brazjinfectdis2017;21(3):361–364
w w w . e l s e v i e r . c o m / l o c a t e / b j i d
The
Brazilian
Journal
of
INFECTIOUS
DISEASES
Letter
to
the
Editor
Ureteral
stent
infections:
a
prospective
study
夽
DearEditor,
Urinarytractinfectionisoneofthemostfrequentlyseen infec-tionsinthecommunityandalsoinhospitals.Itcanbeseen inabroadclinicalspectrumrangingfromasymptomatic bac-teriuriatoacutepyelonephritisaccompaniedwithsepsis.One oftheseclinicalconditionsisinfectionoftheurinarysystem withfunctionalorstructuralabnormalities.Ifcomplicated uri-narytractinfectionisconsidered,pre-treatmenturineculture shouldbetakeninordertodefinethecausativepathogenand antibioticsusceptibilitypattern.Renal damage,bacteremia, sepsisandincreasedmortalityaremorelikelyinthisgroupof patients.Fixingthecomplicatingfactorisequallyimportant asantimicrobialtreatment.Thepresenceofureteralstentis alsoapredisposingfactorforurinarytractinfection.
Inrecentyears,theuseofureteralstentshasincreasedin urologypracticeinordertoprovidedrainageofurine.Ureteral stentsleadtotheformationofforeignbodiessuchasbiofilms. Studies haverevealed thatbiofilms formedby microorgan-ismsare responsible forapproximately 65% of nosocomial infections,whichincreasetreatmentcostssignificantly.Asthe useofureteralstentincreased,theincidenceofcomplicated urinarytractinfection,whichisoneofthecomplicationsof ureteralstent,alsoincreased.1
Theaimofthisstudywastodeterminethefrequencyof infectionandasymptomaticbacteriuriaandcomorbidfactors associatedwiththedevelopmentofurinarytractinfectionin theadultpatientswithuretericstent.
Between the dates August 2008 and January 2011 the patientswhoplacedureteralstentinourUrologyDepartment wereevaluated.Sixty patientsaged18yearsandmoreand withsterileurinewhoagreedtoparticipateinthestudywere askedtosignaninformedconsentform.Afterureteralstent wasplacedthepatientsweremonitored0–30day,31–90day, 91–150day,151–210,>210daysintervals.Theassociationof urinarytractinfectionduringthetreatmentandpatients’age, sex,underlyingillnesses,reasonsforureteralstentplacement, lengthofstentplacementwereanalyzed.
Patientswithureteralstentswererecommendedtocome to the hospital immediately in case of dysuria, fever, and
夽ThemanuscriptwaspresentedasaposterinKL˙IM˙IK2013andICAAC2013.
sidepainthroughoutthefollow-upperiod.Thepatientswith elevated white-bloodcell(WBC), erythrocytesedimentation rate (ESR) and CRP valueswho had complaints ofdysuria, fever,sidepainandhadatleast10leukocyte/mm3andgrowth 105CFU/mlbacteriainmidstreamcleancatchurinewere diag-nosedasurinarytractinfection.
Duringthefollow-upperiod,thepatientswhoseWBC,ESR andCRPvalueswerenormalandwhodidnothaveany com-plaintsofdysuria,fever,sidepain,but developedthesame strainofbacteriainthequantitativeculturetechniqueoftwo differentcleancatchsampleofurineas105CFU/mlwere diag-nosedasasymptomaticbacteriuria.
ThedatacollectedwerestoredinSPSS13.0package pro-gramforstatisticalanalysis.Studentttestandchi-squaretest wereused.Statisticalsignificancelevelwasfixedatp<0.05.
Sixty patients with ureteral stent were followed up prospectively during the study until ureteral stent was removed.Themainfeaturesofthesepatientsareshownin Table1.Ofthepatientsincludedinthestudy,33(55%)were female and27(45%)were male.Patients’ agesrangedfrom 20to86,mean49.1±16.1.Themeandurationoftheureteral stentinplacewas128±77days,rangingfrom26to334days, onaverage,median111days.
Themainreasonforplacingureteralstentwasprophylactic beforeextracorporealshockwavelithotripsy(ESWL),followed byhydronephrosisduetonephrolithiasisandureteralstenosis ofunknowncause.
Themostcommonriskfactorsforurinaryinfectionwere diabetesmellitusandchronicrenalfailure.Theassociationof riskfactorswithurinarytractinfectionisshowninTable2.
Eleven (18%) patients developed urinary tract infection. Longer duration ofureteral stentinplace,presenceof dia-betes mellitus, and presenceof chronic renal failure were significantlyassociatedwiththedevelopmentofurinarytract infection.
Outofthe11patientswhodevelopedurinarytractinfection sixhadtheirureteralstentchangedandweregivenantibiotics accordingtothesusceptibilitytestresults.Theremainingfive patientswhodevelopedurinarytractinfectionweretreated withappropriateantibiotics,buttheureteralstentswereleft
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braz j infect dis.2017;21(3):361–364Table1–Characteristicsofthepatients. Demographiccharacteristics Age(years) Mean(min–max) 49.1(20–86) Gender(n%) Female 33(55) Male 27(45)
Durationureteralstent(days)
Mean(min–max) 128(26–334)
Reasonsofplacingureteralstent(n%)
ProphylacticbeforeESWL 26(44)
Hydronephrosisduetonephrolithiasis 17(28)
Othera 17(28)
ESWL,extracorporealshockwavelithotripsy.
a Ureteralstenosisofunknowncause,ureteralobstructiondueto genitourinarymalignancy,ureteralobstructiondueto retroperi-toneal fibrosis, ureteral obstruction due to gastrointestinal malignancy,ureteralobstructionduetopregnancy.
inplace.Infivepatientsurinarytractinfectionrelapsedafter 24daysonaverage.
Eleven(18%)patientsdevelopedasymptomaticbacteriuria. Ofthose,threepatientsdevelopedurinarytractinfectionina periodrangingfrom14to45days,averageof27days.
Overall,22microorganismswererecoveredfromurine cul-tures,11fromthepatientswithurinarytractinfectionand11 frompatientswithasymptomaticbacteriuria.Amongpatients
withurinarytractinfectionwasEscherichiacoliwasthemost commonlyisolatedmicroorganismamongbothpatientswith urinary tract infection (45%) and with asymptomatic bac-teriuria (64%). The distribution of microorganisms isolated fromurineculturesofpatientswithurinarytractinfectionor asymptomaticbacteriuriaisshowninTable3.
All of the 22 bacteria isolated from urine cultures were sensitive to ertapenem, meropenem, and imipenem. Extended-spectrumbeta-lactamase(ESBL)wasdetectedin7 (58.3%)outof11E.colistrainsisolatedfromurinarytract infec-tions.
Ureteralstentshavebeenwidelyusedinurologypractice inthe lasttwo decadesinparallel withincreasingnumber ofendourologicinitiatives.Ureteralstentsmayleadto bac-terialcolonizationsimilarlytoallinsertedsyntheticmedical devices.Astheuseofureteralstentsincreased,theincidence ofcomplicated urinary tract infection,which isone ofthe complicationsofureteralstent,hasalsoincreased.
Inastudyinvestigatingthecolonizationinureteralstents, colonizationwasalreadydetectedinsomestentsafteroneday ofinsertion,butcolonizationhaddisappearedatthetimeof stentremoval38daysthereafter.Colonizationdependsonage, gender, comorbidity,andimmunological status.2 Inastudy
ofFarsietal.,colonizationvariedaccordingtothepolymer characteristicofthestent;theyreportedbacterialcolonization of67.9%,andbacteriuriaprevalenceof29.9%.3Inthisstudy
theoccurrenceofasymptomaticbacteriuriaandurinarytract infectionwereinvestigatedseparately.Asymptomatic bacteri-uriaandurinarytractinfectionwerediagnosedin18%.The
Table2–Theassociationofriskfactorswiththedevelopmentofurinarytractinfection. Patientswith urinarytract infection Patientswithout urinarytract infection p-value (n=11) (n=49) Agerange 18–33 0 12 34–49 4 14 >0.05 50–64 4 16 ≥65 3 7 Gender Male 6 21 Female 5 28 >0.05
Meanofdurationureteralstent(days) 206 110 0.03
Comorbidfactors
Diabetesmellitus 5 3 0.01
Hypertension 2 3 >0.05
Chronicrenalfailure 3 2 0.03
Malignancy 3 3 >0.05
Nephrolithiasis 7 36 >0.05
Indicationsforureteralstent
ProphylacticbeforeESWL 1 25
Hydronephrosisduetonephrolithiasis 6 11
Ureteralstenosisofunknowncause 1 6 >0.05
Ureteralobstructionduetomalignancy 3 3
Ureteralobstructionduetoretroperitonealfibrosis 0 2
Ureteralobstructionduetopregnancy 0 2
brazj infect dis.2017;21(3):361–364
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Table3–Microorganismsisolatedfromurineculturesofpatientsdiagnosedwithurinarytractinfectionorasymptomatic bacteriuria.
Microorganisms Urinarytractinfection Asymptomaticbacteriuria
n(%) n(%) Escherichiacoli 5(45) 7(64) Enterococcusspp. 3(28) Candidaalbicans 1(9) 1(9) Klebsiellapneumoniae 1(9) 1(9) Pseudomonasaeruginosa 1(9) 1(9)
CoagulasenegativeStaphylococcus 1(9)
lowerrateofasymptomaticbacteriuriacomparedtoanother studycouldbepossiblyattributedtoreasonssuchasplacing ureteralstentinelectiveconditions,havinglesscomorbid dis-eases,andusingthestentinthesamepolymercharacteristic ineachpatient.
Theperiodthe ureteralstent remained inplacewas 75
days on average in the study made by Mohammed et al.
andinanother study itwas 52days.4 Thetimeofureteral
stent remained inplace has been shown to bea risk fac-torforthe bacterialcolonization.Inour study,theaverage time with ureteral stent was 128 days. This period was foundtobelongercomparedtootherstudies.Inourstudy, similarly,prolonged time withureteral stent increasedthe possibility of urinary tract infection increased(p=0.03). In the majority of the patients who developed urinary tract infection, ureteral stent remained in place for more than 150days.
Astudy byAkay et al. investigatedrisk factors for uri-narytract infection and stent colonization in190 patients withureteralstents.Inthis study,independentriskfactors forthedevelopmentofurinarytractinfectionwerediabetes mellitus,chronicrenalfailure,andpregnancy.5Inourstudy,
urinarytractinfectionwasalsomorecommoninthepatients withureteralstentswhowerediagnosedwithdiabetes mel-litus and chronic renal failure (p=0.01). Diabetes mellitus and chronic renal failure can be predisposing factors for thedevelopmentofinfectionbycompromisingtheimmune system.
Urinary tract infection relapsed in five patients treated accordingtoantibioticsusceptibilitytestresultsafter24days ofdetectingurinarytractinfection.Thisfindingcould have beenduetothelackofeffectivenessofantibioticson bacte-rialcolonizationoftheureteralstent.Inouropinionureteral stentsofthepatientswithurinarytractinfectionshouldbe replacedafterappropriateantibiotictreatment.
Urinary tract infection was detected in three patients whoseureteralstentsremainedinplaceafterasymptomatic bacteriuriaafteranaverageof27 days.Asymptomatic bac-teriuriashouldbeconsideredasanindicatorofbiofilm.Inthis groupofpatientsiftheindicationofureteralstentuseremains andasymptomaticbacteriuriaisdetected,replacingthestent isthoughttobeanappropriateapproachsoastopreventthe developmentofurinarytractinfection.
Inourstudy,E.coliwasthemostcommonlyisolatedamong patientswithurinarytractinfections(45%),andinthosewith asymptomatic bacteriuria (64%). Despite the low number ofcases inour study, in12 E. colistrains evaluated, there were 58% extended-spectrum beta-lactamase (ESBL), 67%
trimethoprim/sulfamethoxazole resistant,58% ciprofloxacin resistant, 58% ceftriaxone resistant. The high positivity rate of ESBL, as well high resistance rates for trimetho-prim/sulfamethoxazole, ciprofloxacin, and ceftriaxone may be dueto inserting the stent inthe hospitalenvironment, and stent presence resulting in complicated urinary tract infections.
Antibioticorbactericidecoatedstentsareontheagenda intherecentyearsinordertopreventbacterialcolonization. However,despitetheadvancestoday,theidealstentthatdoes notcauseany complicationshasnotbeen producedsofar. Ourstudywaspotentiallylimitedbyitsobservationaldesign and smallsamplesize.Despitetheselimitations,ourstudy presents a picture of infection and asymptomatic bacteri-uriaandcomorbidfactorsassociatedwiththedevelopment ofurinarytractinfectionintheadultpatientswithureteric stent. Therefore it is thought as an appropriate approach that the patients with ureteral stent should be informed about the symptoms ofurinary tract infection and should beclosely followedup soastominimize complications.In particular, wethink that patients diagnosed with diabetes mellitus, chronicrenal failure, or those who need ureteral stent for a long time should come to the hospital imme-diately when symptoms like dysuria, side pain, or fever occurs.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
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1.TenkeP,KövesB,NagyK,etal.Updateonbiofilminfectionsin theurinarytract.WorldJUrol.2012;30:51–7.
2.RiedlCR,PlasE,HübnerWA,ZimmerlH,UlrichW,PflügerH. Bacterialcolonizationofureteralstents.EurUrol.1999;36:53–9. 3.FarsiHMA,MosliHA,Al-ZemaityMF,BahnassyAA,AlvarezM.
Bacteriuriaandcolonizationofdouble-pigtailureteralstents: longtermexperiencewith237patients.JEndourol.
1995;9:469–72.
4.Al-GhazoMA,GhalayiniIF,MataniYS,El-RadaidehKM, HaddadHI.Theriskofbacteriuriaanduretericstent colonizationinimmune-compromisedpatientswithdoubleJ stentinsertion.IntUrolNephrol.2010;42:343–7.
5.AkayAF,AflayU,GedikA.Riskfactorsforlowerurinarytract infectionandbacterialstentcolonizationinpatientswitha doubleJureteralstent.IntUrolNephrol.2007;39:95–8.
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braz j infect dis.2017;21(3):361–364NilsunAltunala,∗,AyseWillkea, OnurHamzao ˘glub
aKocaeliUniversityMedicalFaculty,DepartmentofInfectious
Dis-easesandClinicalMicrobiology, ˙Izmit,Kocaeli,
Turkey
bKocaeliUniversityMedicalFaculty,DepartmentofPublicHealth,
˙Izmit,Kocaeli,Turkey
∗Correspondingauthor.
E-mailaddress:[email protected] (N.Altunal).
Received22November2016 Accepted12December2016 Availableonline9February2017 1413-8670/
©2017SociedadeBrasileiradeInfectologia.Publishedby ElsevierEditoraLtda.Thisisanopenaccessarticleunderthe CCBY-NC-NDlicense(http://creativecommons.org/licenses/ by-nc-nd/4.0/).
