Infective Endocarditis Diagnosis, Antimicrobial Therapy, and ...

e416 Circulation June 14, 2005TABLE 13.Therapy for Both Native and Prosthetic Valve Endocarditis Caused by HACEK* MicroorganismsRegimenDosage and RouteDuration,wkStrength ofRecommendationCommentsCeftriaxone† sodium 2 g/24 h IV/IM in 1 dose 4 IB Cefotaxime or another third- ororAmpicillin- sulbactam‡ 12 g/24 h IV in 4 equally divided doses 4 IIaBfourth-generation cephalosporin may besubstitutedorCiprofloxacin‡§ 1000 mg/24 h PO or 800 mg/24 h IV in 2equally divided dosesPediatric dose: Ceftriaxone 100 mg/kg per 24h IV/IM once daily; ampicillin-sulbactam 300mg/kg per 24 h IV divided into 4 or 6 equallydivided doses; ciprofloxacin 20–30 mg/kg per24 h IV/PO in 2 equally divided doses4 IIbC Fluoroquinolone therapy recommended only forpatients unable to tolerate cephalosporin andampicillin therapy; levofloxacin, gatifloxacin, ormoxifloxacin may be substituted;fluoroquinolones generally not recommendedfor patients 18 y oldProsthetic valve: patients with endocarditisinvolving prosthetic cardiac valve or otherprosthetic cardiac material should be treatedfor6wk*Haemophilus parainfluenzae, H aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae.†Patients should be informed that IM injection of ceftriaxone is painful.‡Dosage recommended for patients with normal renal function.§Fluoroquinolones are highly active in vitro against HACEK microorganisms. Published data on use of fluoroquinolone therapy for endocarditis caused by HACEKare minimal.Pediatric dose should not exceed that of a normal adult.oxacillin-susceptible staphylococci, viridans group streptococci,and enterococci, and antibiotic therapy for thesepotential pathogens should be administered for at least 6weeks.The second group of patients with culture-negative endocarditishas infection caused by uncommon or rare endocarditispathogens that do not grow in routinely used bloodculture systems. 184,187 The organisms that have garnered themost attention are Bartonella species, Chlamydia species,Coxiella burnetii, Brucella species, Legionella species, Tropherymawhippleii, and non-Candida fungi. Bartonella species,Coxiella burnetii, and Brucella species have been themost commonly identified in most series of culture-negativeendocarditis caused by fastidious organisms. Bartonella maybe more common than the other 2 and has been reported as acause of IE in 3% of cases in 3 different countries. 187Bartonella quintana is the most commonly identified species,followed by B henselae. Treatment of this wide variety ofmicroorganisms has been described anecdotally, and regimensof choice are based on limited data and can be found inother publications. Treatment choices for Bartonella endocarditisare included in Table 14 because it may be the mostcommonly seen form of endocarditis among those caused byfastidious organisms. Antibiotic regimens should include atleast 2 weeks of aminoglycoside therapy. 187Noninfectious causes of valvular vegetations can produce asyndrome similar to culture-negative endocarditis. Perhapsthe one that has received the most attention is antiphospholipidsyndrome. 188 This syndrome has been described as botha primary and a secondary syndrome and is associated withthe presence of antiphospholipid antibodies. In its secondaryform, antiphospholipid syndrome has been linked to autoimmunedisorders, particularly systemic lupus erythematosus,and malignancies. Sterile valvular vegetations form andembolize, clinically mimicking in many respects culturenegativeendocarditis. The mitral valve is most often affected,and valvular regurgitation is the predominant functionalabnormality seen.Numerous other causes of noninfective vegetative endocarditiscan mimic IE. These can be categorized into 4groups 184 : neoplasia associated (atrial myxoma, maranticendocarditis, neoplastic disease, and carcinoid); autoimmuneassociated (rheumatic carditis, systemic lupus erythematosus,polyarteritis nodosa, and Behçet’s disease); postvalvular surgery(thrombus, stitch, or other postsurgery changes); andmiscellaneous (eosinophilic heart disease, ruptured mitralchordae, and myxomatous degeneration).FungiFungal endocarditis is a relatively new syndrome and is oftena complication of medical and surgical advances. 189,190 Patientswho develop this illness usually have multiple predisposingconditions that often include the use of cardiovasculardevices, in particular, prosthetic cardiac valves and centralvenous catheters. Despite aggressive combined medical andsurgical interventions, mortality rates for fungal endocarditisare unacceptably high. The survival rate for patients withmold-related endocarditis is 20%.Candida and Aspergillus species account for the largemajority of fungal endocardial infections, and Candidarelatedendocarditis is much more common than Aspergillusrelateddisease. 189,190 Blood cultures are usually positive incases caused by the former pathogen, whereas they are rarelypositive in cases caused by the latter fungus. Thus, Aspergillusis a cause of culture-negative endocarditis, and when thisoccurs, it is usually in a patient with recent placement of aprosthetic cardiac valve. 189Historically, 2 treatment doctrines have prevailed in fungalendocarditis despite the lack of prospective trials conductedto define the most appropriate therapy. One doctrine is thatDownloaded from circ.ahajournals.org by on June 26, 2007