ADULT UTI URINARY TRACT IN ADULTS

Urinary tract infection in adults is common and may be complicated or uncomplicated.

Infection of the urinary tract (UTI) is frequently encountered in clinical practice — in the USA these account for approximately 7 million office visits annu- ally. The reported incidence in women is 11% per year and approximately 50% of all women have at least one UTI in their lifetime.1,2 UTI accounts for 40% of nosocomial infections and catheter use is the leading cause.3 Up to 25% of hos- pitalised patients undergo catheterisation and the incidence of is 5% per day.4

Symptomatic UTI exists when clinical symptoms are attributable to bacteria in the normally sterile urinary tract. Symptoms vary depending on the site of infection (lower or upper tract). • Uncomplicated UTI describes infection where the urinary tract is entirely nor- ELIZABETH COETZER mal. MB ChB, FCP (SA) • Complicated UTI occurs where the urinary tract is compromised, either struc- Specialist Physician turally, functionally, metabolically or immunologically. Pretoria East Hospital Asymptomatic UTI is identified when organisms can be isolated in appropriate numbers from urine in the absence of symptoms. Elizna Coetzer graduated at the University of Pretoria and did her internship at Adult patients with UTI can be categorised according to different clinical syn- Boksburg-Benoni Hospital. She was dromes (Fig. 1). Medical Registrar in the Department of 1,5 Medicine at Groote Schuur Hospital from DEFINITIONS AND DIAGNOSTIC TESTS 1998 to 2001. She completed 2 years at Bacterial invasion of the urinary tract causes an inflammatory response resulting the UCT Renal Unit and is currently a spe- in bacteriuria and pyuria. Indirect dipstick tests and/or direct microscopy of cialist physician in private practice at urine should be performed in all patients suspected of having a UTI.

Pretoria East Hospital. Indirect dipstick tests Dipstick nitrite is used as a surrogate marker for bacteriuria. Infection due to uropathogens which do not reduce nitrate to nitrite (e.g. Gram-positive cocci) may be responsible for false-negative results.

The dipstick leukocyte esterase test is a rapid, convenient and cheap screening tool for detecting pyuria.

However, neither is diagnostic of significant bacteriuria, and urine microscopy and culture are required for confirmation.

Microscopic urinalysis and culture Pyuria is the presence of white blood cells (WBC) in the urine and is indicative of urothelial inflammation. This is a nonspecific finding, but the vast majority of symptomatic patients have pyuria. In a random clean-catch urine specimen ≥10 WBC/mm3 will be consistent with infection. WBC casts in the presence of symp- toms is strong evidence for . Sterile pyuria warrants investigations for other conditions such as , calculi or urinary tract malignancy.

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urological reasons, or those with an altered sensorium. In non-infect- Cystitis (lower tract) / Pyelonephritis (upper tract) ed patients samples obtained in this manner are less likely to be contaminated enough to demon- strate 105 organisms/ml. With ASYMPTOMATIC careful technique numbers as low as 102 organisms/ml are highly SYMPTOMATIC indicative of infection. • Suprapubic aspiration is particular- ly useful in adults with paraplegia. UNCOMPLICATED This invasive procedure is unpleas- ant for the patient but, when per- formed properly, is not dangerous. RECURRENT Bladder urine obtained this way is either sterile or contains significant growth, even if bacterial numbers COMPLICATED are < 105/ml. Associated factors5 ¥ Structural abnormality/obstruction PATHOGENESIS Prostatic hypertrophy, bladder divertic- uli, genital prolapse Urinary tract invasion occurs in differ- Ureteric obstruction (strictures, pelvical- ent ways: iceal junction) • Ascending. Most pathogens are Renal cyst Urolithiasis intestinal, and enter the urinary tract through the urethra into the ¥ Functional bladder. In women vaginal coloni- Neurogenic bladder Vesico-ureteral reflux sation is an important factor. Once Foreign bodies/catheters (urethral in the bladder, bacteria may multi- catheter, nephrostomy tube, ureteral stent) ply and ascend via the ureters to Pregnancy the renal pelvis and parenchyma. ¥ Immuno-metabolic • Haematogenous. This is uncom- Diabetes mellitus mon in normal individuals, but Renal transplantation Cystic kidney disease, nephrocalcinosis blood-borne organisms can infect Renal failure the kidneys in patients with staphy- HIV infection (with CD4 counts < 200/mm3) lococcal bacteraemia from infective endocarditis or infected oral sites. Fig. 1. Classification of UTI. Secondary renal infection has also been described with Candida fun- Bacteriuria is the presence of bacteria Collecting urine specimens gaemia. in normally sterile urine. It implies that • The clean-catch method is preferred micro-organisms are from the urinary for routine collection, as it avoids Once colonisation and invasion has tract and not contaminants from the the risk of infection associated with taken place, host-parasite interaction distal urethra, vagina or skin. invasive methods. With proper col- becomes important in the development Bacteriuria without pyuria indicates lection voided urine usually con- of UTI. Strong host resistance needs to bacterial colonisation rather than tains < 104 organisms/ml. In be overcome by increased bacterial infection. Significant bacteriuria is asymptomatic patients 104 - 105 virulence factors. Conversely, less viru- ≥ 5 defined as 10 organisms/ml of organisms/ml represents contami- lent bacteria are able to infect patients voided urine (i.e. the number of bacte- nation 95% of the time. In patients who are compromised. Normal anti- ria that exceed the number usually due with symptoms of UTI, a titre of bacterial defences of the urinary sys- to urethral contamination).The possibil- ≥ 105 organisms/ml carries a 95% tem include high osmolality, low pH ity of contamination is inversely pro- probability of true bacteriuria and and presence of organic acids in portional to the reliability of the collec- even counts as low as 102 organ- urine, urine flow and micturition, spe- tion technique. Acceptable collection isms/ml confirm the diagnosis. cific inhibitors of bacterial adhesion, methods include: • Catheterisation performed under the inflammatory response (neu- • segmented voided urine specimens scrupulous aseptic technique may trophils, cytokines) and the immune or midstream clean catch be necessary in those who are system. • catheterisation unable to void for neurological or • suprapubic aspiration.

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CLINICAL SYNDROMES — In healthy adult men between the ages are only found in about 20% of MICROBIOLOGY, of 15 and 50 years, cystitis is very patients. Major differential diagnoses MANIFESTATIONS, AND uncommon and uncomplicated are outlined in Table I. MANAGEMENT pyelonephritis hardly ever occurs. In men, cystitis presents with irritative Uncomplicated UTI Uncomplicated cystitis voiding symptoms, but in some A relatively narrow spectrum of In women, sexual intercourse, patients may mimic urethritis. Major uropathogens cause UTI in patients diaphragm and/or spermicide use, differential diagnoses are outlined in with normal urinary tracts. Escherichia delayed postcoital micturition and a Table II. coli is the main organism isolated, fol- history of a recent UTI all increase the lowed by Staphylococcus saprophyti- risk of infection. In postmenopausal In women, uncomplicated cystitis cus. Enterococci and other Gram-nega- women, oestrogen deficiency with rarely progresses to symptomatic tive enterobacteriaceae such as atrophic vaginitis, and less abundant upper UTI, and does not have long- Klebsiella, Enterobacter and Proteus protective lactobacilli is another con- term negative effects with respect to 1,2,5 species infrequently cause infection in tributing factor. Reasons for infec- renal function or mortality. The this group.6 tion in men are not always clear, but causative organisms are predictable, risk factors include intercourse with an as are their antimicrobial susceptibility Acute cystitis and uncomplicated infected partner, anal intercourse and profiles. This means that women gener- 2 pyelonephritis are common problems lack of circumcision. ally require only an abbreviated in women, particularly sexually active workup and empirical therapy. women from 20 - 40 years of age, Cystitis is typically diagnosed clinical- Uncomplicated cystitis rarely occurs in and in the postmenopausal popula- ly. In women, symptoms include men, so pre-treatment urine culture is tion. dysuria with frequency and urgency, recommended and clinicians should but no fever or constitutional symp- have a low threshold for urology refer- toms. Suprapubic pain and tenderness ral and investigation.

Table I. Differential diagnosis of uncomplicated cystitis in women

Condition Clinical findings in addition to dysuria and pyuria Common aetiology

Urethritis or Urethral/vaginal discharge containing numerous WBCs Sexually transmitted infections vaginitis No suprapubic pain/tenderness, urinary frequency/ (STIs): Chlamydia trachomatis, urgency and fever Neisseria gonorrhoeae, Trichomonas vaginalis Cervicitis Irritative voiding symptoms with mucopurulent vaginal or STIs cervical discharge (containing numerous WBCs) and postcoital bleeding Cervical erythema and/or oedema with swabbing-induced bleeding Pelvic As for cervicitis with additional fever, cervical excitation STIs inflammatory tenderness ± evidence of tubo-ovarian mass E. coli, enteric Gram-negative rods, disease anaerobes, Streptococcus agalactiae and Mycoplasma and Ureaplasma spp.

Table II. Differential diagnosis of uncomplicated cystitis in men

Condition Clinical findings in addition to dysuria and pyuria Common aetiology

Urethritis Urethral discharge present STIs: C. trachomatis, No suprapubic pain, urinary frequency/urgency or fever N. gonorrhoeae Acute prostatitis Back pain, fever, arthralgia/myalgia, rectal pain and E. coli, Proteus spp., obstructive voiding symptoms Klebsiella spp. Tender, boggy prostate on examination Acute Fever and scrotal swelling + redness STIs or uropathogens (E. coli epididymitis Epididymal tenderness in patients with recent urinary tract instrumentation)

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The reported incidence in course of . Recurrent cystitis in women women is 11% per year •Drug allergy and specific contra- About 20% of young women with nor- and approximately 50% of indications. Quinolone should not mal urinary tracts have recurrent UTI be used in pregnancy. all women have at least within 6 months of an initial episode of cystitis.2 Over 90% of recurrences one UTI in their lifetime. Uncomplicated (non- are due to reinfection — this occurs obstructive community- after 2 weeks of completing acquired) pyelonephritis Dipstick nitrite is used as a treatment and may be caused by the In women, this infection is similar to same or a different organism. surrogate marker for bac- cystitis and is caused by similar bacte- Occasionally the original uropathogen teriuria. Infection due to ria. The clinical spectrum ranges from persists and causes recurrence within uropathogens which do not a cystitis-like illness with mild flank 2 weeks — this defines a relapse reduce nitrate to nitrite pain and fever or rigors, to a more infection. severe syndrome of urosepsis or Gram- (e.g. Gram-positive cocci) negative septicaemia.1,2,5 may be responsible for In addition to behaviour, host genetic factors and bacterial factors contribute false-negative results. Urine microscopy establishes the pre- to recurrence. sumptive diagnosis. Pyuria is present

and WBC casts may be seen. Pre- 1,2,7 The diagnosis can be presumed if Prophylaxis is indicated for women treatment urine culture and sensitivity pyuria is present on leukocyte esterase who experience at least 2 sympto- tests should be obtained in all patients dipstick testing or microscopy. The matic UTIs in less than 6 months. with suspected pyelonephritis, and finding of bacteriuria on microscopy is Eradication of active infection should blood culture should be taken in hospi- more specific but less sensitive.1 be confirmed by negative culture at talised patients (15 - 20% are posi- least 1 - 2 weeks after discontinuation tive). In selecting an antibiotic for treatment7-9 of initial treatment. The choice of pro- Clinical severity will dictate treatment several factors should be considered: phylactic regimen should be based on and further investigations:8-10 • Local microbial resistance patterns susceptibility of bacteria isolated from • Patients with mild illness can safely — resistance to β-lactam antibiotics prior UTI, drug allergies and intoler- receive oral treatment as outpa- (amoxicillin or ampicillin) and ance. tients with a quinolone or amoxi- trimethoprim-sulfamethoxazole has cillin- or 2nd gener- become widespread. Using these Effective measures decrease recur- ation cephalosporin for 10 - 14 drugs as first-line agents will give rences by up to 95% and may prevent days. low cure rates and is not recom- pyelonephritis. These measures • Those with moderate-to-severe ill- mended. include: ness or patients with nausea or • Duration of therapy with known • Continuous prophylaxis — an vomiting should be hospitalised for efficacy for the clinical syndrome, antibiotic is taken daily for at least initial parenteral treatment with versus cost and adverse effects — 6 months. It has been safely and quinolone or ceftriaxone or amino- short courses of empirical antibiotic effectively continued for longer glycoside ± ampicillin. With therapy are highly effective and without emergence of microbial improvement or resolution of the cost-efficient in the treatment of resistance. clinical picture after 48 - 72 hours, uncomplicated cystitis in women. • Postcoital prophylaxis — in women the remaining treatment can be Most antimicrobials can be used who describe a clear relation given orally. Fever and flank pain for 3 days, with efficacy compara- between intercourse and UTI, a sin- persisting beyond 72 hours of ther- ble with longer regimens and fewer gle dose of an antimicrobial is apy warrant further investigation: side-effects and lower cost. Single- taken with each act of coitus. urine cultures should be repeated dose therapy can be used, but may Another convenient, safe and inexpen- and the urinary tract imaged (ultra- result in lower cure rates and more sive strategy is intermittent patient-initi- sonography or computed tomogra- 1 frequent recurrences. Current guide- ated treatment. phy) to exclude abscess formation, lines for empiric treatment advocate •Women are instructed to start a 3- obstruction or unrecognised urologi- a 3-day course of oral quinolone or day course of an antibiotic agent cal abnormalities. Antibiotics amoxicillin-clavulanic acid/2nd at symptom onset. They are should be changed according to generation cephalosporin. advised to seek medical attention if susceptibility profiles of isolated Alternatively, a single dose of there is no resolution by 48 - 72 bacteria. either a quinolone or fosfomycin hours after completion of treatment. • Post-treatment urine culture is can be prescribed. Men who pres- preferable. ent with uncomplicated cystitis Additional corrective measures: should be treated with a 7-day • Atrophic vaginitis should be treated

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with topical oestrogen cream in bacteriuria often occur. A common Treatment must be tailored to individ- postmenopausal women. feature is an inability to effectively ual patient circumstances. Previous •Women exposed to spermicides clear organisms from the urinary tract bacteriological test results, severity of from diaphragms or condoms (obstruction) or an increased frequen- illness and allergy history need to be should consider alternative methods cy of introduction of bacteria into the considered. of contraception. urinary tract (instrumentation or reflux). •Oral fluoroquinolones provide a • There is no evidence that recurrent A high frequency of recurrent infection broad spectrum of antimicrobial cystitis can be prevented by post- is anticipated. If correction is possible, activity and should be given for at coital voiding. Poor urinary further infection may be prevented. least 7 days to patients with mild- hygiene does not predispose to to-moderate illness who can be recurrent UTI and there is no ration- Complications of treated as outpatients. 2,12 ale in giving specific instructions pyelonephritis • More seriously ill patients should regarding voiding, wiping patterns, • Emphysematous pyelonephritis (EP) be hospitalised and empirical par- douching or wearing of pantyhose.1 is an acute necrotising renal enteral broad-spectrum antibiotics parenchymal infection with given. Preferred antimicrobials are Cranberry juice7 has been long advo- intrarenal ± perinephric gas forma- quinolones or ceftriaxone or amino- cated as a measure to reduce the tion, primarily seen in diabetics. glycoside ± ampicillin or recurrence rate. Constituent glycopro- Delayed diagnosis adds to high piperacillin-tazobactam (suspected teins and proanthocyanidins appear to morbidity and mortality. enterococcal UTI). Therapy should inhibit bacterial adherence to uro- • Intrarenal abscesses are most com- be modified when the infecting epithelium. Randomised trials suggest- monly due to Staphylococcus organism has been identified and ed a daily dose of 200 - 750 ml juice aureus infection with 30 - 50% of susceptibilities are known. to reduce recurrence by 12 - 20%. patients having concomitant dia- Treatment duration is usually 10 - Variable therapeutic effect can be betes mellitus. 14 days, but Pseudomonas and ascribed to variations in actual cran- • Acute papillary necrosis is pre- enterococcal infections may war- berry content of juice, capsules or sumed to be due to marginal blood rant more prolonged therapy. tablets. supply which is further stressed by infection leading to infarction and UTI in patients with 5,6,12-14 Probiotic formulations7,11 containing papillary sloughing. Diagnosis is diabetes mellitus various lactobacilli and bifidobacteria confirmed on retrograde urogra- In diabetic women there is a 2 - 4-fold can also be used as adjunctive treat- phy. higher incidence of bacteriuria. ment. The primary aim of vaginal Contributing host factors include poor application of probiotic-containing Complicated UTI has a more diverse glycaemic control with impaired leuko- capsules is to restore the protective aetiology.5,6 Hosts with underlying dis- cyte function, recurrent vaginitis, microflora. Various studies have shown ease are susceptible to infection with anatomical and functional abnormali- that UTI recurrence can be significant- antimicrobial-resistant and/or unusual ties and microangiopathy. Most cases ly reduced by using probiotic capsules organisms and are at a higher risk for (80%) are due to ascending infection weekly for 1 year with similar efficacy treatment failure. with abovementioned uropathogens to continuous antibiotic prophylaxis and non-albicans Candida spp. and without side-effects. E. coli remains the commonest infect- Haematogenous spread of infection ing organism, but is isolated from only (mostly S. aureus) accounts for the Complicated UTI about 50% of patients. The remainder remainder of cases. Where there are underlying medical of isolates includes other enterobacteri- conditions, pregnancy, hospitalisation aceae (Klebsiella spp., Proteus spp.), Upper tract involvement occurs in up or long-term urinary catheter use, UTI Pseudomonas spp. and Gram-positives to 80% of diabetics with UTI, and (whether cystitis or pyelonephritis) (enterococci, coagulase-negative complications (emphysematous should be considered complicated. staphylococci and group B streptococ- pyelonephritis, abscess formation or The frequency and impact of compli- ci). papillary necrosis) also occur more cated UTI are determined by the frequently. Clinical presentation is simi- underlying abnormalities and compli- Pre-treatment culture (urine ± blood) is lar to that in non-diabetic patients cating factors may not be immediately mandatory in all patients. Urine cul- except that bilateral infection is more obvious.2,5 ture should be repeated 1 - 2 weeks common. Occasionally it may be after completion of therapy, as the asymptomatic, particularly in individu- The clinical spectrum ranges from mild recurrence rate is high (especially if als with metabolic disturbance or cystitis to life-threatening urosepsis. the underlying abnormality persists). reduced level of consciousness. Prolonged periods of asymptomatic Haematuria or flank pain may be

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Emphysematous amphotericin B bladder irrigation. urinary retention, and anticholinergic pyelonephritis (EP) is an Alternatively a single intravenous dose drugs), anatomical variations (genital acute necrotising renal of amphotericin B or oral fluconazole prolapse or prostate hypertrophy), can be prescribed. A poor response to hygiene issues (faecal soiling), neuro- parenchymal infection with therapy suggests complications: logical impairment affecting mobility, intrarenal ± perinephric emphysematous pyelonephritis often and voiding and hormonal changes. gas formation, primarily necessitates emergency nephrectomy seen in diabetics. and prompt surgical or percutaneous The frail elderly with multiple health drainage is required for intrarenal or problems and complicated UTI often perinephric abscesses. have an atypical or subtle presentation Fungal UTI is frequently (delirium, agitation, incontinence or 5,7,15 seen in diabetics and the UTI in pregnancy increased urine loss). Diagnosis is extent ranges from lower UTI is one of the most common infec- often delayed. Treatment should be tions of pregnancy. Bacteriuria occurs tract colonisation to clini- according to principles as outlined for in 5 - 9% of women — a significant complicated UTI and complicating or cal cystitis, pyelonephritis number of whom will develop sympto- contributing factors should be and abscess formation, and matic UTI during the course of the addressed. The best prophylaxis is to fungaemia. pregnancy. Most infections are caused minimise catheter use and to improve by E. coli and causative host factors general hygiene. are physiological changes (smooth- noted in patients with papillary necro- muscle relaxation with stasis, less In hospital or long-term care, sis and occasionally pneumaturia may robust humoral immune response) and indwelling catheters are the major be seen. mechanical factors (pressure on blad- cause of UTIs. Additional risk factors der with reflux). include increasing duration of Fungal UTI is frequently seen in diabet- catheterisation, no administration of ics and the extent ranges from lower The clinical entities include asympto- systemic antibiotics, female gender tract colonisation to clinical cystitis, matic bacteriuria (ASB), cystitis and and older age, rapidly fatal underly- pyelonephritis and abscess formation, pyelonephritis. Patients with untreated ing disease, diabetes mellitus and azo- and fungaemia. or inadequately treated ASB are at taemia as well as faulty aseptic man- high risk of developing pyelonephritis agement of catheter and/or collecting Investigation of possible UTI in diabet- which can lead to preterm labour, pre- system. ic patients should include urinalysis maturity and low-birth-weight infants. and culture prior to initiation of thera- Catheter-related bacteriuria is defined py, together with assessment of renal A urine culture should be obtained as the presence of ≥ 103 CFU/ml of a function and glycaemic status. In from all women in early pregnancy. predominant bacterial species and is patients with presumed pyelonephritis, Therapeutic options for treatment of usually asymptomatic, uncomplicated a blood culture should be routine. UTI are guided by pathogen suscepti- and resolves after catheter removal. It bility and antibiotic safety profile in is however associated with increased Imaging is essential owing to the high pregnancy (beta-lactams, nitrofuran- morbidity and mortality. incidence of complications. All toin). patients should have an abdominal • ASB should be treated with a 3- The following should be kept in mind X-ray to exclude renal emphysema. day course of antimicrobials. with regard to catheterisation: Severely ill patients should have • Symptomatic UTI should be treated •Avoid using catheters whenever screening ultrasound or computed for 7 days. possible. tomography to exclude obstruction • Once UTI is documented, monthly • Appropriate indications for catheter and identify calculi and inflamed screening urine cultures should be use: bladder outlet obstruction, oedematous parenchyma. Contrast obtained for the duration of the incontinence (with open sacral or enables a more accurate recognition pregnancy. perineal wounds; on request at end of inflamed renal tissue, air or pus col- • Recurrent or persistent UTI may of life), output monitoring in critical- lection, but its use may be complicat- warrant daily antimicrobial prophy- ly ill patients, and during pro- ed by transient or permanent loss of laxis and urological evaluation. longed surgical procedures. renal function. •A closed catheter drainage system UTI in geriatric and should be used and proper aseptic Treatment for bacterial UTI includes institutionalised or techniques during insertion and 2-6 hydration, glycaemic control and non- catheterised patients maintenance must be adhered to. nephrotoxic parenteral antibiotics. Predisposing factors for development • There is little evidence to suggest Fungal UTI should be treated with of UTI in the elderly patient include benefit with bladder irrigation, removal of catheters if present and altered elimination (faecal impaction,

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antimicrobial drugs in drainage Table III. Incidence of asymptomatic bacteriuria in different bags or rigorous meatal cleaning. patient groups Prophylactic systemic antibiotics are most useful in patients requiring catheterisation for 3 - 14 days and Patient group Incidence the benefit of systemic antibiotic Non-pregnant and pregnant women 5 - 9% prophylaxis is proven in patients Community-dwelling elders (≥ 65 years) undergoing surgery and requiring • Women 20 - 25% indwelling catheterisation (renal • Men 5 - 10% transplantation or transurethral Patients in long-term-care facilities resection of the prostate). • Without catheters ± 40% • More research is needed to evalu- • With catheters Nearly 100% ate the benefit of silver-coated catheters. IN A NUTSHELL ASYMPTOMATIC UTI is a commonly encountered prob- in pregnancy and asymptomatic bac- BACTERIURIA lem in clinical practice, particularly teriuria should be treated aggressive- ASB2,5 is the presence of ≥ 105 organ- in women. ly. isms/ml of urine on at least 2 succes- Symptomatic UTI includes lower or Investigation and treatment of UTI sive cultures in patients without UTI upper tract involvement (cystitis or should be individualised according symptoms. Incidence increases with pyelonephritis). to the clinical setting in which it age (Table III). occurs. UTIs that occur in the setting of There appears to be a higher frequen- underlying medical conditions, preg- Dipstick tests are cheap, fast and cy of infection with coagulase-negative nancy or long-term use of a catheter convenient screening tools in patients staphylococci and Enterococcus spp. are considered to be complicated. with uncomplicated cystitis. Urine cul- tures should be performed in patients The incidence of asymptomatic bac- In healthy non-pregnant women, men with complicating factors and blood teriuria increases with age. However, and the well elderly ASB poses no cultures may be positive in up to it poses no threat in healthy non- threat, as symptomatic infection with 20% of patients with upper tract pregnant women, men and the well complications rarely develops. involvement. elderly. Screening should be limited Screening is useful only where treat- to selected patient groups where Factors that should be taken into con- ment is mandatory, as in the following treatment is mandatory (pregnancy, sideration in selecting an antibiotic situations:2,5,9 prior to urinary tract instrumentation, for treatment are: local microbial sus- • individuals with ASB undergoing and renal transplantation). ceptibility patterns, duration of thera- urological procedures are at risk of py with known efficacy for the clini- invasive infection (including bacter- UTI in the diabetic, elderly or debili- cal syndrome versus cost and aemia and ) tated patient may lack classic presen- adverse effects and patient factors • patients with renal allografts in the tation. (allergy and specific contraindica- early post-transplant period Complications of upper tract infection tions) as well as clinical severity. • ASB in pregnant women, if left are emphysematous pyelonephritis, untreated, may progress to sympto- Antibiotic prophylaxis is indicated for abscess formation, papillary necrosis matic infection (especially women who experience at least 2 and bacteraemia. These are particu- pyelonephritis) which is 4-fold high- symptomatic UTIs in less than 6 larly prevalent in patients with dia- er than in non-pregnant women. months. Alternative strategies are betes mellitus. intermittent patient-initiated treatment, References available on request. Pregnant women with UTI are at risk correction of biological or behaviour- of preterm labour, prematurity and al factors and use of probiotics and low-birth-weight infants — they cranberry extracts. should undergo urine screening early

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