泌尿系统感染Urinarytractinfection.ppt

Urinary Tract InfectionsUrinary Tract InfectionsUTI UTI-common affliction for which patients seek medical attention UTI can occur from infancy through old age more common in females than males 20%of all females will experience a UTI during their lifetimeUTIDefinitionsThe term“UTI”represents a wide range of clinical syndromes Bacteriuria:the presence of bacteria in urine -does not necessarily imply infection Asymptomatic bacteriuria:presence of bacteria in the urinary tract in the absence of symptoms -clinical significance controversial outside certain patient populations -pregnant women -patients undergoing invasive procedures of the urinary tract UTIDefinitions Cystitis:UTI presumed to be confined to the bladder -painful/burning urination -urgency or frequency -absence of symptoms or physical signs suggesting inflammation at other sites within the urinary tract Note:clinical criteria are notoriously inaccurate in identifying the actual anatomic site of infectionUTIDefinitions Pyelonephritis:clinical diagnosis which implies a more invasive infection-inflammation of the kidney and renal pelvis is assumed to be present when patients have pain or tenderness involving the flank,together with other clinical or laboratory evidence of UTI-fever,nausea,chills,malaise,headache,etcUTIDefinitions Prostatitis:inflammation/infection of the prostate gland -may present as acute or chronic Intrarenal abscess/perinephric abscess:collection of pus in the kidney or in the soft tissue surrounding the kidneyUTIDefinitions Complicated infections -underlying abnormality that predisposes patient to UTI or makes UTI more difficult to treat effectively Recurrent Infections Relapse-recurrence of infection by same organism after discontinuation of treatment Reinfection-recurrence of infection by a different organism after discontinuation of treatmentUTIPathogenesis UTI usually due to patients own intestinal flora -ascending route of infection -organisms enter the urinary tract in a retrograde fashion via the urethra Complicating factors such as catheters,nephrostomy tubes,surgery,urinary stones,etc -allow organisms to enter and persist in urinary tract -alter the typical spectrum of organisms -may have multiple etiologiesUTIPathogenesis Elderly patients -incontinant -functionally impaired -postmenopausal changes -neurological alterations Pregnant women -altered anatomy Hematogenous route -endocarditis,bacteremias,tuberculosis -disseminated infectionsUTIEtiology Majority of UTI are due to a single pathogen The Enterobacteriaceae responsible for 90%of all UTI-gram negative bacilli-facultatively anaerobic-common intestinal floraEscherichia coli most commonly isolated pathogen 80%of all UTI Community-Acquired UTIE.coliK.pneumoniaeProteusS.saprophyticusS.epi&gm-entericsEnterococcusUro-pathogens E.coli,Klebsiella spp.-intrinsic gut organisms-highly motile-produce fimbriae(pili)attachment Proteus,Morganella,Providencia-Urease producing organisms-increases urinary pH-leads to crystal formation biofilmscolonization of catheterprotects bacteria from host defenses&antibioticsNosocomial UTIcatheter associatedShort TermLong TermE.coliE.coliPseudomonasPseudomonasProteusProteusEnterobacterCandidaProvidenciaMorganellaS.aureusEnterococcusUrinalysis usually have increased numbers of WBC leukocyte esterase test is often positive nitrate test is often positiveUrinalysis Urine culture:significant bacteriuria usually defined as 105 bacteria/ml.(108/litre)lower numbers may be significant in children and in catheter collected specimensSpecimen collection Should all patients with a suspected UTI be cultured?Community acquired vs nosocomial?Should all isolates be identified?Susceptibility testing?Specimen collection Clean catch mid stream specimensClean catch mid stream specimens -most frequently used method -urethra cleaned prior to collection -first void urine allowed to pass to clear urethra -mid-stream collected in sterile container Collection bags(children)Collection bags(children)-used in young children lacking bladder control -often contaminated -most meaningful result is a negative cultureSpecimen collection Suprapubic aspiration/straight cathetersSuprapubic aspiration/straight catheters -invasive -specimen obtained directly from bladder Indwelling cathetersIndwelling catheters -urine obtained by inserting needle into catheter or through diaphram -preferable to obtain specimen from new catheter,rather than old catheterSpecimen transport Sent to and processed by lab as quickly as possible-Require:method of collection time of collection patients antibiotics Specimens not received by lab in 1-2 hours MUSTMUST be refridgerated Urines not received within 24 hours or not refridgerated will be rejected by laboratoryAntimicrobial Therapy Empiric Therapy -based on most probable pathogens -local rates of resistance -acute infection vs chronic -reinfection or relapse -indwelling catheter etcManagement of UTIAnatomical/Functional Predisposition to UTI Impaired bla