ConfirmedMycoplasma pneumoniaeEndocarditis

Confi rmed Mycoplasma pneumoniae EndocarditisTo the Editor: In Rosario, Argentina, during June 2005, a 15-yearold boy was hospitalized because of a 2-month history of fever.The patient had no history of cardiac disease or intravenous drug use.The results of the physical examination and the laboratory tests were within normal limits, except for an increased leukocyte count (14,000/μL) with 68% neutrophils.Transesophagic echocardiography showed mural vegetation on the right ventricle (30 mm × 20 mm) with no valve involvement.The patient was empirically treated with penicillin, gentamicin, and ceftriaxone.After treatment failed to produce a response, blood was submitted for culture for mycobacteria, brucellae, bartonellae, molds, and yeasts.BacT/ALERT bottles (bioMérieux, Durham, NC, USA), Hemoline performance biphasic medium (bioMérieux, Marcy L'Etoile, France), lysis centrifugation, and homemade culture broth were used.All culture results were negative.Results of PCR performed on serum for Actinobacillus actinomycetemcomitans were also negative.Because only the fi rst samples were obtained before antimicrobial drug administration, a false-negative result was suspected.The patient underwent surgery for pulmonary microembolisms, and the vegetation was removed 4 weeks after drug treatment had started.The histologic appearance of the vegetation was consistent with infectious endocarditis, but the culture result was negative.After 6 weeks of treatment, the patient was discharged from the hospital; however, 10 days after discharge he again became febrile and was readmitted to the hospital.The vegetation was again found.On this second admission, all cultures were performed before administration of antimicrobial