Andersons pediatric cardiology 1490

common)
S.hominis
S.lugdunensis
S.capitis
OralStreptococcal
MostcommoncauseinCHD.
species(Viridans
Oftensensitivetopenicillinandthird-generationcephalosporin,butresistanceto
group)
bothagentshasbeenobserved.
Streptococcus
oralis/mitis
Streptococcus
sanguinis/mutans
group
Enterococci
Morecommoninadults.
E.faecalis
Difficulttotreatduetorelativetolerancetoβ-lactamantimicrobialsandincreasing
E.faecium
resistanceinE.faecium.
Nutritionally
Difficulttoisolateandculture.Concernsoverrelativeresistancetoβ-lactams.
variantorganism
Highrelapserate,needtotreatasforenterococcalIE.
Abiotrophiaspp.
Granulicatellaspp.
Other
InfrequentbutveryaggressivecauseifIEwithseveretissuedestructionrequiring
streptococcal
surgicalintervention.

species
Streptococcus
pneumoniae
Streptococcus
pyogenes
Streptococcusmilleri
group
HACEK
Affectsbothprostheticvalvesandnativevalves.Generallybetterprognosisthan
Haemophilusspp.
somecausesofIE.
Aggregatibacterspp.
Somestrainsareβ-lactamasepositive.
Cardiobacteriumspp.
Hardtogrowinlaboratory,oftenrequireprolongedculture.Goodpick-upon
Eikenellacorodens
resectedmaterialbymolecularmethods.
Kingellaspp.
Gramnegative
Morelikelyinimmune-compromisedandneonates.
Enterobacteriaceae
Antimicrobialresistanceanissue.
(Coliforms)
Specialistadviceoncombinationtherapyandlength.
Pseudomonasspp.
Fungal
Candidaspp.CauseofbothNVEandPVE;verydifficulttotreat,requiringsurgical
resectioninmostcases,apartfrommuralIEinneonates.
Filamentousfungi.Verydifficulttomanage,almostalwaysrequiressurgical
debridementandaggressiveantifungaltherapy.

Othercauses
Oftenpartofnoncultivableorculture-negativeendocarditis.Serologictesting
Bartonellasp.
availableforsome.
Coxiellaburnetii
Goodrateofpick-uponmoleculartestingofresectedmaterial.
Tropherymawhipplei
Combinewithepidemiologicexposureforoptimaldiagnosis
Mycoplasmaspp.
Brucellaspp.
Emerging
M.chimaerarecentlyidentifiedasacauseofIEduetocontaminatedheatercoolerunits
pathogens
andbypasscircuitsusedincardiacsurgery.
Mycobacterium
chimaera

CHD,Congenitalheartdisease;IE,infectiveendocarditis;NVE,nativevalveendocarditis;PVE,
prostheticvalveendocarditis.


Table56.5
SummaryofPediatric-SpecificCohortStudiesEvaluatingChanges
inIncidence,RiskFactorsandCausativeAgentsofIE

Study

Dayet
al93

Time
Period,
StudyType

NumberofIEEpisodes

2000and
N=1588(causative
2003,US
organismsin662cases)
retrospective
cohort

Guptaet 2000–2010,
al94
USCHD
Retrospective
cohort

Sakai
2001–2012,
Bizmark interrupted
etal95
timeseries
retrospective
cohort

N=3840
estimated

N=3748(weighted
accordingtowhetherIE
appearsinanyprimary,
secondary,ortertiary
dischargecode)

%of
Patients
With
Findings/Comments
Preexisting
Cardiac
Disease/None
42%/58%
IEepisodeswithcodedorganisms,n=
622
■Staphylococcusaureus,362(57%)
■ViridansStreptococcus,124(20%)
■Coagulase-negativeStaphylococcus,91
(14%)
■MortalityhighestintetralogyofFallot
withPAandTOF
■Innon-CHDcases,highestmortalityin
infants,especiallyprematureonesand
withS.aureusinfections
53.5%/46.5% ■30.2%noorganism(culturenegative)
■S.aureus,36.6%(ofthose,46.9%hadno
underlyingcardiacdefect,28.1%withno
defect)
■OtherStaphylococcusspp.,6.5%equally

distributedbetweenthosewithand
withoutpreexistingcardiacdefect
■ViridansStreptococcus,26%(32.7%in
childrenwithunderlyingcardiacdefects,
17.9%inthosewithout)
■Trendoverstudyperiodforincreasein
streptococcalIE
■HighestmortalityinS.aureusIE
50.2%/49.8% ■StaphylococcusIE,33.6%
■Streptococcus,27.4%(VGS20.4)
■Culturenegative,30.4%
■Mainfindingwasthatincidencehasnot
changedbutdecreaseinstaphylococcal
andincreaseinstreptococcalIEinthe10to17-year-oldagegrouppost–2007
guideline

CHD,Congenitalheartdisease;IE,infectiveendocarditis;PA,pulmonaryatresia;TOF,tetralogy
ofFallot;VGS,viridansgroupstreptococci.

LaboratoryDiagnosticProcedures
BCremainsthegoldstandardinvestigationforpatientswithsuspectedIE;
however,optimalsamplingtechniques,volumes(basedonageofchild),and


cultureconditionsareessentialforanaccuratediagnosis.Inchildrenthe
followingvolumesandfrequencyarerecommended:
Volumes:
1.Infantsandyoungchildren:1to3mLperbottle
2.Olderchildren:5to7mLperbottle(upto30mLblood/day).
Frequency:

1.Threesetsofseparatevenipuncturesover24hours,ideallywithoneset
12hoursapart,butwithatleastthefirstandlastset1hourapart
2.Ifthepatientisunstableandpresentationisacute,taketwoBCsat
separatesitesimmediatelyandathirdatleast1hourlaterand
commenceempirictherapyassoonasfeasible.

NewLaboratoryDiagnosticTechniques
Techniquessuchasbroad-rangebacterial(16SrDNA)andfungal(18srDNA)
polymerasechainreactions(PCRs),pathogen-specificreal-timePCRs,and
proteomics(matrix-assistedlaserdesorption/ionizationtime-of-flightanalysis
[MALDI-TOF])havebecomewidelyavailableandshouldbeusedin
conjunctionwithstandardculturetechniques.Gene-specificprimersand
amplificationaremoresensitiveanddonotalwaysrequireasequencestepand
soaremorerapid.
1.MolecularmethodologiescandetectbacterialDNAdirectlyinblood,
and,althoughtheyhaveadvancedinrecentyears,
■Theyarestillsomewhatinsensitive,96thelikelyreasondueto
thelowcirculatingloadofbacteriainIE.
■Broad-rangePCRtechniques,bacterial(16SrDNA)and
fungal(18SrDNA),aredesignedtoamplifybothconserved
andvariableregionsofribosomalDNAbutingeneralare
ratherinsensitiveandinadditionrequireasequencingstepto
identifythepathogen.
■ContaminationwithenvironmentalDNAcanbeproblematic,
particularlyforfungal18SDNA.Optimalsampling,