.e.bacterial colony counts 105/ml,in a mid-stream“clean catch”urine.Conversely,colony counts 105/ml of midstream urine are occasionally due to specimen contamination.Acute urethral syndrome:dysuria,urgency,and frequency,but without bacteriuria.
3、,AnatomicLower UTI:urethritiscystitis(mucosal infection)Upper UTI:pyelonephritisprostatitisintrarenal and perinephric abscesses(tissue invasion),Classification of UTIs（1）,Classification of UTIs（2）,ClinicalUncomplicated UTI:Lack structural or functional abnormalities of the urinary tractNormal flow o
4、f urineNO interference with the normal defensesComplicated UTI:Predisposing lesion of the urinary tract,structural or functional abnormalities,e.g.congenital abnormality of the urinary tract,stone,obstruction,catheter.Interference with the normal defenses,e.g.immunosuppression,renal disease,or diabe
5、tes.,Classification of UTIs（3）,EpidemiologyCatheter-associated（nosocomial）infections:Symptomatic Asymptomtic Non Catheter-associated（community-acquired）infections:Symptomatic Asymptomtic,Epidemiology,Almost half of all women will have at least one UTI in their lives.UTI is uncommon in men under the
6、age of 50,but very common among women.Asymptomatic bacteriuria is more common among elderly men and women.,Etiology（1）,Community-Acquired UTIgram-negative bacilli is the most common agent,E.coli,Enterobacter,Enterococcus,Proteus,Staphylococcus,Klebsiella,E.coli,Etiology（2）,Causative organisms:Escher
7、ichia coli Klebsiella,proteus and pseudomonas 1-Bacteria S.aureus,Staphylococcus epidermidis and S.saprophyticus Enterococci(Streptococcus faecalis粪链球菌)Mycobacterium tuberculosis Chlamydia trachomatis,Neisseria gonorrhoeae 2-Virus Herpes simplex virus,HIV 3-Fungus Candida,Histoplasma capsulatum 4-Pr
8、otozoon Trichomonas vaginalis,Schistoma haematobium,CASE 1 32 year-old woman;Dysuria and frequency;Pyuria in the urine sediment;Gram negative bacilli.Escherichia coli(E.coli).,CASE 2 65 year-old woman;Dysuria and frequency;Pyuria;Gram positive cocci.Enterococcus faecalis,CASE 318 year-old woman Dysu
9、ria and frequency;Pyuria;Gram positive cocci;Staphylococcus.,CASE 4 42 year-old diabetic woman with a catheter.Gram positive yeasts.Candida grew.,Route of Infection,Ascending route(the most common),Colonization of urethra,Pathogenesis,Pathogenesis（1）,The urinary tract above the urethra is normally s
10、terile.The urethral meatus and surrounding perineum are colonized with a mixture of skin and bowel flora.Vaginal flora or pathogens may contaminate the urethra.,Pathogenesis（2）,Host defense mechanisms:1.Urine:low pH,high osmolality,high urea&organic acid concentration inhibit and kill microorganisms
11、2.Regular urine flow:dilute and expel pathogens3.Bladder epithelial cells:coated with mucus(glycosaminoglycan)prevent bacteria from adhering to bladder wall,Conditions affecting pathogenesis,Gender and sexual activity.Pregnancy.Obstruction.（tumor,stricture,stone,BPH）Neurogenic bladder dysfunction.Ve
12、sicoureteral refluxBacterial virulence factorsGenetic factors（details in the following）,Conditions affecting pathogenesis（1）,Gender and sexual activity The female urethra appears to be prone to colonization with colonic gram-negative bacilli because of its proximity to the anus,its short length,and
13、its termination beneath the labia.Voiding after intercourse reduces the risk of cystitis.An important factor predisposing to bacteriuria in men is urethral obstruction due to prostatic hypertrophy.,Conditions affecting pathogenesis（2）,PregnancyUTIs are detected in 2 to 8%of pregnant women.Pregnant w
14、omen with asymptomatic bacteriuria.Bladder catheterization during or after delivery causes additional infections.,Conditions affecting pathogenesis（3）,Obstruction TumorStrictureStoneBenign prostatic hypertrophy(BPH)These conditions result in hydronephrosis and increase frequency of UTI.,Conditions a
15、ffecting pathogenesis（4）,Neurogenic Bladder DysfunctionInterference with bladder enervation,as in spinal cord injury,multiple sclerosis,diabetes.The infection may be initiated by the use of catheters for bladder drainage.The infection is favored by the prolonged stasis of urine in the bladder.,Condi
16、tions affecting pathogenesis（5）,Vesicoureteral RefluxVesicoureteral reflux occurs during voiding or with elevation of pressure in the bladder.Common among children with anatomic abnormalities of the urinary tract.Renal damage correlates with marked reflux,not with infection.,Conditions affecting pat
17、hogenesis（6）,Bacterial Virulence factorsSpecific O,K,and H serogroups.Adherence of bacteria to uroepithelial cells is a critical first step in the initiation of infection.Fimbriae mediate the attachment of bacteria to specific receptors on epithelial cells.E.coli strains usually produce hemolysin an
18、d aerobactin.,Conditions affecting pathogenesis（7）,Genetic factorsHost genetic factors influence susceptibility to UTI.The number and type of receptors on uroepithelial cells are in part genetically determined.,Conditions affecting pathogenesis,Gender and sexual activity.Pregnancy.Obstruction.（tumor
19、,stricture,stone,BPH）Neurogenic Bladder Dysfunction.Vesicoureteral RefluxBacterial Virulence factorsGenetic factors,Pathology,Cystitis,Mucosal hyperemiaEdemaLeukocyte infiltrationEasy bleedingGranular surfaceSuperficial ulcerPurulent exudate,Pathology,Acute Pyelonephritis,Acute inflammationHyperemia
20、 and edemaVolume increase Red colour Yellowish abscess Purulent exudate,Pathology,Chronic Pyelonephritis,Chronic inflammationPelvis deformed Cortex scarsVolume shrink Asymmetric Parenchyma atrophy,Pathology,Interstitial edema Neutrophil infiltration White blood cell cast,In microscopy,Clinical Prese
21、ntation,Clinical presentation（1）,CystitisBurning painFrequency,urgencySuprapubic painDysuria,Clinical presentation（2）,Urethritis Burning painFrequency,urgencyDysuriaInfected with sexually transmitted pathogens,Clinical presentation（3）,Acute PyelonephritisAll cystitis symptoms（+）or（-）Fever,shaking ch
22、illsNausea,vomiting,diarrheaTachycardia,hypotentionMuscle tendernessCostovertebral angle（CVA）painGram-negative sepsis,LeukocytosisLeukocyte casts in the urine,Clinical presentation（4）,Catheter-Associated UTIs Bacteriuria develops in at least 10 to 15%of hospitalized patients with indwelling urethral
23、 catheters.The risk of infection is 3 to 5%per day of catheterization.Many infecting bacteria display markedly great antimicrobial resistance.,How is it diagnosed?,Diagnosis,Patient history Complete physical examination Urine culture Urine analysis Other examinations,Microscopic Examination,Pyuria W
24、BC 5/HP,Bacterial colony counts 105/ml,Diagnosis,DiagnosisDipstick Methods,Leukocyte esterase+Nitrite+,Urine routine:pH,sg,protein,glucose,blood,ket,etc.,Clean urine culture:bacterial counts 105/mlSuprapubic puncture,catheter collected urine 102/mlSignificant bacteriuria Microscopic bacteriuria,Urin
25、e Culture Test(very important),Diagnosis,Localization of UTI,（No definite standard method）,Ultrasonography Intravenous pyelography（IVP）Abdominal CT/MRI,Treatments for different types of UTIs,Acute uncomplicated cystitisPathogens,Staphylococcus saprophyticus(5-15%)Enterobacteriaceae E.coli(86%)Klebsi
26、ella pneumoniaeProteus Enterococcus,Single-dose therapy is less effectiveEspecially with-lactams3-day course recommendedTMP-SMX,fluoroquinolone,nitrofurantoinNOT appropriate for male patients and complicated UTIs7-day course:Diabetes,age 65 years,MalesIf untreated:may lead to acute uncomplicated pye
27、lonephritis treatment,Acute uncomplicated cystitisTreatment-Antibiotic Therapy,Acute uncomplicated pyelonephritisPathogens,EnterobacteriaceaeE.coli Klebsiella pneumoniaeProteus Staphylococcus saprophyticus,Mild or moderate symptoms:Outpatient treatment(714 days)Oral treatment:Fluoroquinolone,TMP/SMX
28、,third generation cephalosporinSevere ill patient:Hospitalization requiredParenteral therapy(14 days)Broad-spectrum cephalosporins or Fluoroquinolones,Acute uncomplicated pyelonephritisTreatment(714 days),Complicated UTIsPathogens,EnterobacteriaceaeE.Coli Klebsiella pneumoniaeProteusEnterococciPseud
29、omonasStaphylococci,Minimal or mild symptoms(10-14d).Oral therapy:fluoroquinolone(ciprofloxacin or ofloxacin)Severe ill patient,parenteral therapy(10-21d).Hospitalization required,Imipenem alone Penicillin or cephalosporin plus aminoglycoside Third generation cephalosporin:Ceftriaxone or ceftazidime
30、,Complicated UTIsTreatment,Low urinary tract infection(acute cystitis):7 days course antibiotics Amoxicillin,cephalosporine,nitrofurantoinPyelonephritis:2-4 weeks course antibiotics Cephalosporins,extended spectrum penicillins Parenteral treatment Follow-up urine culture tests,monthly Low-dose proph
31、ylaxis to recurrent infectionsAsymptimatic bacteriuria Antibiotics treatments are needed.,UTI in Pregnant womenTreatment,UTI in catheterized patientsTreatment,For bacteriuria in asymptomatic catheterized patient:Catheter removed as soon as possible.The bacteriuria should be ignored.If becomes sympto
32、matic:Remove catheterTreatment as described for complicated infectionsIf the catheter cannot be removed,antibiotic therapy usually proves to be unsuccessful.,Complications,Renal Papillary necrosisPatients with diabetes,sickle cell disease,chronic alcoholism,and vascular diseaseHematuria,pain in the
33、flank or abdomen,chills and feverAcute renal failure with oliguria or anuriaIVP:ring shadowOften bilateral,Prevention,Drink plenty of fluids and frequent urination.Keeping the perineal area clean.Do not take invasive method of examination if possible.Prophylactic low-dose antibiotics,daily or thrice-weekly administration of a single dose of TMP-SMX,TMP,nitrofurantoin,fluoroquinolone.Patient who suffer refluence of bladder-ureter should change the urination habit（twice urination，i.e.after urination for several minutes,to urinate again）,THANKS,
