Rev. bras. ortop. vol.51 número4

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rev bras ortop.2016;51(4):396–399

SOCIEDADE BRASILEIRA DE ORTOPEDIA E TRAUMATOLOGIA

w w w . r b o . o r g . b r

Original

Article

The

incidence

and

microbiological

profile

of

surgical

site

infections

following

internal

fixation

of

closed

and

open

fractures

夽

Priscila

Rosalba

Oliveira

∗

_,

_Vladimir

_Cordeiro

_Carvalho,

_Cassia

_da

_Silva

_Felix,

Adriana

Pereira

de

Paula,

Jorge

Santos-Silva,

Ana

Lucia

Lei

Munhoz

Lima

UniversidadedeSãoPaulo,HospitaldasClínicas,InstitutodeOrtopediaeTraumatologia,SãoPaulo,SP,Brazil

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e

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o

Articlehistory:

Received21August2015 Accepted9September2015 Availableonline2February2016

Keywords:

Surgicalwoundinfection Internalfracturefixation Openfractures

Closedfractures

a

b

s

t

r

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c

t

Objective:Toevaluatetheincidenceandmicrobiologicalprofileofsurgicalsiteinfections (SSIs)associatedwithinternalfixationoffracturesandtocomparedifferencesintheSSIs observedamongpatientswithclosedandopenfractures.

Methods:Retrospectivestudy.Analyzeddataincludedinformationfromallpatientswho underwentsurgeryforfixationofclosedoropenfracturesfromJanuary2005toDecember 2012andremainedoutpatientsforatleastoneyearfollowingsurgery.Incidenceofsurgical siteinfection(SSI)wascomparedbetweenpatientswithclosedandopeninfection,aswell aspolymicrobialinfectionandinfectionrelatedtoGram-negativebacilli(GNB).Cumulative antibiogramswereperformedtodescribemicrobiologicalprofiles.

Results:OverallincidenceofSSIwas6%.Thisincidencewassignificantlyhigheramong patientswith openfractures (14.7%) thanamongpatients withclosedfractures (4.2%). TheproportionsofpatientswithpolymicrobialinfectionsandinfectionsduetoGNBwere alsosignificantly higheramongpatients withopen fractures. Staphylococcusaureus and coagulase-negativeStaphylococcus(CoNS)speciesweretheprimaryinfectiousagents iso-latedfrombothgroups.TheoverallincidenceofMRSA(methicillin-resistantS.aureus)was 72%.A.baumanniiwasthepredominantGNBisolaterecoveredfrompatientswithopen frac-turesandP.aeruginosawasthemostfrequentisolaterecoveredfrompatientswithclosed fractures,bothexhibitedlowratesofsusceptibilitytocarbapenems.

Conclusions:IncidenceofSSIsrelatedtotheinternalfixationoffractureswassignificantly higheramongpatientswithopenfractures,indicatingthatanopenfracturecanbearisk factorforinfection.Amongthebacterialisolates,S.aureus(withahighprevalenceofMRSA) andCoNSspeciesweremostprevalent.A.baumanniiandP.aeruginosaisolatesunderscored thelowrateofsusceptibilitytocarbapenemsthatwasobservedinthepresentstudy.

夽

WorkdevelopedattheUniversidadedeSãoPaulo,HospitaldasClínicas,InstitutodeOrtopediaeTraumatologia,SãoPaulo,SP,Brazil. ∗ _{Corresponding}_author_.

E-mail:priscila.rosalba@hc.fm.usp.br(P.R.Oliveira).

http://dx.doi.org/10.1016/j.rboe.2015.09.012

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rev bras ortop.2016;51(4):396–399

397 Infecc¸ão

de

sítio

cirúrgico

após

fixac¸ão

de

fraturas

fechadas

e

expostas

–

Incidência

e

perfil

microbiológico

Palavras-chave:

Infecc¸ãodaferidaoperatória Fixac¸ãointernadefraturas Fraturasexpostas Fraturasfechadas

r

e

s

u

m

o

Objetivo:AvaliaraincidênciaeoperfilmicrobiológicodasISCrelacionadasaprocedimentos defixaçãodefraturasnumhospitalacadêmicoortopédicoterciárioemSãoPaulo,Brasil,e compararasdiferençasobservadasentreospacientescomfraturasfechadaseexpostas. Métodos: Estudoretrospectivo.Foramincluídosnaanáliseosdadosrelativosatodosos pacientesquepassaramporprocedimentocirúrgicoparafixaçãodefraturasfechadasou expostasdejaneirode2005adezembrode2012equemantiveramseguimentoporpelo menosumano.Foiverificadaapresençadeassociaçãoentreotipodefratura,aincidência deISCeasincidênciasdeinfecçõespolimicrobianaseporbacilosGram-negativos.Operfil microbiológicofoiestabelecidopormeiodaelaboraçãodeantibiogramascumulativos. Resultados: Aincidênciageraldeinfecçãode6%.Essaincidênciafoimaiornogrupode pacientescomfraturasexpostas(14,7%)doquenaquelescomfraturasfechadas(4,2%),com diferençaestatisticamentesignificante.Onúmerodepacientescominfecções polimicro-bianasecominfecçõesrelacionadasaBGNtambémfoisignificativamentemaiornogrupo decasosrelacionadosafraturasexpostas.StaphylococcusaureuseespéciesdeStaphylococcus coagulase-negativo(CoNS)foramosprincipaisagentesisoladosnosdoisgrupos.A incidên-ciadeMRSA(S.aureusresistenteameticilina)dentretodososisoladosdeS.aureusfoide 72%.A.baumanniifoioprincipalBGNisoladoentreospacientescomfraturasexpostase P.aeruginosaentreospacientescomfraturasfechadas.Emambososcasos,observaram-se baixosíndicesdesensibilidadeacarbapenêmicos.

Conclusões: AincidênciadeISCrelacionadaàfixac¸ãointernadefraturasfoi significante-mentemaiornospacientescomfraturasexpostas,oqueindicaqueessetipodefraturapode serumfatorderiscoparaaocorrênciadessetipodeinfecc¸ão.Dentreosisoladosbacterianos, predominaramnogeralS.aureus(comelevadaprevalênciadeMRSA)eS.coagulase-negativo. DentreosBGN,houvepredomíniodeA.baumannitambémentreosisoladosdepacientes comfraturasexpostaseP.aeruginosaentreosisoladosdaquelescomfraturasfechadas.

Introduction

Surgicalsiteinfections(SSIs)associatedwithinternalfixation offracturesareregardedasseriouscomplications.AnSSI con-stitutesachallengefortheentirestaffinvolvedinpatient’s carebecauseitsignificantlyincreasesrecoverytimeand treat-ment costs and negatively impacts bothfunctional results andlong-termrehabilitation.1,2_Although_incidence_of_SSIs_is expectedtobehigherinpatientswithopenfracturesthanin patientswithclosedfractures,fewstudieshaveconfirmedthis hypothesis.3,4 _Regarding_the_{microbiological}_profiles_of_SSIs, Gram-negativebacilli(GNB),mostnotablyAcinetobacter bau-mannii andPseudomonas aeruginosa,have been described as havingincreasinglyimportantrolesintheseinfections, par-ticularlyincasesinvolvinghigh-energytrauma.5–8

Thecurrentstudy soughtto evaluatethe incidenceand microbiologicalprofileofSSIsassociatedwithinternalfixation offracturesandtocomparedifferencesintheSSIsobserved amongpatientswithclosedandopenfractures.

Methods

AretrospectivestudywasconductedattheInstitutode Ortope-diaeTraumatologia,atertiaryorthopedicacademichospitalin

SãoPaulo,Brazil.Analyzeddataincludedinformationfromall patientswhounderwentsurgeryforfixationofclosedoropen fracturesfromJanuary2005toDecember2012andremained outpatientsforatleastoneyearfollowingsurgery.Thesedata werecollectedfromthedatabasemaintainedbythe institu-tion’sInfectionControlBoard.

Inaccordancewiththeinstitution’sprotocol,patientswith closedfractureswhounderwentsurgeryfortheinternal fix-ationoftheirfracturesreceived24hofantimicrobial prophy-laxiswithcefazolin.PatientswithtypeIopenfractures accord-ingtotheGustiloclassificationreceivedantimicrobialtherapy with cefazolin for 14 days, beginning at their admission. PatientswithopenfracturesofGustilotypesIIandIIIreceived combinationtherapywithclindamycinandgentamicinfor14 days,beginningatadmission.Inaddition,patientswithopen fractures initially had their fractures stabilized byexternal fixation;internalfixationwassubsequentlyperformedafter improvementinthesofttissueadjacenttofracture.

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rev bras ortop.2016;51(4):396–399

Table1–Patientpopulationofthestudy.

Total Closedfractures Openfractures Comparisonbetweenthegroups withclosedandopenfractures

Patients 11,030 9143 1887 –

PatientswithSSIs 664(6%) 386(4.2%) 278(14.7%) p<0.001 Patientswithpolymicrobialinfections 199(1.8%) 90(1%) 109(5.8%) p<0.001 PatientswithGNBinfections 293(2.65%) 130(1.42%) 163(8.64%) p<0.001

LaboratoryStandardInstitute(CLSI)standards.10_Only_isolates fromculturesofbone,deepsofttissueorexudatecollected intheoperating roomafterthe debridement ofdevitalized tissueswereconsidered.

Chi-squaretestswereusedtodeterminehowfracturetype wasassociatedwiththeincidencesofSSI,polymicrobial infec-tionsandGNBinfections.Theseassociationswereestimated by utilizing bivariate logistic regressions to calculate odds ratios(ORs)andthecorresponding95%confidenceintervals. Microbiological findings were only assessed by descriptive analysis.

Results

Duringtheanalyzedperiod,11,030patientsunderwent inter-nalfixationoffractures,including9143patients(82.9%)with closedfracturesand1887patients(17.1%)withopenfractures. Atotalof664patientspresentedwithSSIsrelatedtofixation procedures;thus,theoverallincidenceofinfection was6%. Thisincidencewassignificantlyhigheramongpatientswith openfractures(14.7%)thanamongpatientswithclosed frac-tures(4.2%). Theproportionsofpatientswithpolymicrobial infectionsandinfectionsduetoGNBwerealsosignificantly higheramongpatientswithopenfractures(Table1).

Themicrobiologicalfindingsindicatedthatatotalof529 infection-associatedbacterialisolateswererecovered, includ-ing 357isolatesfrom patientswithopen fractures and 172 isolatesfrompatientswithclosedfractures.Inbothgroups, the predominant isolates were Gram-positive cocci, which accountedfor53%oftheobservedinfections.GNBaccounted for45%oftheisolates;bothpatientgroupsexhibitedasimilar incidenceofGNB,althoughagreaterabsolutenumberof iso-lateswererecoveredfrompatientswithopenfracturesthan frompatientswithclosedfractures.

Staphylococcusaureusandcoagulase-negativeStaphylococcus (CoNS) specieswere the primaryinfectious agentsisolated frombothgroups.TheoverallincidenceofMRSA (methicillin-resistantS.aureus)was72%;thisincidencewas75%among patientswithopenfractures and66% amongpatients with closedfractures.Forthegroupofpatientswithopenfractures, inadditiontoCoNSspecies,Enterococcusspp.werethesecond mostagentthatwasisolated;76%oftheEnterococcusisolates exhibitedsusceptibilitytovancomycin.

A.baumanniiwasthepredominantGNBisolaterecovered frompatientswithopenfractures.P.aeruginosawasthemost frequentisolaterecoveredfrompatientswithclosedfractures. Both A. baumanniiand P. aeruginosa exhibited low rates of susceptibilitytocarbapenems(susceptibilities toimipenem of57%and47%,respectively).Anaerobic bacteriaandfungi

Table2–Comparisonofthemainmicrobiological findingsinthegroupsofpatientswithclosedandopen fractures.

Closedfractures Openfractures

Totalnumberofisolates

357 172

Primaryagents

S.aureus(56isolates–33%) 66%MRSA

S.aureus(83isolates–23%) 75%MRSA

CoNSspecies(24isolates– 14%)

CoNSspecies(51isolates–14%)

Enterococcusspp.(51isolates–14%) 76%sensitivitytovancomycin

P.aeruginosa(18isolates– 10%)

47%sensitivityto carbapenems

A.baumannii(44isolates–12%) 57%sensitivitytoimipenem

accounted for2% of the isolates. Table 2 summarizes the microbiologicalfindingsdescribedinthisstudy.

Discussion

The incidence of SSI was significantly higher in patients withopenfractures.Althoughthisfindingistobeexpected duetothe highdegreeofcontaminationobservedinthese high-energyinjuries,2_few_studies_have_proven_the_higher inci-denceofSSIinthispopulation,and noneofthem featured asampleaslargeasthatofthepresentstudy.Therewasa predominanceofGNBinfectionsandpolymicrobialinfections inthegroupofpatientswithopenfractures.Otherstudies, conducted mainlyinsoldiers stationedin theMiddle East, corroboratethesefindings.1,5–7

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rev bras ortop.2016;51(4):396–399

399 Conclusion

TheincidenceofSSIsrelatedtotheinternalfixationof frac-tures was significantly higher among patients with open fractures,indicatingthatanopenfracturecanbearisk fac-torforinfection.Thecurrentstudyalsoindicatedthatthere were a significantly elevated number of polymicrobialand GNBinfectionsamongpatientswithprioropenfractures. Fur-therstudiesare neededtoevaluatepotentialvariablesthat couldberelevanttothesefindings.

Amongthebacterialisolates,S.aureus(withahigh preva-lence of MRSA) and CoNS species were most prevalent. Enterococcusspp.(withalowrateofsensitivitytovancomycin) and A. baumannii were also prevalent among the isolates recoveredfrompatientswithopen fractures.Inaddition, P. aeruginosawasoneofthemoresignificantisolatesrecovered frompatientswithclosedfractures.TheA.baumanniiandP. aeruginosaisolatesunderscoredthelowrateofsusceptibility tocarbapenemsthatwasobservedinthepresentstudy.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

Acknowledgments

WethankAmericanJornalExpertsforeditorialandwriting assistance.

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